SUDEEP JOSHI | Stevens Institute of Technology (original) (raw)

Papers by SUDEEP JOSHI

Research paper thumbnail of A 3D‐Printed Hybrid Nasal Cartilage with Functional Electronic Olfaction

Research paper thumbnail of Evaluation of Transverse Piezoelectric Coefficient of ZnO Thin Films Deposited on Different Flexible Substrates: A Comparative Study on the Vibration Sensing Performance

ACS Applied Materials & Interfaces, 2014

We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelec... more We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelectric ZnO thin films deposited on four different flexible substrates for vibration sensing application. The flexible substrates employed for present experimental study were namely a metal alloy (Phynox), metal (aluminum), polyimide (Kapton), and polyester (Mylar). ZnO thin films were deposited by an RF reactive magnetron sputtering technique. ZnO thin films of similar thicknesses of 700 ± 30 nm were deposited on four different flexible substrates to have proper comparative studies. The crystallinity, surface morphology, chemical composition, and roughness of ZnO thin films were evaluated by respective material characterization techniques. The transverse piezoelectric coefficient (d 31) value for assessing the piezoelectric property of ZnO thin films on different flexible substrates was measured by a four-point bending method. ZnO thin films deposited on Phynox alloy substrate showed relatively better material characterization results and a higher piezoelectric d 31 coefficient value as compared to ZnO films on metal and polymer substrates. In order to experimentally verify the above observations, vibration sensing studies were performed. As expected, the ZnO thin film deposited on Phynox alloy substrate showed better vibration sensing performance. It has generated the highest peak to peak output voltage amplitude of 256 mV as compared to that of aluminum (224 mV), Kapton (144 mV), and Mylar (46 mV). Therefore, metal alloy flexible substrate proves to be a more suitable, advantageous, and versatile choice for integrating ZnO thin films as compared to metal and polymer flexible substrates for vibration sensing applications. The present experimental study is extremely important and helpful for the selection of a suitable flexible substrate for various applications in the field of sensor and actuator technology.

Research paper thumbnail of Flexible phynox alloy with integrated piezoelectric thin film for micro actuation application

2012 IEEE Sensors, 2012

In this paper, we report on the application aspect of piezoelectric ZnO thin film deposited on fl... more In this paper, we report on the application aspect of piezoelectric ZnO thin film deposited on flexible phynox alloy substrate. Highly crystalline piezoelectric ZnO thin films were deposited by RF reactive magnetron sputtering and were characterized by XRD, SEM, AFM analysis. Also, the effective d 33 coefficient value measurement was performed. The actuator element is a circular diaphragm of phynox alloy on to which piezoelectric ZnO thin film was deposited. ZnO film deposited actuator element was firmly fixed inside a suitable concave perspex mounting designed specifically for micro actuation purpose. The actuator element was excited at different frequencies for the supply voltages of 2V, 5V and 8V. Maximum deflection of the ZnO film deposited diaphragm was measured to be 1.25 µm at 100 Hz for the supply voltage of 8V. The developed micro actuator has the potential to be used as a micro pump for pumping nano liters to micro liters of fluids per minute for numerous biomedical and aerospace applications.

Research paper thumbnail of Distributed piezoelectric Thin Film Sensor Array for monitoring impact events

2013 IEEE SENSORS, 2013

Accurate monitoring of impact events is of paramount importance for structural health monitoring,... more Accurate monitoring of impact events is of paramount importance for structural health monitoring, quality control and failure analysis of numerous structures. The present paper reports on the application aspect of distributed piezoelectric Thin Film Sensor Array (TFSA) for the impact force measurement. The distributed TFSA consists of 3x3 sensing element matrix of piezoelectric ZnO thin film. Highly c-axis oriented piezoelectric ZnO thin film was deposited on the flexible Phynox alloy substrate by RF reactive magnetron sputtering and was characterized by FESEM and AFM techniques. The individual sensing element is a MIM (Metal Insulator Metal) type structure. The ZnO thin film acts as an impact sensing layer and is sandwiched between Phynox common electrode and silver thin film as a top electrode. The overall dimension of the developed TFSA was 3cm x 3cm, and it monitors the location, force-time history and magnitude of the impact force. The developed piezoelectric TFSA has potential applications in monitoring the impact events on several composite structures like wings of an aircraft, crash testing of vehicles and wearable sports impact indicators.

Research paper thumbnail of A novel piezoelectric ZnO nanogenerator on flexible metal alloy substrate

2012 IEEE Sensors, 2012

In this paper, we report a novel piezoelectric ZnO nanogenerator on flexible metal alloy substrat... more In this paper, we report a novel piezoelectric ZnO nanogenerator on flexible metal alloy substrate (Phynox alloy) for energy harvesting and sensing applications. The vertically aligned ZnO nanowires are sandwiched between Au electrodes. The aligned growth of ZnO nanowires have been successfully synthesized on Au coated metal alloy substrate by hydrothermal method at low temperature (95±1 °C). The as-synthesized vertically aligned ZnO nanowires were characterized using FE-SEM. Further, PMMA is spin coated over the aligned ZnO nanowires for the purpose of their long term stability. The fabricated nanogenerator is of size 30mm x 6mm. From energy harvesting point of view, the response of the nanogenerator due to finger tip impacts ranges from 0.9 V to 1.4V. Also for sensing application, the maximum output voltage response of the nanogenerator is found to be 2.86V due to stainless steel (SS) ball impact and 0.92 V due to plastic ball impact.

