Mingqing Wang - Academia.edu (original) (raw)

Papers by Mingqing Wang

Current Applied Physics, 2020

Inverted perovskite solar cells (p-in PSCs) have been fascinated due to rapid progress of perform... more Inverted perovskite solar cells (p-in PSCs) have been fascinated due to rapid progress of performance in recent years. PEDOT: PSS is commonly used hole transport material (HTM) in p-in PSCs which is hygroscopic and acidic in nature that leads towards poor performance of device thus hinders commercialization of PSCs. Therefore, it is necessary to replace PEDOT: PSS with stable HTM in p-in PSCs. In this paper, theoretical study is carried out to investigate various physical parameters that can affect the performance of p-in PSCs with copper iodide (CuI) as HTM and phenyl-C61-butyric acid methyl ester (PCBM) as ETM. These parameters include the effect of doping density of ETM, absorber, and HTM as well as defect density and thickness of absorber on the performance of p-in PSCs. In addition, hole mobility and thickness of HTM is also investigated. It is found that performance of p-in PSC is strongly dependent on defect density and thickness of absorber layer while other physical parameters have minor influence on the performance of device. Upon final optimization, device attains PCE of more than 21 % which is encouraging. These results show that CuI as HTM is a potential choice for p-in PSCs.

CrystEngComm, 2017

Tuning the morphology, composition and photoluminescence emission over almost the entire visible ... more Tuning the morphology, composition and photoluminescence emission over almost the entire visible region of all-inorganic cesium lead halide nanocrystals by a general and facile one-pot synthetic approach.

Semiconductor Science and Technology, 2018

Hole transport material (HTM) plays an important role in the efficiency and stability of perovski... more Hole transport material (HTM) plays an important role in the efficiency and stability of perovskite solar cells (PSCs). Spiro-MeOTAD, the commonly used HTM, is costly and can be easily degraded by heat and moisture, thus offering hindrance to commercialize PSCs. There is dire need to find an alternate inorganic and stable HTM to exploit PSCs with their maximum capability. In this paper, a comprehensive device simulation is used to study various possible parameters that can influence the performance of perovskite solar cell with CuI as HTM. These include the effect of doping density, defect density and thickness of absorber layer, along with the influence of diffusion length of carriers as well as electron affinity of electron transport layer (ETM) and HTM on the performance of PSCs. In addition, hole mobility and doping density of HTM is also investigated. CuI is a p-type inorganic material with low cost and relatively high stability. It is found that concentration of dopant in absorber layer and HTM, the electron affinity of HTM and ETM affect the performance of solar cell minutely, while cell performance improves greatly with the reduction of defect density. Upon optimization of parameters, power conversion efficiency for this device is found to be 21.32%. The result shows that lead-based PSC with CuI as HTM is an efficient system. Enhancing the stability and reduction of defect density are critical factors for future research. These factors can be improved by better fabrication process and proper encapsulation of solar cell.

ACS Applied Materials & Interfaces, 2022

2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)

The materials used in detection of high energy photons are of primary importance in the construct... more The materials used in detection of high energy photons are of primary importance in the construction of efficient, cost effective and sensitive detectors. Current research into Perovskites for solar cell technology has stimulated interest in their potential alternative uses, one of which is in direct photon conversion radiation detectors, owed primarily to their high-Z elemental composition twinned with exceptional charge carrier transport properties. Here, the Perovskite CsPbBr 3 has been synthesised through solution growth. The raw CsPbBr 3 was a granular powder which was formed into disks of 8 mm diameter and 1-2 mm thickness by two methods: 1). the powders were pressed into pellets using a hydraulic press or 2). sealed in a quartz ampoule under vacuum and then melted and quenched to form a polycrystalline solid which was cut to size. Metallic contacts were deposited on the front and back faces to permit charge collection. The results from the pressed devices are promising, particularly given that the production method is cost effective, repeatable and scalable. The solid-from-melt devices show similar performance but further development is required to optimise the production method.

