D. Haranath | Council for Scientific and Industrial Research (CSIR) (original) (raw)

D. Haranath

Dr D Haranath is currently working as Associate Professor in Physics at National Institute of Technology Warangal, India. Earlier to that he served as Principal Scientist at CSIR-National Physical Laboratory, New Delhi for 20 years. He is recipient of many awards and honors in Physical Sciences including NPL's Young Scientist Award in 2003, CSIR Young Scientist Award in 2004, DST's BOYSCAST Fellow Award in Physical Sciences in 2006, VIRA Distinguished Scientist of the year 2016, Fellow of Luminescence Society of India in 2017, Academic Audit Member of VNIT (Nagpur)-2017, Transfer of Technology Award (2018), Fellow of Luminescence Society of India (2018), Visiting Scientist for Nanotheranostics Inc.- USA (2019-2024), Grassroot Innovators Virtual Mela Award (2020) etc. Recently, with the support of Prof D Dinakar, HoD Physics, NIT Warangal he has developed an unique virus disinfectant system called “All-in-One OzoNIT”, which can kill all types of viruses without involvement of hazardous chemicals within few minutes. This was well appreciated by Ministry of Electronics and IT (MeITy, Govt of India). His Post-Doctoral experience gained at Nanocrystals Technology, NY, USA for many years and thereafter visits as Visiting Scientist had enriched him for the synthesis and characterization of Binary and Ternary Nanophosphors for white-LED applications. While at CSIR-NPL, he actively led the Alternative Energy Materials group with an aim of developing novel nanophosphor systems and devices for various strategic applications. He has licensed a yellow-green emitting afterglow phosphor material in Sept-2016 to an Indian paint industry called M/s Kataline Infra Products Pvt Ltd., Nagpur for Rs.11.50 Lakhs. Before to that he and his team of scientists had the credit of transferring TWO more technologies (Sulfide-based afterglow phosphor & X-ray real-time imaging screens) to Defence Laboratory Jodhpur (DRDO) and ONE technology of AC driven Electroluminescent Panels to ISRO. His other R&D interests are positioned in the synthesis and characterization of nanophase luminescent materials for LEDs and spectral energy conversion in silicon solar cells; fabrication of electroluminescent panels for back-lighting of LCD panels; development of primary color (RGB) emitting long persistent phosphors for dark vision display applications; development of radioluminescent screens for high energy (80 MeV) X-ray real-time imaging and bio-medical applications of nanophosphors as well. He has a vast research experience of 26 years and supervised 6-Ph.D., 2-M.Phil. and 25-M.Tech. theses. He has 6-granted patents, 3-filed patents, 13-chapters in Books, more than 180 research papers in SCI journals of repute, 25-virtual journal papers, more than 200 national and international conference papers, 3-general articles, 2-technical reports to his credit. Many of his research papers were cited by Nature, appreciated by nanotechweb.org, verticalnews.com, highbeam.com etc. He is also an Editorial Board Member for International Journal of Luminescence and Applications (ISBN: 81-6717-806-5) and reviewer to many international journals viz. RSC, APS, AIP, Wiley, IoP, Springer and Elsevier Sciences. His research credentials as reported by Google Scholar are: h-index: 37, i10-index: 102, citations: 4666. He has handled more than Rs. 3.00 Crores worth of sponsored research projects sponsored by SERB-DST, DAE-BRNS, DRDO, CSIR and MHRD. With the support of his colleague, he and Dr Abdul Azeem together defended before the committee and successful in bringing DST-FIST project worth Rs.2.75 Crores to the Physics Department, NIT Warangal for the procurement of XRD and FE-SEM machines.
Supervisors: Supervisor, Guide, and Mentor

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Papers by D. Haranath

Journal of Alloys and Compounds, 2017

studies of Pr 3+ doped lithium lead alumino borate glasses for visible reddish orange luminescent... more studies of Pr 3+ doped lithium lead alumino borate glasses for visible reddish orange luminescent device applications,