Research paper thumbnail of AFM cantilever with integrated piezoelectric thin film for micro-actuation

2012 IEEE Sensors, 2012

This work presents micro-actuation of atomic force microscopy (AFM) cantilevers using piezoelectr... more This work presents micro-actuation of atomic force microscopy (AFM) cantilevers using piezoelectric Zinc Oxide (ZnO) thin film. In tapping mode AFM, the cantilever is driven near its resonant frequency by an external oscillator such as piezotube or stack of piezoelectric material. Use of integrated piezoelectric thin film for AFM cantilever eliminates the problems like inaccurate tuning and unwanted vibration modes. In this work, silicon AFM cantilevers were sputter deposited with ZnO piezoelectric film along with top and bottom metallic electrodes. The self-excitation of the ZnO coated AFM cantilever was studied using Laser Doppler Vibrometer (LDV). At its resonant frequency (227.11 kHz), the cantilever displacement varies linearly with applied excitation voltage. We observed an increase in the actuation response (131nm/V) due to improved quality of ZnO films deposited at 200 °C. I.

Research paper thumbnail of A novel gas flow sensing application using piezoelectric ZnO thin films deposited on Phynox alloy

Sensors and Actuators A: Physical, 2012

ABSTRACT We report on the novel flow sensing application of piezoelectric ZnO thin film deposited... more ABSTRACT We report on the novel flow sensing application of piezoelectric ZnO thin film deposited on Phynox alloy sensing element. Characterization of piezoelectric ZnO films deposited on Phynox (Elgiloy) substrate at different RF powers is discussed. ZnO films deposited at RF power of 100 W were found to have fine c-axis orientation, possesses excellent surface morphology with lower rms surface roughness of 1.87 nm and maximum d31 coefficient value 4.7 pm V−1. The thin cantilever strip of Phynox alloy with ZnO film as a sensing layer for flow sensing has been tested for flow rates ranging from 2 to 18 L min−1. A detailed theoretical analysis of the experimental set-up showing the relationship between output voltage and force at a particular flow rate has been discussed. The sensitivity of flow sensing element is ∼18 mV/(L min−1) and typical response time is of the order of 20 m s. The sensing element is calibrated using in-house developed testing set-up.

Research paper thumbnail of A novel piezoelectric thin film impact sensor: Application in non-destructive material discrimination

Sensors and Actuators A: Physical, 2013

We report on the design, development, and performance study of a packaged piezoelectric thin film... more We report on the design, development, and performance study of a packaged piezoelectric thin film impact sensor, and its potential application in non-destructive material discrimination. The impact sensing element employed was a thin circular diaphragm of flexible Phynox alloy. Piezoelectric ZnO thin film as an impact sensing layer was deposited on to the Phynox alloy diaphragm by RF reactive magnetron sputtering. Deposited ZnO thin film was characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) techniques. The d 31 piezoelectric coefficient value of ZnO thin film was 4.7 pm V −1 , as measured by 4-point bending method. ZnO film deposited diaphragm based sensing element was properly packaged in a suitable housing made of High Density Polyethylene (HDPE) material. Packaged impact sensor was used in an experimental setup , which was designed and developed in-house for non-destructive material discrimination studies. Materials of different densities (iron, glass, wood, and plastic) were used as test specimens for material discrimination studies. The analysis of output voltage waveforms obtained reveals lots of valuable information about the impacted material. Impact sensor was able to discriminate the test materials on the basis of the difference in their densities. The output response of packaged impact sensor shows high linearity and repeatability. The packaged impact sensor discussed in this paper is highly sensitive, reliable, and cost-effective.

Research paper thumbnail of Effect of post-deposition annealing on transverse piezoelectric coefficient and vibration sensing performance of ZnO thin films

Applied Surface Science, 2014

The present experimental study investigates the influence of post-deposition annealing on the tra... more The present experimental study investigates the influence of post-deposition annealing on the transverse piezoelectric coefficient (d 31) value of ZnO thin films deposited on a flexible metal alloy substrate, and its relationship with the vibration sensing performance. Highly c-axis oriented and crystalline ZnO thin films were deposited on flexible Phynox alloy substrate via radio frequency (RF) reactive magnetron sputtering. ZnO thin film samples were annealed at different temperatures ranging from 100 • C to 500 • C, resulting in the temperature of 300 • C determined as the optimum annealing temperature. The crystallinity, morphology, microstructure, and rms surface roughness of annealed ZnO thin films were systematically investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM), respectively. The piezoelectric d 31 coefficient value was measured by 4-point bending method. ZnO thin film annealed at 300 • C was highly c-axis oriented, crystalline, possesses fine surface morphology with uniformity in the grain size. This film showed higher d 31 coefficient value of 7.2 pm V −1. A suitable in-house designed and developed experimental setup , for evaluating the vibration sensing performance of annealed ZnO thin films is discussed. As expected the ZnO thin film annealed at 300 • C showed relatively better result for vibration sensing studies. It generates comparatively higher peak output voltage of 147 mV, due to improved structural and morphological properties, and higher piezoelectric d 31 coefficient value.