Scientific reports, Jan 28, 2017

In our work, eco-friendly, non-vacuum and low cost Electrostatic Spray Assisted Vapour Deposition... more In our work, eco-friendly, non-vacuum and low cost Electrostatic Spray Assisted Vapour Deposition (ESAVD) method has been used to produce Cu(In,Ga)(S,Se)2 (CIGS) solar cells. Copper (Cu) deficient (Cu/In + Ga = 0.76) CIGS films were designed to avoid the rather dangerous KCN treatment step for the removal of conductive minor phases of Cu2S/Cu2Se. A simple sodium (Na) treatment method was used to modify the morphology and electronic properties of the absorber and it clearly improved the solar cell performance. The SEM and XRD results testified a slightly increase of the grain size and (112) crystal orientation in the Na-incorporated CIGS thin films. From the Mott-schottky results, it can be seen that the functions of the Na treatment in our non-vacuum deposited CIGS are mainly used for defect passivation and reduction of charge recombination. Photovoltaic characteristics and j-V curve demonstrated that the dipping of CIGS films in 0.2 M NaCl solution for 20 minutes followed by seleni...

Sustainability, 2020

Kesterite Cu2ZnSnS4 (CZTS) has attracted attention as an earth-abundant alternative to commercial... more Kesterite Cu2ZnSnS4 (CZTS) has attracted attention as an earth-abundant alternative to commercially successful CIGS solar cells. CZTS exhibits decent optoelectrical properties while having excellent stability on top of being an earth-abundant, low-cost and non-toxic material. Therefore, in recent years, there has been a significant research effort to develop CZTS-based devices. The efficiency of CZTS solar cells reached 12.6% in 2013, and this was a remarkable achievement at the time. However, the efficiency of these devices has been stagnant since then while emerging technologies, most notably perovskite solar cells, keep breaking record after record. Currently, CZTS research focuses on discovering the secrets of material properties that hinder the efficiency of CZTS solar cells while branching out to develop alternative applications for this material. In this review, we summarize the interesting properties of CZTS as well as its promising applications, which include thin-film sola...

ACS Applied Materials & Interfaces, 2021

Narrow-band-gap III−V semiconductor nanowires (NWs) with a suitable band structure and strong lig... more Narrow-band-gap III−V semiconductor nanowires (NWs) with a suitable band structure and strong light-trapping ability are ideal for high-efficiency low-cost solar water-splitting systems. However, due to their nanoscale dimension, they suffer more severe corrosion by the electrolyte solution than the thin-film counterparts. Thus, short-term durability is the major obstacle for using these NWs for practical water-splitting applications. Here, we demonstrated for the first time that a thin layer (∼7 nm thick) of compact TiO 2 deposited by atomic layer deposition can provide robust protection to III−V NWs. The protected GaAs NWs maintain 91.4% of its photoluminescence intensity after 14 months of storage in ambient atmosphere, which suggests the TiO 2 layer is pinhole-free. Working as a photocathode for water splitting, they exhibited a 45% larger photocurrent density compared with unprotected counterparts and a high Faraday efficiency of 91% and can also maintain a record-long highly stable performance among narrow-band-gap III−V NW photoelectrodes; after 67 h photoelectrochemical stability test reaction in a strong acid electrolyte solution (pH = 1), they show no apparent indication of corrosion, which is in stark contrast to the unprotected NWs that fully failed after 35 h. These findings provide an effective way to enhance both stability and performance of III−V NW-based photoelectrodes, which are highly important for practical applications in solar-energy-based water-splitting systems.

Solar Energy Materials and Solar Cells, 2017

Highlights-P-type semiconductor ligand modification of ZnO nanorods for hybrid bulk heterojunctio... more Highlights-P-type semiconductor ligand modification of ZnO nanorods for hybrid bulk heterojunction P3HT:ZnO-Fine tuning of surfactant concentration, solvent and P3HT:ZnO ratio for optimized performance-Improve dispersion of ZnO nanorods inside the polymer blend *Highlights (for review) 1

Polymers, 2022

Pentacene is a well-known conjugated organic molecule with high mobility and a sensitive photo re... more Pentacene is a well-known conjugated organic molecule with high mobility and a sensitive photo response. It is widely used in electronic devices, such as in organic thin-film transistors (OTFTs), organic light-emitting diodes (OLEDs), photodetectors, and smart sensors. With the development of flexible and wearable electronics, the deposition of good-quality pentacene films in large-scale organic electronics at the industrial level has drawn more research attention. Several methods are used to deposit pentacene thin films. The thermal evaporation technique is the most frequently used method for depositing thin films, as it has low contamination rates and a well-controlled deposition rate. Solution-processable methods such as spin coating, dip coating, and inkjet printing have also been widely studied because they enable large-scale deposition and low-cost fabrication of devices. This review summarizes the deposition principles and control parameters of each deposition method for pent...