Journal of Physics and Chemistry of Solids, 2018

Europium (Eu) doped LiF crystals have been grown by the Edge-defined film fed growth (EFG) techni... more Europium (Eu) doped LiF crystals have been grown by the Edge-defined film fed growth (EFG) technique. The designing and installation of the furnace used for the growth of the crystals have been discussed in detail. In the present study, Eu (Eu 2 O 3) has been doped in LiF in different concentration (0.02-0.2wt %). X-ray diffractometry (XRD) and Energy Dispersive X-ray (EDX) spectroscopy confirms the incorporation of Eu in LiF. The influence of Eu on LiF has been investigated through photoluminescence (PL), thermoluminescence (TL) and electron paramagnetic resonance (EPR) in as-grown and annealed crystals. PL emission spectra shows the presence of both Eu 3+ and Eu 2+ form in the as-grown crystals which is confirmed by EPR results. Whereas, in annealed crystals, Eu is present predominantly as Eu 2+ form. This suggests that growing crystals at high temperature (~900 o C) in argon gas atmosphere through EFG technique favours the reduction of Eu 3+ → Eu 2+. This reduction phenomenon has been explained on the basis of charge compensation model. TL study of the LiF: Eu (0.02-0.2wt %) crystals has been done after irradiation with Co 60 gamma rays. In this study, it has been observed that the TL intensity as well as glow curve structure of LiF: Eu crystals are a strong function of Eu concentration. The maximum TL is observed at Eu concentration of 0.05wt% at which a well defined glow curve structure with a prominent peak at 185 o C and a small peak at 253 o C. Beyond this concentration (0.05wt %), TL intensity decreases due to aggregation of defects in the host. The peak at 185 o C in LiF: Eu (0.05wt %) is certainly due to the presence of Eu 2+ associated defects which is also supported by the PL spectra. It has been observed that Eu doping have a key role in creation of more defect levels which lead to the increased number of electron and hole traps. Further, trapping parameters are analysed using glow curve deconvolution method to have an insight study of TL phenomena. Further, TL glow curve structure of as-grown and annealed crystal are distinct which may be attributed to the nature of defect traps formed inside the LiF.

Saudi Journal of Biological Sciences, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Current Applied Physics, 2017

Journal of Nanoscience and Nanotechnology, 2020

A new self-activated green-yellow emitting Gd2CaZnO5 (GCZO) phosphor was synthesized using solid-... more A new self-activated green-yellow emitting Gd2CaZnO5 (GCZO) phosphor was synthesized using solid-state reaction method at high-temperature. XRD analysis confirmed the orthorhombic structure of the sample with the Pbnm space group. SEM micrographs reveal the irregular morphology with micron sized particles. Detailed photoluminescence (PL) analysis revealed that the excitation of the phosphor lies in the UV range (˜377 nm) with the related broad green-yellow emission centered at 530 nm. The broad band emission ranging from ˜450 nm to 650 nm can be attributed to the surface defects and oxygen vacancies. The calculated luminescence decay lifetime for the optimized phosphor was found to be 2.925 μs. Furthermore, the color-coordinate (x, y) were calculated and found to be (0.44, 0.45), which lies in the green-yellow (˜540 nm) region of the electromagnetic spectrum. The values of color coordinates and Color correlated temperature of 3289 K support the synthesized phosphor for the emission ...

Sensors and Actuators A: Physical, 2021

Nanotechnology, 2020

Red emitting (~ 612 nm) CaTiO3:Pr3+ long afterglow nanocrystals with a persistence time for more ... more Red emitting (~ 612 nm) CaTiO3:Pr3+ long afterglow nanocrystals with a persistence time for more than 20 minutes (dark adapted human eyes) have been synthesised for developing high contrast latent fingerprints via sol-gel process. Due the persistent emission, CaTiO3:Pr3+ nanophosphor does not require continuous source for excitation, thereby eliminating the background information even from multi-colour substrate, resulting into high signal to noise ratio. As a consequence of which minutiae features of level- I, II and III can be cleared studied in high contrast fingerprints. Considerable blue shift (~ 20 nm) was recorded in photoluminescence excitation due to the quantum confinement properties of CaTiO3: Pr3+ nanocrystals. Powder XRD confirms the formation of single phase orthorhombic structure of CaTiO3: Pr3+ with average crystallite size ~ 40 nm. Spectral parameters indicate very high color purity of 99% with CIE coordinates (0.62, 0.37) which are very close to NTSC standards for an ideal red-emission. TEM studies confirm the formation of spherical particles with narrow size distribution which makes them suitable to combine with fingerprint development methods such as powder dusting and cyanoacrylate fuming methods.

Optik, 2019

Recent studies have shown that, Eu 3+ doped silicates have gained lot of importance as an ideal r... more Recent studies have shown that, Eu 3+ doped silicates have gained lot of importance as an ideal red phosphor material in White Light Emitting Diode (WLED) application, due to Eu 3+ electronic configuration. Studies have been carried out in the literature to observe the effect of charge compensation on photoluminescence properties of silicates. Alkali metals (Li + , Na + , K + , Cl-) and other halogens are used as charge compensators. The Li + ion is known to be a good charge compensator because of its small size and such studies are well documented. Keeping this in view, we wanted to carry out such compensation using alkali metals but also curious to understand, the way a combination of alkali pair for such compensation process and the effect of charge compensator on the PL properties of this phosphor. We specifically chose the alkali pair, where charges are same but their size and mass ratio being vastly different. Europium doped calcium silicate (Ca2SiO4: Eu 3+) has been prepared with charge compensators using alkali metals such as Li, Rb and Li-Rb. To start with, β-dicalcium silicate

Physical review. E, 2018

In this paper, we have investigated the behavior of mesogens at smectic-C*-water interface confin... more In this paper, we have investigated the behavior of mesogens at smectic-C*-water interface confined in a liquid crystal (LC) cell with interfacial geometry. Polarized optical microscopy was used to probe the appearance of various smectic-C* domain patterns at water interface owing to the reorientation of mesogens. The undulated stripe domains observed at the air interface of smectic-C* meniscus vanished as the water entered into the smectic layers and focal conical domain patterns appeared at smectic-C*-water boundary. A spatially variable electro-optical switching of LC molecules was also observed outside the electrode area of the interfacial cell. The electrode region at the interface, as well as on the water side, was damaged upon application of an electric field of magnitude more than 150 kV/m. The change in dielectric parameters of mesogens was extensively studied at interface after evaporating the water. These studies give fundamental insights into smectic-C*-water interface a...