Research paper thumbnail of SOLID: Soft-lithography on SLA 3D printed moulds for fast, versatile, and accessible high-resolution fabrication of customised multiscale cell culture devices with complex designs

Cell culture devices, such as microwells and microfluidic chips, are designed to increase the com... more Cell culture devices, such as microwells and microfluidic chips, are designed to increase the complexity of cell-based models whilst retaining control over culture conditions and have become indispensable platforms for biological systems modelling. From microtopography, microwells, plating devices and microfluidic systems to larger constructs for specific applications like live imaging chamber slides, a wide variety of culture devices with different geometries have become indispensable in biology labs. However, due to the techniques used for their manufacture, such as photolithography, the fabrication of such devices is costly and requires specialised experience, facilities, and time. Whilst commercially available systems are available, these are also costly, and lack the potential for customisation. This renders customised cell culture devices out of reach for most wet labs.Taking advantage of low-cost, high-resolution desktop resin 3D printers combined with PDMS soft lithography w...

Research paper thumbnail of Towards Flexible Sensors and Actuators : Application Aspect of Piezoelectronic Thin Film

Research paper thumbnail of Tailoring Thin-Film Piezoelectrics for Crash Sensing

Small (Weinheim an der Bergstrasse, Germany), Jan 25, 2018

Crash sensing and its assessment play a pivotal role in autonomous vehicles for preventing fatal ... more Crash sensing and its assessment play a pivotal role in autonomous vehicles for preventing fatal casualties. Existing crash sensors are severely bottlenecked by sluggish response time, rigid mechanical components, and space constraints. Miniaturized sensors embedded with custom-tailored nanomaterials upholds potential to overcome these limitations. In this article, piezoelectric Zinc-Oxide thin film as a crash sensing layer is integrated onto a flexible metal-alloy cantilever. Material characterization studies are conducted to confirm piezoelectric property of sputtered ZnO film. The piezoelectric d coefficient value of ZnO film was 7.2 pm V . The ZnO sensing element is firmly mounted on a scaled car model and used in a crash sensing experimental set-up. A comprehensive theoretical analysis for two different real scenarios (nearly elastic and nearly inelastic collision) of crash events followed by experimental study is discussed. The crash sensor's output exhibits a linear relat...

Research paper thumbnail of Bacterial Nanobionics via 3D Printing

Nano letters, Jan 7, 2018

Investigating the multidimensional integration between different microbiological kingdoms possess... more Investigating the multidimensional integration between different microbiological kingdoms possesses potential toward engineering next-generation bionic architectures. Bacterial and fungal kingdom exhibits mutual symbiosis that can offer advanced functionalities to these bionic architectures. Moreover, functional nanomaterials can serve as probing agents for accessing newer information from microbial organisms due to their dimensional similarities. In this article, a bionic mushroom was created by intertwining cyanobacterial cells with graphene nanoribbons (GNRs) onto the umbrella-shaped pileus of mushroom for photosynthetic bioelectricity generation. These seamlessly merged GNRs function as agents for mediating extracellular electron transport from cyanobacteria resulting in photocurrent generation. Additionally, three-dimensional (3D) printing technique was used to assemble cyanobacterial cells in anisotropic, densely packed geometry resulting in adequate cell-population density fo...

Research paper thumbnail of Evaluation of Transverse Piezoelectric Coefficient of ZnO Thin Films Deposited on Different Flexible Substrates: A Comparative Study on the Vibration Sensing Performance

We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelec... more We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelectric ZnO thin films deposited on four different flexible substrates for vibration sensing application. The flexible substrates employed for present experimental study were namely a metal alloy (Phynox), metal (aluminum), polyimide (Kapton), and polyester (Mylar). ZnO thin films were deposited by an RF reactive magnetron sputtering technique. ZnO thin films of similar thicknesses of 700 ± 30 nm were deposited on four different flexible substrates to have proper comparative studies. The crystallinity, surface morphology, chemical composition, and roughness of ZnO thin films were evaluated by respective material characterization techniques. The transverse piezoelectric coefficient (d 31) value for assessing the piezoelectric property of ZnO thin films on different flexible substrates was measured by a four-point bending method. ZnO thin films deposited on Phynox alloy substrate showed relat...