Molecules

Perovskite solar cells (PSCs) have achieved tremendous success within just a decade. This success... more Perovskite solar cells (PSCs) have achieved tremendous success within just a decade. This success is critically dependent upon compositional engineering, morphology control of perovskite layer, or contingent upon high-temperature annealed mesoporous TiO2, but quantitative analysis of the role of facile TiCl4 treatment and thickness control of the compact TiO2 layer has not been satisfactorily undertaken. Herein, we report the facile thickness control and post-treatment of the electron transport TiO2 layer to produce highly efficient planar PSCs. TiCl4 treatment of TiO2 layer could remove the surface trap and decrease the charge recombination in the prepared solar cells. Introduction of ethanol into the TiCl4 aqueous solution led to further improved open-circuit voltage and short-circuit current density of the related devices, thus giving rise to enhanced power conversion efficiency (PCE). After the optimal TiCl4 treatment, PCE of 16.42% was achieved for PSCs with TiCl4 aqueous solut...

Solar Energy Materials and Solar Cells, 2007

In this work, a new type of dye-sensitized bulk-heterojunction hybrid solar cells has been develo... more In this work, a new type of dye-sensitized bulk-heterojunction hybrid solar cells has been developed. The heterojunction films were prepared to contain poly(3-hexylthiophene) (P3HT), N,N 0-diphenyl glyoxaline-3,4,9,10-perylene tetracarboxylic acid diacidamide (PDI) and TiO 2. In the architecture, TiO 2 and P3HT were designed to act as the electron acceptor and donor. PDI was used as sensitizer to enhance the photon absorption. Results showed that by incorporation of PDI in the P3HT/TiO 2 composite, the light absorption, exciton separation and photocurrent under white light were dramatically enhanced. Solar decay analyses showed that devices contained TiO 2 required 12 h to obtain maximum current density and the addition of PDI did not affect the solar decay behavior and stability of device composed of P3HT/TiO 2. The devices of P3HT, P3HT/TiO 2 , P3HT/TiO 2 /PDI could work for 5, 42, 45 h under continuous white light illumination (100 mW/m 2) under the ambient condition.

ACS applied materials & interfaces, Jan 6, 2016

With record cell efficiency of 21.7%, CIGS solar cells have demonstrated to be a very promising p... more With record cell efficiency of 21.7%, CIGS solar cells have demonstrated to be a very promising photovoltaic (PV) technology. However, their market penetration has been limited due to the inherent high cost of the cells. In this work, to lower the cost of CIGS solar cells, all nonvacuum-processed CIGS solar cells were designed and developed. CIGS absorber was prepared by the annealing of electrodeposited metallic layers in a chalcogen atmosphere. Nonvacuum-deposited Ag nanowires (NWs)/AZO transparent electrodes (TEs) with good transmittance (92.0% at 550 nm) and high conductivity (sheet resistance of 20 Ω/□) were used to replace the vacuum-sputtered window layer. Additional thermal treatment after device preparation was conducted at 220 °C for a few of minutes to improve both the value and the uniformity of the efficiency of CIGS pixel cell on 5 × 5 cm substrate. The best performance of the all-nonvacuum-fabricated CIGS solar cells showed an efficiency of 14.05% with Jsc of 34.82 mA...

Current Applied Physics, 2009

In this article, we describe a new method to prepare a ZnO and conjugated polymer nanocomposite a... more In this article, we describe a new method to prepare a ZnO and conjugated polymer nanocomposite and its application in bulk-heterojunction solar cells. The composite was composed of zinc oxide (ZnO) and poly(phenylene vinylene)/poly(vinyl alcohol) (PPV/PVA). For the preparation, the composite was prepared first through the complex reaction between Zn2+ ion and –OH of the PVA–PPV precursor by simply mixing

Current Applied Physics, 2009

In this article, we describe a new method to prepare a ZnO and conjugated polymer nanocomposite a... more In this article, we describe a new method to prepare a ZnO and conjugated polymer nanocomposite and its application in bulk-heterojunction solar cells. The composite was composed of zinc oxide (ZnO) and poly(phenylene vinylene)/poly(vinyl alcohol) (PPV/PVA). For the preparation, the composite was prepared first through the complex reaction between Zn2+ ion and –OH of the PVA–PPV precursor by simply mixing