Journal of Applied Crystallography, 2017

This paper reports the detailed synthesis mechanism and the structural, morphological and optical... more This paper reports the detailed synthesis mechanism and the structural, morphological and optical characterization of ultraviolet (∼311 nm) excitable samarium doped gadolinium yttrium orthovanadate, (Gd,Y)VO4:Sm3+, nanocrystals. X-ray diffraction and Rietveld refinement studies confirmed that the synthesized samples crystallize in a tetragonal structure with I41/amd space group. The enhanced photoluminescence intensity of (Gd,Y)VO4:Sm3+ compared with the existing YVO4:Sm3+ phosphor clearly indicates the significant role of Gd3+ ions. This has been attributed to the sensitization of the 6 P J energy level of Gd3+ ions by energy transfer from orthovanadate (VO4 3−) ions and subsequent energy trapping by Sm3+ ions. The energy transfer from VO4 3− to Sm3+ via Gd3+ ions as intermediates and concentration quenching of Gd3+ luminescence are discussed in detail. The optical band gap of the as-prepared nanocrystals has been estimated using UV–vis–NIR absorption spectroscopy, which reveals a ...

Materials Science and Technology, 1998

ABSTRACT

Organic Electronics, 2016

We report high photovoltaic efficiency of over 9% in solution-processed, small-molecule (SPSM) 7,... more We report high photovoltaic efficiency of over 9% in solution-processed, small-molecule (SPSM) 7,7 0-(4,4bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b 0 ]dithiophene-2,6-diyl)bis(6-fluoro-4(5 0-hexyl-[2,2 0-bithiophen]-5-yl)benzo[c]1,2,5]thiadiazole) p-DTS(FBTTh 2) 2 :[6-6]-phenyl C70 butyric acid methyl ester (PC 70 BM) blend based inverted BHJ solar cell by incorporating luminescent zinc oxide doped with sodium (ZnO:Na) quantum dots (QD) (L-ZnO) as a cathode buffer layer (CBL) in inverted bulk-heterojunction (BHJ) solar cells for the first time. The L-ZnO absorbs ultraviolet (UV) light and down-converts it to visible light. The L-ZnO layer's emission overlaps significantly with the absorption of p-DTS(FBTTh 2) 2 , leading to an enhanced absorption by p-DTS(FBTTh 2) 2. This resulted in a significant enhancement of photo-current from 15.4 to 17.27 mA/cm 2 and efficiency from 8% to 9.2% for ZnO and L-ZnO based devices, respectively. This is among one of the highest efficiency values reported so far in the case of SPSM based single junction BHJ solar cells. The luminescent ZnO layer also protects the active layer from UV-induced degradation as solar cells show high stability under constant solar light illumination retaining more than 90% (~28 h) of its initial efficiency, whereas BHJ solar cells without the luminescent ZnO layer degraded to~50% of its initial value under same conditions. Since ZnO is an essential part of inverted organic solar cells, the luminescent L-ZnO CBL has great potential in inverted organic solar cells.

International Journal of Nanoscience, 2015

Nanostructured Al -doped ZnO (AZO) films are deposited on glass substrates by electroless deposit... more Nanostructured Al -doped ZnO (AZO) films are deposited on glass substrates by electroless deposition technique in the present work. AZO films with Al concentration from 1 at.% to 5 at.% are investigated for their structural and morphological properties by X-ray diffraction (XRD), and atomic force microscopy (AFM). An excellent homogeneity is achieved with average crystallite sizes of below 32 nm and a nearly constant root mean square (RMS) surface roughness between 1 nm and 3 nm, for various Al doping concentrations. These smooth and uniform films are characterized for their optical and photoluminescence (PL) properties. A higher value of average transparency between 79% and 92% in the wavelength range of 300–800 nm is achieved, and the PL intensity is found to be a strong function of doping. Density functional theory (DFT) calculations agree with the measured transmittance values, in addition to their predicted electronic structure. Moreover, time-resolved PL measurements indicate ...

Applied Surface Science, 2015

Present work focuses on the influence of various fuels during synthesis and thereafter improvemen... more Present work focuses on the influence of various fuels during synthesis and thereafter improvement in the luminescence decay characteristics under various illuminant irradiations of long afterglow nanophosphors for effective use in dark-vision display applications. The underlying mechanism has also been discussed using trapping and detrapping model.

Series in Optics and Optoelectronics, 2004