Research paper thumbnail of A 3D-Printed Hybrid Nasal Cartilage with Functional Electronic Olfaction

Advanced Science, 2019

Advances in biomanufacturing techniques have opened the doors to recapitulate human sensory organ... more Advances in biomanufacturing techniques have opened the doors to
recapitulate human sensory organs such as the nose and ear in vitro
with adequate levels of functionality. Such advancements have enabled
simultaneous targeting of two challenges in engineered sensory organs,
especially the nose: i) mechanically robust reconstruction of the nasal
cartilage with high precision and ii) replication of the nose functionality:
odor perception. Hybrid nasal organs can be equipped with remarkable
capabilities such as augmented olfactory perception. Herein, a proof-ofconcept for an odor-perceptive nose-like hybrid, which is composed of a mechanically robust cartilage-like construct and a biocompatible biosensing platform, is proposed. Specifcally, 3D cartilage-like tissue constructs are created by multi-material 3D bioprinting using mechanically tunable chondrocyte-laden bioinks. In addition, by optimizing the composition of stiff and soft bioinks in macro-scale printed constructs, the competence of this system in providing improved viability and recapitulation of chondrocyte cell behavior in mechanically robust 3D constructs is demonstrated. Furthermore, the engineered cartilage-like tissue construct is integrated with an electrochemical biosensing system to bring functional olfactory sensations toward multiple specifc airway disease biomarkers, explosives, and toxins
under biocompatible conditions. Proposed hybrid constructs can lay the
groundwork for functional bionic interfaces and humanoid cyborgs.

Research paper thumbnail of Study on the suitability of piezoelectric thin film for impact sensing application

Research paper thumbnail of Towards Flexible Sensors and Actuators: Application Aspect of Piezoelectric Thin Films

Research paper thumbnail of Flexible Phynox Alloy with Integrated Piezoelectric Thin Film for Micro Actuation Application

— In this paper, we report on the application aspect of piezoelectric ZnO thin film deposited on ... more — In this paper, we report on the application aspect of piezoelectric ZnO thin film deposited on flexible phynox alloy substrate. Highly crystalline piezoelectric ZnO thin films were deposited by RF reactive magnetron sputtering and were characterized by XRD, SEM, AFM analysis. Also, the effective d 33 coefficient value measurement was performed. The actuator element is a circular diaphragm of phynox alloy on to which piezoelectric ZnO thin film was deposited. ZnO film deposited actuator element was firmly fixed inside a suitable concave perspex mounting designed specifically for micro actuation purpose. The actuator element was excited at different frequencies for the supply voltages of 2V, 5V and 8V. Maximum deflection of the ZnO film deposited diaphragm was measured to be 1.25 µm at 100 Hz for the supply voltage of 8V. The developed micro actuator has the potential to be used as a micro pump for pumping nano liters to micro liters of fluids per minute for numerous biomedical and aerospace applications.

Research paper thumbnail of A novel piezoelectric thin film impact sensor: Application in non-destructive material discrimination

We report on the design, development, and performance study of a packaged piezoelectric thin film... more We report on the design, development, and performance study of a packaged piezoelectric thin film impact sensor, and its potential application in non-destructive material discrimination. The impact sensing element employed was a thin circular diaphragm of flexible Phynox alloy. Piezoelectric ZnO thin film as an impact sensing layer was deposited on to the Phynox alloy diaphragm by RF reactive mag-netron sputtering. Deposited ZnO thin film was characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) techniques. The d 31 piezoelectric coefficient value of ZnO thin film was 4.7 pm V −1 , as measured by 4-point bending method. ZnO film deposited diaphragm based sensing element was properly packaged in a suitable housing made of High Density Polyethylene (HDPE) material. Packaged impact sensor was used in an experimental setup , which was designed and developed in-house for non-destructive material discrimination studies. Materials of different densities (iron, glass, wood, and plastic) were used as test specimens for material discrimination studies. The analysis of output voltage waveforms obtained reveals lots of valuable information about the impacted material. Impact sensor was able to discriminate the test materials on the basis of the difference in their densities. The output response of packaged impact sensor shows high linearity and repeatability. The packaged impact sensor discussed in this paper is highly sensitive, reliable, and cost-effective.

Research paper thumbnail of Effect of post-deposition annealing on transverse piezoelectric coefficient and vibration sensing performance of ZnO thin films

The present experimental study investigates the influence of post-deposition annealing on the tra... more The present experimental study investigates the influence of post-deposition annealing on the transverse piezoelectric coefficient (d 31) value of ZnO thin films deposited on a flexible metal alloy substrate, and its relationship with the vibration sensing performance. Highly c-axis oriented and crystalline ZnO thin films were deposited on flexible Phynox alloy substrate via radio frequency (RF) reactive mag-netron sputtering. ZnO thin film samples were annealed at different temperatures ranging from 100 • C to 500 • C, resulting in the temperature of 300 • C determined as the optimum annealing temperature. The crystallinity, morphology, microstructure, and rms surface roughness of annealed ZnO thin films were systematically investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM), respectively. The piezoelectric d 31 coefficient value was measured by 4-point bending method. ZnO thin film annealed at 300 • C was highly c-axis oriented, crystalline, possesses fine surface morphology with uniformity in the grain size. This film showed higher d 31 coefficient value of 7.2 pm V −1. A suitable in-house designed and developed experimental setup , for evaluating the vibration sensing performance of annealed ZnO thin films is discussed. As expected the ZnO thin film annealed at 300 • C showed relatively better result for vibration sensing studies. It generates comparatively higher peak output voltage of 147 mV, due to improved structural and morphological properties, and higher piezoelectric d 31 coefficient value.