Solar Energy Materials and Solar Cells, 2008

This article reports the preparation of three-dimensional (3D) mesoporous zinc oxide (ZnO) films ... more This article reports the preparation of three-dimensional (3D) mesoporous zinc oxide (ZnO) films and their application in solar cells. The films were obtained through electrochemical deposition in DMSO solutions by using PS colloidal crystal as templates. The ZnO films with inverse opal (IO) structure were obtained after removing the templates by thermolysis. The ordered porous ZnO films were used to prepare hybrid solar cells by infiltrating the films with poly(3-hexylthiophene) (P3HT) or P3HT:ZnO nanocomposite. Results showed that the interpenetrating network of both ZnO(IO) and P3HT can form continuous pathways for electron and hole transport. By infiltrating a P3HT:ZnO nanocomposite into the porous ZnO films, the photocurrent of the solar cell can be dramatically improved. The cell shows the V oc and I sc of 462 mV and 444.3 mA/cm 2 , respectively. By using a 420 nm cutoff filter, the cell retains about 80% and 50% of its original V oc and I sc after continuous white-light illumination (100 mW/cm 2) for 10 h. Stability of the device under above conditions was estimated to be 51 h.

ACS applied materials & interfaces, Jan 21, 2015

Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, non-vacuum and ... more Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, non-vacuum and cost-effective Electrostatic Spray-Assisted Vapor Deposition (ESAVD) method. The generation of a fine aerosol of precursor solution, and their controlled deposition onto molybdenum substrate, results in adherent, dense and uniform Cu(In,Ga)S2 (CIGS) films. This is an essential tool to keep the interfacial area of thin film solar cells to a minimum value for efficient charge separation as it helps to achieve the desired surface smoothness uniformity for subsequent cadmium sulfide and window layer deposition. This non-vacuum aerosol based approach for making the CIGSSe film uses environmentally benign precursor solution, and it is cheaper for producing solar cells than that of the vacuum-based thin film solar technology. An optimized CIGSSe thin film solar cell with a device configuration of molybdenum-coated soda-lime glass substrate/CIGSSe/CdS/i-ZnO/AZO shows the photovoltaic (j-V) chara...

Current Applied Physics, 2020

Inverted perovskite solar cells (p-in PSCs) have been fascinated due to rapid progress of perform... more Inverted perovskite solar cells (p-in PSCs) have been fascinated due to rapid progress of performance in recent years. PEDOT: PSS is commonly used hole transport material (HTM) in p-in PSCs which is hygroscopic and acidic in nature that leads towards poor performance of device thus hinders commercialization of PSCs. Therefore, it is necessary to replace PEDOT: PSS with stable HTM in p-in PSCs. In this paper, theoretical study is carried out to investigate various physical parameters that can affect the performance of p-in PSCs with copper iodide (CuI) as HTM and phenyl-C61-butyric acid methyl ester (PCBM) as ETM. These parameters include the effect of doping density of ETM, absorber, and HTM as well as defect density and thickness of absorber on the performance of p-in PSCs. In addition, hole mobility and thickness of HTM is also investigated. It is found that performance of p-in PSC is strongly dependent on defect density and thickness of absorber layer while other physical parameters have minor influence on the performance of device. Upon final optimization, device attains PCE of more than 21 % which is encouraging. These results show that CuI as HTM is a potential choice for p-in PSCs.

CrystEngComm, 2017

Tuning the morphology, composition and photoluminescence emission over almost the entire visible ... more Tuning the morphology, composition and photoluminescence emission over almost the entire visible region of all-inorganic cesium lead halide nanocrystals by a general and facile one-pot synthetic approach.

