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Papers by Mr. Depak Kumar

Research paper thumbnail of Investigations of Lead Free Halides in Sodium Based Double Perovskites Cs2NaBiX6(X=Cl, Br, I): an Ab Intio Study

East European journal of physics, Sep 28, 2021

Despites the excellent merits of lead based perovskite optoelectronic devices; their unstable nat... more Despites the excellent merits of lead based perovskite optoelectronic devices; their unstable nature and toxicity still present a bottleneck for practical applications. Double perovskite has emerged as a candidate for optoelectronics and photovoltaic application because of its nontoxic behaviour and stability in air. We have presented ab-initio study of Cs2NaBiX6(X=Cl, Br, I) lead free halide double perovskites. The calculation is carried out using the FP-LAPW method in the DFT framework within PBE potential using the WIEN2k code. The structural, electronic and optical properties of Cs2NaBiI6, Cs2NaBiBr6 and Cs2NaBiCl6 have been analysed. We have obtained the band gap of 2.0, 2.6 and 3.7 for Cs2NaBiI6, Cs2NaBiBr6 and Cs2NaBiCl6 respectively. Throughout the study, we have shown that the variation in the structure of double perovskite within Cs2NaBiX6(X=Cl, Br, I) that leads to the variation in band gap, density of states and in optical properties such as extinction coefficient, absorption spectra, optical reflectivity, dielectric coefficient, refractive index that shows the variety of this material for optoelectronic devices and other purposes.

Research paper thumbnail of Investigation of Methylammonium Lead Bromide Hybrid Perovskite Based Photoactive Material for the Photovoltaic Applications

Digest Journal of Nanomaterials and Biostructures, 2021

Metal halide perovskites are bringing us closer to the goal of energy self-sufficient buildings. ... more Metal halide perovskites are bringing us closer to the goal of energy self-sufficient buildings. In this paper, we have been prepared device {FTO (Fluorine-doped tin Oxide)/CH 3 NH 3 PbBr 3 /Spiro-OMeTAD/Al} of by using methyl amine lead bromide base as photoactive materials for the photovoltaic applications, and then investigate the parameters involved. In order to fabricate, low-temperature solution-processed devices using one-step spin coating methods play a key role in producing uniform thin films. The spin coating technique has been used for the deposition of the precursor solution including methylammonium bromide (MABr) and lead bromide (PbBr 2) with molar ratio (3:1) to prepare the thin films onto FTO-substrate. The topographical studies of the thin films prepared have been done by field emission scanning electron microscopy (FESEM). Furthermore, the required parameters of the device such as; ideality factor, barrier height, saturation current, carrier mobility, current density, resistance, capacitance and carrier lifetime have been calculated by current-voltage(I-V) characteristics and Impedance Spectroscopy technique. The device was irradiated by a laser of power 20mW functioning at wavelength of 532nm. At low voltage the current conduction mechanism displays Ohmic behavior and trap free space charge limited conduction (TFSCLC) controls the charge transport at mid voltages. While trap controlled space charge limited conduction (TCSCLC) reveals at high voltages. The hole mobility has been estimated by TCSCLC model.

Research paper thumbnail of Synthesis and Characterization of Methylammonium Lead Bromide Perovskite Based Photovoltaic Device

East European journal of physics, Sep 28, 2021

Hybrid electronic devices give a reasonable path for feasible power sources and other further app... more Hybrid electronic devices give a reasonable path for feasible power sources and other further applications due to its easy arrangement, preparation, producing, ease of materials, and less environmental impact. In this paper, we have discussed electrical properties of hybrid bromide perovskite nanoparticles and current progressions in perovskite photovoltaic devices have also been discussed. In order to fabricate, low-temperature solution-processed devices using one-step spin coating methods play a key role in producing uniform thin films. The spin coating technique has been used for the deposition of the precursor solution including methylammonium bromide (MABr) and lead bromide (PbBr2) with molar ratio (3:1) to prepare the thin films onto FTO-substrate. One-step solution processes has been used for deposition of the CH3NH3PbBr3 absorber layers and have explained an overview of material composition, deposition technique and the architecture of the device, the selection of charge transport layer and electrode.

Research paper thumbnail of Review on E-waste management and its impact on the environment and society

Waste Management Bulletin

Research paper thumbnail of Investigations of Lead Free Halides in Sodium Based Double Perovskites Cs2NaBiX6(X=Cl, Br, I): an Ab Intio Study

3

Despites the excellent merits of lead based perovskite optoelectronic devices; their unstable nat... more Despites the excellent merits of lead based perovskite optoelectronic devices; their unstable nature and toxicity still present a bottleneck for practical applications. Double perovskite has emerged as a candidate for optoelectronics and photovoltaic application because of its nontoxic behaviour and stability in air. We have presented ab-initio study of Cs2NaBiX6(X=Cl, Br, I) lead free halide double perovskites. The calculation is carried out using the FP-LAPW method in the DFT framework within PBE potential using the WIEN2k code. The structural, electronic and optical properties of Cs2NaBiI6, Cs2NaBiBr6 and Cs2NaBiCl6 have been analysed. We have obtained the band gap of 2.0, 2.6 and 3.7 for Cs2NaBiI6, Cs2NaBiBr6 and Cs2NaBiCl6 respectively. Throughout the study, we have shown that the variation in the structure of double perovskite within Cs2NaBiX6(X=Cl, Br, I) that leads to the variation in band gap, density of states and in optical properties such as extinction coefficient, absor...