Research paper thumbnail of A 3D‐Printed Hybrid Nasal Cartilage with Functional Electronic Olfaction

Research paper thumbnail of Evaluation of Transverse Piezoelectric Coefficient of ZnO Thin Films Deposited on Different Flexible Substrates: A Comparative Study on the Vibration Sensing Performance

ACS Applied Materials & Interfaces, 2014

We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelec... more We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelectric ZnO thin films deposited on four different flexible substrates for vibration sensing application. The flexible substrates employed for present experimental study were namely a metal alloy (Phynox), metal (aluminum), polyimide (Kapton), and polyester (Mylar). ZnO thin films were deposited by an RF reactive magnetron sputtering technique. ZnO thin films of similar thicknesses of 700 ± 30 nm were deposited on four different flexible substrates to have proper comparative studies. The crystallinity, surface morphology, chemical composition, and roughness of ZnO thin films were evaluated by respective material characterization techniques. The transverse piezoelectric coefficient (d 31) value for assessing the piezoelectric property of ZnO thin films on different flexible substrates was measured by a four-point bending method. ZnO thin films deposited on Phynox alloy substrate showed relatively better material characterization results and a higher piezoelectric d 31 coefficient value as compared to ZnO films on metal and polymer substrates. In order to experimentally verify the above observations, vibration sensing studies were performed. As expected, the ZnO thin film deposited on Phynox alloy substrate showed better vibration sensing performance. It has generated the highest peak to peak output voltage amplitude of 256 mV as compared to that of aluminum (224 mV), Kapton (144 mV), and Mylar (46 mV). Therefore, metal alloy flexible substrate proves to be a more suitable, advantageous, and versatile choice for integrating ZnO thin films as compared to metal and polymer flexible substrates for vibration sensing applications. The present experimental study is extremely important and helpful for the selection of a suitable flexible substrate for various applications in the field of sensor and actuator technology.

Research paper thumbnail of Flexible phynox alloy with integrated piezoelectric thin film for micro actuation application

2012 IEEE Sensors, 2012

In this paper, we report on the application aspect of piezoelectric ZnO thin film deposited on fl... more In this paper, we report on the application aspect of piezoelectric ZnO thin film deposited on flexible phynox alloy substrate. Highly crystalline piezoelectric ZnO thin films were deposited by RF reactive magnetron sputtering and were characterized by XRD, SEM, AFM analysis. Also, the effective d 33 coefficient value measurement was performed. The actuator element is a circular diaphragm of phynox alloy on to which piezoelectric ZnO thin film was deposited. ZnO film deposited actuator element was firmly fixed inside a suitable concave perspex mounting designed specifically for micro actuation purpose. The actuator element was excited at different frequencies for the supply voltages of 2V, 5V and 8V. Maximum deflection of the ZnO film deposited diaphragm was measured to be 1.25 µm at 100 Hz for the supply voltage of 8V. The developed micro actuator has the potential to be used as a micro pump for pumping nano liters to micro liters of fluids per minute for numerous biomedical and aerospace applications.

Research paper thumbnail of Distributed piezoelectric Thin Film Sensor Array for monitoring impact events

2013 IEEE SENSORS, 2013

Accurate monitoring of impact events is of paramount importance for structural health monitoring,... more Accurate monitoring of impact events is of paramount importance for structural health monitoring, quality control and failure analysis of numerous structures. The present paper reports on the application aspect of distributed piezoelectric Thin Film Sensor Array (TFSA) for the impact force measurement. The distributed TFSA consists of 3x3 sensing element matrix of piezoelectric ZnO thin film. Highly c-axis oriented piezoelectric ZnO thin film was deposited on the flexible Phynox alloy substrate by RF reactive magnetron sputtering and was characterized by FESEM and AFM techniques. The individual sensing element is a MIM (Metal Insulator Metal) type structure. The ZnO thin film acts as an impact sensing layer and is sandwiched between Phynox common electrode and silver thin film as a top electrode. The overall dimension of the developed TFSA was 3cm x 3cm, and it monitors the location, force-time history and magnitude of the impact force. The developed piezoelectric TFSA has potential applications in monitoring the impact events on several composite structures like wings of an aircraft, crash testing of vehicles and wearable sports impact indicators.

Research paper thumbnail of A novel piezoelectric ZnO nanogenerator on flexible metal alloy substrate

2012 IEEE Sensors, 2012

In this paper, we report a novel piezoelectric ZnO nanogenerator on flexible metal alloy substrat... more In this paper, we report a novel piezoelectric ZnO nanogenerator on flexible metal alloy substrate (Phynox alloy) for energy harvesting and sensing applications. The vertically aligned ZnO nanowires are sandwiched between Au electrodes. The aligned growth of ZnO nanowires have been successfully synthesized on Au coated metal alloy substrate by hydrothermal method at low temperature (95±1 °C). The as-synthesized vertically aligned ZnO nanowires were characterized using FE-SEM. Further, PMMA is spin coated over the aligned ZnO nanowires for the purpose of their long term stability. The fabricated nanogenerator is of size 30mm x 6mm. From energy harvesting point of view, the response of the nanogenerator due to finger tip impacts ranges from 0.9 V to 1.4V. Also for sensing application, the maximum output voltage response of the nanogenerator is found to be 2.86V due to stainless steel (SS) ball impact and 0.92 V due to plastic ball impact.