Semiconductor Science and Technology, 2018

Hole transport material (HTM) plays an important role in the efficiency and stability of perovski... more Hole transport material (HTM) plays an important role in the efficiency and stability of perovskite solar cells (PSCs). Spiro-MeOTAD, the commonly used HTM, is costly and can be easily degraded by heat and moisture, thus offering hindrance to commercialize PSCs. There is dire need to find an alternate inorganic and stable HTM to exploit PSCs with their maximum capability. In this paper, a comprehensive device simulation is used to study various possible parameters that can influence the performance of perovskite solar cell with CuI as HTM. These include the effect of doping density, defect density and thickness of absorber layer, along with the influence of diffusion length of carriers as well as electron affinity of electron transport layer (ETM) and HTM on the performance of PSCs. In addition, hole mobility and doping density of HTM is also investigated. CuI is a p-type inorganic material with low cost and relatively high stability. It is found that concentration of dopant in absorber layer and HTM, the electron affinity of HTM and ETM affect the performance of solar cell minutely, while cell performance improves greatly with the reduction of defect density. Upon optimization of parameters, power conversion efficiency for this device is found to be 21.32%. The result shows that lead-based PSC with CuI as HTM is an efficient system. Enhancing the stability and reduction of defect density are critical factors for future research. These factors can be improved by better fabrication process and proper encapsulation of solar cell.

ACS Applied Materials & Interfaces, 2022

2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)

The materials used in detection of high energy photons are of primary importance in the construct... more The materials used in detection of high energy photons are of primary importance in the construction of efficient, cost effective and sensitive detectors. Current research into Perovskites for solar cell technology has stimulated interest in their potential alternative uses, one of which is in direct photon conversion radiation detectors, owed primarily to their high-Z elemental composition twinned with exceptional charge carrier transport properties. Here, the Perovskite CsPbBr 3 has been synthesised through solution growth. The raw CsPbBr 3 was a granular powder which was formed into disks of 8 mm diameter and 1-2 mm thickness by two methods: 1). the powders were pressed into pellets using a hydraulic press or 2). sealed in a quartz ampoule under vacuum and then melted and quenched to form a polycrystalline solid which was cut to size. Metallic contacts were deposited on the front and back faces to permit charge collection. The results from the pressed devices are promising, particularly given that the production method is cost effective, repeatable and scalable. The solid-from-melt devices show similar performance but further development is required to optimise the production method.

Scientific reports, Jan 28, 2017

In our work, eco-friendly, non-vacuum and low cost Electrostatic Spray Assisted Vapour Deposition... more In our work, eco-friendly, non-vacuum and low cost Electrostatic Spray Assisted Vapour Deposition (ESAVD) method has been used to produce Cu(In,Ga)(S,Se)2 (CIGS) solar cells. Copper (Cu) deficient (Cu/In + Ga = 0.76) CIGS films were designed to avoid the rather dangerous KCN treatment step for the removal of conductive minor phases of Cu2S/Cu2Se. A simple sodium (Na) treatment method was used to modify the morphology and electronic properties of the absorber and it clearly improved the solar cell performance. The SEM and XRD results testified a slightly increase of the grain size and (112) crystal orientation in the Na-incorporated CIGS thin films. From the Mott-schottky results, it can be seen that the functions of the Na treatment in our non-vacuum deposited CIGS are mainly used for defect passivation and reduction of charge recombination. Photovoltaic characteristics and j-V curve demonstrated that the dipping of CIGS films in 0.2 M NaCl solution for 20 minutes followed by seleni...

Sustainability, 2020

Kesterite Cu2ZnSnS4 (CZTS) has attracted attention as an earth-abundant alternative to commercial... more Kesterite Cu2ZnSnS4 (CZTS) has attracted attention as an earth-abundant alternative to commercially successful CIGS solar cells. CZTS exhibits decent optoelectrical properties while having excellent stability on top of being an earth-abundant, low-cost and non-toxic material. Therefore, in recent years, there has been a significant research effort to develop CZTS-based devices. The efficiency of CZTS solar cells reached 12.6% in 2013, and this was a remarkable achievement at the time. However, the efficiency of these devices has been stagnant since then while emerging technologies, most notably perovskite solar cells, keep breaking record after record. Currently, CZTS research focuses on discovering the secrets of material properties that hinder the efficiency of CZTS solar cells while branching out to develop alternative applications for this material. In this review, we summarize the interesting properties of CZTS as well as its promising applications, which include thin-film sola...