Research paper thumbnail of AFM cantilever with integrated piezoelectric thin film for micro-actuation

2012 IEEE Sensors, 2012

This work presents micro-actuation of atomic force microscopy (AFM) cantilevers using piezoelectr... more This work presents micro-actuation of atomic force microscopy (AFM) cantilevers using piezoelectric Zinc Oxide (ZnO) thin film. In tapping mode AFM, the cantilever is driven near its resonant frequency by an external oscillator such as piezotube or stack of piezoelectric material. Use of integrated piezoelectric thin film for AFM cantilever eliminates the problems like inaccurate tuning and unwanted vibration modes. In this work, silicon AFM cantilevers were sputter deposited with ZnO piezoelectric film along with top and bottom metallic electrodes. The self-excitation of the ZnO coated AFM cantilever was studied using Laser Doppler Vibrometer (LDV). At its resonant frequency (227.11 kHz), the cantilever displacement varies linearly with applied excitation voltage. We observed an increase in the actuation response (131nm/V) due to improved quality of ZnO films deposited at 200 °C. I.

Research paper thumbnail of A novel gas flow sensing application using piezoelectric ZnO thin films deposited on Phynox alloy

Sensors and Actuators A: Physical, 2012

ABSTRACT We report on the novel flow sensing application of piezoelectric ZnO thin film deposited... more ABSTRACT We report on the novel flow sensing application of piezoelectric ZnO thin film deposited on Phynox alloy sensing element. Characterization of piezoelectric ZnO films deposited on Phynox (Elgiloy) substrate at different RF powers is discussed. ZnO films deposited at RF power of 100 W were found to have fine c-axis orientation, possesses excellent surface morphology with lower rms surface roughness of 1.87 nm and maximum d31 coefficient value 4.7 pm V−1. The thin cantilever strip of Phynox alloy with ZnO film as a sensing layer for flow sensing has been tested for flow rates ranging from 2 to 18 L min−1. A detailed theoretical analysis of the experimental set-up showing the relationship between output voltage and force at a particular flow rate has been discussed. The sensitivity of flow sensing element is ∼18 mV/(L min−1) and typical response time is of the order of 20 m s. The sensing element is calibrated using in-house developed testing set-up.

Research paper thumbnail of A novel piezoelectric thin film impact sensor: Application in non-destructive material discrimination

Sensors and Actuators A: Physical, 2013

We report on the design, development, and performance study of a packaged piezoelectric thin film... more We report on the design, development, and performance study of a packaged piezoelectric thin film impact sensor, and its potential application in non-destructive material discrimination. The impact sensing element employed was a thin circular diaphragm of flexible Phynox alloy. Piezoelectric ZnO thin film as an impact sensing layer was deposited on to the Phynox alloy diaphragm by RF reactive magnetron sputtering. Deposited ZnO thin film was characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) techniques. The d 31 piezoelectric coefficient value of ZnO thin film was 4.7 pm V −1 , as measured by 4-point bending method. ZnO film deposited diaphragm based sensing element was properly packaged in a suitable housing made of High Density Polyethylene (HDPE) material. Packaged impact sensor was used in an experimental setup , which was designed and developed in-house for non-destructive material discrimination studies. Materials of different densities (iron, glass, wood, and plastic) were used as test specimens for material discrimination studies. The analysis of output voltage waveforms obtained reveals lots of valuable information about the impacted material. Impact sensor was able to discriminate the test materials on the basis of the difference in their densities. The output response of packaged impact sensor shows high linearity and repeatability. The packaged impact sensor discussed in this paper is highly sensitive, reliable, and cost-effective.

Research paper thumbnail of Effect of post-deposition annealing on transverse piezoelectric coefficient and vibration sensing performance of ZnO thin films

Applied Surface Science, 2014

The present experimental study investigates the influence of post-deposition annealing on the tra... more The present experimental study investigates the influence of post-deposition annealing on the transverse piezoelectric coefficient (d 31) value of ZnO thin films deposited on a flexible metal alloy substrate, and its relationship with the vibration sensing performance. Highly c-axis oriented and crystalline ZnO thin films were deposited on flexible Phynox alloy substrate via radio frequency (RF) reactive magnetron sputtering. ZnO thin film samples were annealed at different temperatures ranging from 100 • C to 500 • C, resulting in the temperature of 300 • C determined as the optimum annealing temperature. The crystallinity, morphology, microstructure, and rms surface roughness of annealed ZnO thin films were systematically investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM), respectively. The piezoelectric d 31 coefficient value was measured by 4-point bending method. ZnO thin film annealed at 300 • C was highly c-axis oriented, crystalline, possesses fine surface morphology with uniformity in the grain size. This film showed higher d 31 coefficient value of 7.2 pm V −1. A suitable in-house designed and developed experimental setup , for evaluating the vibration sensing performance of annealed ZnO thin films is discussed. As expected the ZnO thin film annealed at 300 • C showed relatively better result for vibration sensing studies. It generates comparatively higher peak output voltage of 147 mV, due to improved structural and morphological properties, and higher piezoelectric d 31 coefficient value.