ACS Applied Materials & Interfaces, 2021

Narrow-band-gap III−V semiconductor nanowires (NWs) with a suitable band structure and strong lig... more Narrow-band-gap III−V semiconductor nanowires (NWs) with a suitable band structure and strong light-trapping ability are ideal for high-efficiency low-cost solar water-splitting systems. However, due to their nanoscale dimension, they suffer more severe corrosion by the electrolyte solution than the thin-film counterparts. Thus, short-term durability is the major obstacle for using these NWs for practical water-splitting applications. Here, we demonstrated for the first time that a thin layer (∼7 nm thick) of compact TiO 2 deposited by atomic layer deposition can provide robust protection to III−V NWs. The protected GaAs NWs maintain 91.4% of its photoluminescence intensity after 14 months of storage in ambient atmosphere, which suggests the TiO 2 layer is pinhole-free. Working as a photocathode for water splitting, they exhibited a 45% larger photocurrent density compared with unprotected counterparts and a high Faraday efficiency of 91% and can also maintain a record-long highly stable performance among narrow-band-gap III−V NW photoelectrodes; after 67 h photoelectrochemical stability test reaction in a strong acid electrolyte solution (pH = 1), they show no apparent indication of corrosion, which is in stark contrast to the unprotected NWs that fully failed after 35 h. These findings provide an effective way to enhance both stability and performance of III−V NW-based photoelectrodes, which are highly important for practical applications in solar-energy-based water-splitting systems.

Solar Energy Materials and Solar Cells, 2017

Highlights-P-type semiconductor ligand modification of ZnO nanorods for hybrid bulk heterojunctio... more Highlights-P-type semiconductor ligand modification of ZnO nanorods for hybrid bulk heterojunction P3HT:ZnO-Fine tuning of surfactant concentration, solvent and P3HT:ZnO ratio for optimized performance-Improve dispersion of ZnO nanorods inside the polymer blend *Highlights (for review) 1

Polymers, 2022

Pentacene is a well-known conjugated organic molecule with high mobility and a sensitive photo re... more Pentacene is a well-known conjugated organic molecule with high mobility and a sensitive photo response. It is widely used in electronic devices, such as in organic thin-film transistors (OTFTs), organic light-emitting diodes (OLEDs), photodetectors, and smart sensors. With the development of flexible and wearable electronics, the deposition of good-quality pentacene films in large-scale organic electronics at the industrial level has drawn more research attention. Several methods are used to deposit pentacene thin films. The thermal evaporation technique is the most frequently used method for depositing thin films, as it has low contamination rates and a well-controlled deposition rate. Solution-processable methods such as spin coating, dip coating, and inkjet printing have also been widely studied because they enable large-scale deposition and low-cost fabrication of devices. This review summarizes the deposition principles and control parameters of each deposition method for pent...

Molecules

Perovskite solar cells (PSCs) have achieved tremendous success within just a decade. This success... more Perovskite solar cells (PSCs) have achieved tremendous success within just a decade. This success is critically dependent upon compositional engineering, morphology control of perovskite layer, or contingent upon high-temperature annealed mesoporous TiO2, but quantitative analysis of the role of facile TiCl4 treatment and thickness control of the compact TiO2 layer has not been satisfactorily undertaken. Herein, we report the facile thickness control and post-treatment of the electron transport TiO2 layer to produce highly efficient planar PSCs. TiCl4 treatment of TiO2 layer could remove the surface trap and decrease the charge recombination in the prepared solar cells. Introduction of ethanol into the TiCl4 aqueous solution led to further improved open-circuit voltage and short-circuit current density of the related devices, thus giving rise to enhanced power conversion efficiency (PCE). After the optimal TiCl4 treatment, PCE of 16.42% was achieved for PSCs with TiCl4 aqueous solut...

Solar Energy Materials and Solar Cells, 2007

In this work, a new type of dye-sensitized bulk-heterojunction hybrid solar cells has been develo... more In this work, a new type of dye-sensitized bulk-heterojunction hybrid solar cells has been developed. The heterojunction films were prepared to contain poly(3-hexylthiophene) (P3HT), N,N 0-diphenyl glyoxaline-3,4,9,10-perylene tetracarboxylic acid diacidamide (PDI) and TiO 2. In the architecture, TiO 2 and P3HT were designed to act as the electron acceptor and donor. PDI was used as sensitizer to enhance the photon absorption. Results showed that by incorporation of PDI in the P3HT/TiO 2 composite, the light absorption, exciton separation and photocurrent under white light were dramatically enhanced. Solar decay analyses showed that devices contained TiO 2 required 12 h to obtain maximum current density and the addition of PDI did not affect the solar decay behavior and stability of device composed of P3HT/TiO 2. The devices of P3HT, P3HT/TiO 2 , P3HT/TiO 2 /PDI could work for 5, 42, 45 h under continuous white light illumination (100 mW/m 2) under the ambient condition.

ACS applied materials & interfaces, Jan 6, 2016

With record cell efficiency of 21.7%, CIGS solar cells have demonstrated to be a very promising p... more With record cell efficiency of 21.7%, CIGS solar cells have demonstrated to be a very promising photovoltaic (PV) technology. However, their market penetration has been limited due to the inherent high cost of the cells. In this work, to lower the cost of CIGS solar cells, all nonvacuum-processed CIGS solar cells were designed and developed. CIGS absorber was prepared by the annealing of electrodeposited metallic layers in a chalcogen atmosphere. Nonvacuum-deposited Ag nanowires (NWs)/AZO transparent electrodes (TEs) with good transmittance (92.0% at 550 nm) and high conductivity (sheet resistance of 20 Ω/□) were used to replace the vacuum-sputtered window layer. Additional thermal treatment after device preparation was conducted at 220 °C for a few of minutes to improve both the value and the uniformity of the efficiency of CIGS pixel cell on 5 × 5 cm substrate. The best performance of the all-nonvacuum-fabricated CIGS solar cells showed an efficiency of 14.05% with Jsc of 34.82 mA...

Current Applied Physics, 2009

In this article, we describe a new method to prepare a ZnO and conjugated polymer nanocomposite a... more In this article, we describe a new method to prepare a ZnO and conjugated polymer nanocomposite and its application in bulk-heterojunction solar cells. The composite was composed of zinc oxide (ZnO) and poly(phenylene vinylene)/poly(vinyl alcohol) (PPV/PVA). For the preparation, the composite was prepared first through the complex reaction between Zn2+ ion and –OH of the PVA–PPV precursor by simply mixing

Current Applied Physics, 2009

In this article, we describe a new method to prepare a ZnO and conjugated polymer nanocomposite a... more In this article, we describe a new method to prepare a ZnO and conjugated polymer nanocomposite and its application in bulk-heterojunction solar cells. The composite was composed of zinc oxide (ZnO) and poly(phenylene vinylene)/poly(vinyl alcohol) (PPV/PVA). For the preparation, the composite was prepared first through the complex reaction between Zn2+ ion and –OH of the PVA–PPV precursor by simply mixing

Solar Energy Materials and Solar Cells, 2008

This article reports the preparation of three-dimensional (3D) mesoporous zinc oxide (ZnO) films ... more This article reports the preparation of three-dimensional (3D) mesoporous zinc oxide (ZnO) films and their application in solar cells. The films were obtained through electrochemical deposition in DMSO solutions by using PS colloidal crystal as templates. The ZnO films with inverse opal (IO) structure were obtained after removing the templates by thermolysis. The ordered porous ZnO films were used to prepare hybrid solar cells by infiltrating the films with poly(3-hexylthiophene) (P3HT) or P3HT:ZnO nanocomposite. Results showed that the interpenetrating network of both ZnO(IO) and P3HT can form continuous pathways for electron and hole transport. By infiltrating a P3HT:ZnO nanocomposite into the porous ZnO films, the photocurrent of the solar cell can be dramatically improved. The cell shows the V oc and I sc of 462 mV and 444.3 mA/cm 2 , respectively. By using a 420 nm cutoff filter, the cell retains about 80% and 50% of its original V oc and I sc after continuous white-light illumination (100 mW/cm 2) for 10 h. Stability of the device under above conditions was estimated to be 51 h.

ACS applied materials & interfaces, Jan 21, 2015

Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, non-vacuum and ... more Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, non-vacuum and cost-effective Electrostatic Spray-Assisted Vapor Deposition (ESAVD) method. The generation of a fine aerosol of precursor solution, and their controlled deposition onto molybdenum substrate, results in adherent, dense and uniform Cu(In,Ga)S2 (CIGS) films. This is an essential tool to keep the interfacial area of thin film solar cells to a minimum value for efficient charge separation as it helps to achieve the desired surface smoothness uniformity for subsequent cadmium sulfide and window layer deposition. This non-vacuum aerosol based approach for making the CIGSSe film uses environmentally benign precursor solution, and it is cheaper for producing solar cells than that of the vacuum-based thin film solar technology. An optimized CIGSSe thin film solar cell with a device configuration of molybdenum-coated soda-lime glass substrate/CIGSSe/CdS/i-ZnO/AZO shows the photovoltaic (j-V) chara...