Research paper thumbnail of SOLID: Soft-lithography on SLA 3D printed moulds for fast, versatile, and accessible high-resolution fabrication of customised multiscale cell culture devices with complex designs

Cell culture devices, such as microwells and microfluidic chips, are designed to increase the com... more Cell culture devices, such as microwells and microfluidic chips, are designed to increase the complexity of cell-based models whilst retaining control over culture conditions and have become indispensable platforms for biological systems modelling. From microtopography, microwells, plating devices and microfluidic systems to larger constructs for specific applications like live imaging chamber slides, a wide variety of culture devices with different geometries have become indispensable in biology labs. However, due to the techniques used for their manufacture, such as photolithography, the fabrication of such devices is costly and requires specialised experience, facilities, and time. Whilst commercially available systems are available, these are also costly, and lack the potential for customisation. This renders customised cell culture devices out of reach for most wet labs.Taking advantage of low-cost, high-resolution desktop resin 3D printers combined with PDMS soft lithography w...

Research paper thumbnail of Towards Flexible Sensors and Actuators : Application Aspect of Piezoelectronic Thin Film

Research paper thumbnail of Tailoring Thin-Film Piezoelectrics for Crash Sensing

Small (Weinheim an der Bergstrasse, Germany), Jan 25, 2018

Crash sensing and its assessment play a pivotal role in autonomous vehicles for preventing fatal ... more Crash sensing and its assessment play a pivotal role in autonomous vehicles for preventing fatal casualties. Existing crash sensors are severely bottlenecked by sluggish response time, rigid mechanical components, and space constraints. Miniaturized sensors embedded with custom-tailored nanomaterials upholds potential to overcome these limitations. In this article, piezoelectric Zinc-Oxide thin film as a crash sensing layer is integrated onto a flexible metal-alloy cantilever. Material characterization studies are conducted to confirm piezoelectric property of sputtered ZnO film. The piezoelectric d coefficient value of ZnO film was 7.2 pm V . The ZnO sensing element is firmly mounted on a scaled car model and used in a crash sensing experimental set-up. A comprehensive theoretical analysis for two different real scenarios (nearly elastic and nearly inelastic collision) of crash events followed by experimental study is discussed. The crash sensor's output exhibits a linear relat...

Research paper thumbnail of Bacterial Nanobionics via 3D Printing

Nano letters, Jan 7, 2018

Investigating the multidimensional integration between different microbiological kingdoms possess... more Investigating the multidimensional integration between different microbiological kingdoms possesses potential toward engineering next-generation bionic architectures. Bacterial and fungal kingdom exhibits mutual symbiosis that can offer advanced functionalities to these bionic architectures. Moreover, functional nanomaterials can serve as probing agents for accessing newer information from microbial organisms due to their dimensional similarities. In this article, a bionic mushroom was created by intertwining cyanobacterial cells with graphene nanoribbons (GNRs) onto the umbrella-shaped pileus of mushroom for photosynthetic bioelectricity generation. These seamlessly merged GNRs function as agents for mediating extracellular electron transport from cyanobacteria resulting in photocurrent generation. Additionally, three-dimensional (3D) printing technique was used to assemble cyanobacterial cells in anisotropic, densely packed geometry resulting in adequate cell-population density fo...

Research paper thumbnail of Evaluation of Transverse Piezoelectric Coefficient of ZnO Thin Films Deposited on Different Flexible Substrates: A Comparative Study on the Vibration Sensing Performance

We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelec... more We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelectric ZnO thin films deposited on four different flexible substrates for vibration sensing application. The flexible substrates employed for present experimental study were namely a metal alloy (Phynox), metal (aluminum), polyimide (Kapton), and polyester (Mylar). ZnO thin films were deposited by an RF reactive magnetron sputtering technique. ZnO thin films of similar thicknesses of 700 ± 30 nm were deposited on four different flexible substrates to have proper comparative studies. The crystallinity, surface morphology, chemical composition, and roughness of ZnO thin films were evaluated by respective material characterization techniques. The transverse piezoelectric coefficient (d 31) value for assessing the piezoelectric property of ZnO thin films on different flexible substrates was measured by a four-point bending method. ZnO thin films deposited on Phynox alloy substrate showed relat...

Research paper thumbnail of A 3D-Printed Hybrid Nasal Cartilage with Functional Electronic Olfaction

Advanced Science, 2019

Advances in biomanufacturing techniques have opened the doors to recapitulate human sensory organ... more Advances in biomanufacturing techniques have opened the doors to
recapitulate human sensory organs such as the nose and ear in vitro
with adequate levels of functionality. Such advancements have enabled
simultaneous targeting of two challenges in engineered sensory organs,
especially the nose: i) mechanically robust reconstruction of the nasal
cartilage with high precision and ii) replication of the nose functionality:
odor perception. Hybrid nasal organs can be equipped with remarkable
capabilities such as augmented olfactory perception. Herein, a proof-ofconcept for an odor-perceptive nose-like hybrid, which is composed of a mechanically robust cartilage-like construct and a biocompatible biosensing platform, is proposed. Specifcally, 3D cartilage-like tissue constructs are created by multi-material 3D bioprinting using mechanically tunable chondrocyte-laden bioinks. In addition, by optimizing the composition of stiff and soft bioinks in macro-scale printed constructs, the competence of this system in providing improved viability and recapitulation of chondrocyte cell behavior in mechanically robust 3D constructs is demonstrated. Furthermore, the engineered cartilage-like tissue construct is integrated with an electrochemical biosensing system to bring functional olfactory sensations toward multiple specifc airway disease biomarkers, explosives, and toxins
under biocompatible conditions. Proposed hybrid constructs can lay the
groundwork for functional bionic interfaces and humanoid cyborgs.

Research paper thumbnail of Study on the suitability of piezoelectric thin film for impact sensing application

Research paper thumbnail of Towards Flexible Sensors and Actuators: Application Aspect of Piezoelectric Thin Films

Research paper thumbnail of Flexible Phynox Alloy with Integrated Piezoelectric Thin Film for Micro Actuation Application

— In this paper, we report on the application aspect of piezoelectric ZnO thin film deposited on ... more — In this paper, we report on the application aspect of piezoelectric ZnO thin film deposited on flexible phynox alloy substrate. Highly crystalline piezoelectric ZnO thin films were deposited by RF reactive magnetron sputtering and were characterized by XRD, SEM, AFM analysis. Also, the effective d 33 coefficient value measurement was performed. The actuator element is a circular diaphragm of phynox alloy on to which piezoelectric ZnO thin film was deposited. ZnO film deposited actuator element was firmly fixed inside a suitable concave perspex mounting designed specifically for micro actuation purpose. The actuator element was excited at different frequencies for the supply voltages of 2V, 5V and 8V. Maximum deflection of the ZnO film deposited diaphragm was measured to be 1.25 µm at 100 Hz for the supply voltage of 8V. The developed micro actuator has the potential to be used as a micro pump for pumping nano liters to micro liters of fluids per minute for numerous biomedical and aerospace applications.

Research paper thumbnail of A novel piezoelectric thin film impact sensor: Application in non-destructive material discrimination

We report on the design, development, and performance study of a packaged piezoelectric thin film... more We report on the design, development, and performance study of a packaged piezoelectric thin film impact sensor, and its potential application in non-destructive material discrimination. The impact sensing element employed was a thin circular diaphragm of flexible Phynox alloy. Piezoelectric ZnO thin film as an impact sensing layer was deposited on to the Phynox alloy diaphragm by RF reactive mag-netron sputtering. Deposited ZnO thin film was characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) techniques. The d 31 piezoelectric coefficient value of ZnO thin film was 4.7 pm V −1 , as measured by 4-point bending method. ZnO film deposited diaphragm based sensing element was properly packaged in a suitable housing made of High Density Polyethylene (HDPE) material. Packaged impact sensor was used in an experimental setup , which was designed and developed in-house for non-destructive material discrimination studies. Materials of different densities (iron, glass, wood, and plastic) were used as test specimens for material discrimination studies. The analysis of output voltage waveforms obtained reveals lots of valuable information about the impacted material. Impact sensor was able to discriminate the test materials on the basis of the difference in their densities. The output response of packaged impact sensor shows high linearity and repeatability. The packaged impact sensor discussed in this paper is highly sensitive, reliable, and cost-effective.

Research paper thumbnail of Effect of post-deposition annealing on transverse piezoelectric coefficient and vibration sensing performance of ZnO thin films

The present experimental study investigates the influence of post-deposition annealing on the tra... more The present experimental study investigates the influence of post-deposition annealing on the transverse piezoelectric coefficient (d 31) value of ZnO thin films deposited on a flexible metal alloy substrate, and its relationship with the vibration sensing performance. Highly c-axis oriented and crystalline ZnO thin films were deposited on flexible Phynox alloy substrate via radio frequency (RF) reactive mag-netron sputtering. ZnO thin film samples were annealed at different temperatures ranging from 100 • C to 500 • C, resulting in the temperature of 300 • C determined as the optimum annealing temperature. The crystallinity, morphology, microstructure, and rms surface roughness of annealed ZnO thin films were systematically investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM), respectively. The piezoelectric d 31 coefficient value was measured by 4-point bending method. ZnO thin film annealed at 300 • C was highly c-axis oriented, crystalline, possesses fine surface morphology with uniformity in the grain size. This film showed higher d 31 coefficient value of 7.2 pm V −1. A suitable in-house designed and developed experimental setup , for evaluating the vibration sensing performance of annealed ZnO thin films is discussed. As expected the ZnO thin film annealed at 300 • C showed relatively better result for vibration sensing studies. It generates comparatively higher peak output voltage of 147 mV, due to improved structural and morphological properties, and higher piezoelectric d 31 coefficient value.