Research paper thumbnail of Delignification of black liquor from sunn hemp fibre

The book concern with delignification of of black liquor with cook and pulp process from Crotalar... more The book concern with delignification of of black liquor with cook and pulp process from Crotalaria juncea (sunn hemp) fibre. Lignocellulose is the most abundant biomass, representing nearly 70% of the total plant biomass. The removal of the structural polymer lignin from plant tissue is known as Delignification which can be used for applications i.e. paper making. The chemical and mechanical process are used for the removal of pulp from wood.

Research paper thumbnail of Coal Combustion and C Programme

In by-product coke oven battery, pulverized coal blend cake is carbonized in a series of coking c... more In by-product coke oven battery, pulverized coal blend cake is carbonized in a series of coking chambers. Each cake of coal blend is contained between two heating walls in which number of inverted U-shaped flue ducts are embedded. Heat generated due to combustion of gaseous fuel in the flue duct is utilized for carbonization of coal. As the direction of flue gas changes periodically after every 30 min, and the twin coal beds on either side of heating wall are at 10 h heating lag, thermal dynamics set in the gas and walls. Numerical study of process transients reveals that positional gas temperature in the flue duct oscillates with flow reversal. The maximum and minimum temperatures show a rising trend with flow reversal during coking cycle. The temperature at the inner walls and outer walls of the flue duct show periodic rise and fall with the flow reversal, and show drastic drop at the time coke is pushed out. Similar characteristics are observed for wall surfaces facing coke bed, ...

Research paper thumbnail of Investigations of Lead Free Halides in Sodium Based Double Perovskites Cs2NaBiX6(X=Cl, Br, I): an Ab Intio Study

East European journal of physics, Sep 28, 2021

Despites the excellent merits of lead based perovskite optoelectronic devices; their unstable nat... more Despites the excellent merits of lead based perovskite optoelectronic devices; their unstable nature and toxicity still present a bottleneck for practical applications. Double perovskite has emerged as a candidate for optoelectronics and photovoltaic application because of its nontoxic behaviour and stability in air. We have presented ab-initio study of Cs2NaBiX6(X=Cl, Br, I) lead free halide double perovskites. The calculation is carried out using the FP-LAPW method in the DFT framework within PBE potential using the WIEN2k code. The structural, electronic and optical properties of Cs2NaBiI6, Cs2NaBiBr6 and Cs2NaBiCl6 have been analysed. We have obtained the band gap of 2.0, 2.6 and 3.7 for Cs2NaBiI6, Cs2NaBiBr6 and Cs2NaBiCl6 respectively. Throughout the study, we have shown that the variation in the structure of double perovskite within Cs2NaBiX6(X=Cl, Br, I) that leads to the variation in band gap, density of states and in optical properties such as extinction coefficient, absorption spectra, optical reflectivity, dielectric coefficient, refractive index that shows the variety of this material for optoelectronic devices and other purposes.

Research paper thumbnail of Investigation of Methylammonium Lead Bromide Hybrid Perovskite Based Photoactive Material for the Photovoltaic Applications

Digest Journal of Nanomaterials and Biostructures, 2021

Metal halide perovskites are bringing us closer to the goal of energy self-sufficient buildings. ... more Metal halide perovskites are bringing us closer to the goal of energy self-sufficient buildings. In this paper, we have been prepared device {FTO (Fluorine-doped tin Oxide)/CH 3 NH 3 PbBr 3 /Spiro-OMeTAD/Al} of by using methyl amine lead bromide base as photoactive materials for the photovoltaic applications, and then investigate the parameters involved. In order to fabricate, low-temperature solution-processed devices using one-step spin coating methods play a key role in producing uniform thin films. The spin coating technique has been used for the deposition of the precursor solution including methylammonium bromide (MABr) and lead bromide (PbBr 2) with molar ratio (3:1) to prepare the thin films onto FTO-substrate. The topographical studies of the thin films prepared have been done by field emission scanning electron microscopy (FESEM). Furthermore, the required parameters of the device such as; ideality factor, barrier height, saturation current, carrier mobility, current density, resistance, capacitance and carrier lifetime have been calculated by current-voltage(I-V) characteristics and Impedance Spectroscopy technique. The device was irradiated by a laser of power 20mW functioning at wavelength of 532nm. At low voltage the current conduction mechanism displays Ohmic behavior and trap free space charge limited conduction (TFSCLC) controls the charge transport at mid voltages. While trap controlled space charge limited conduction (TCSCLC) reveals at high voltages. The hole mobility has been estimated by TCSCLC model.

Research paper thumbnail of Synthesis and Characterization of Methylammonium Lead Bromide Perovskite Based Photovoltaic Device

East European journal of physics, Sep 28, 2021

Hybrid electronic devices give a reasonable path for feasible power sources and other further app... more Hybrid electronic devices give a reasonable path for feasible power sources and other further applications due to its easy arrangement, preparation, producing, ease of materials, and less environmental impact. In this paper, we have discussed electrical properties of hybrid bromide perovskite nanoparticles and current progressions in perovskite photovoltaic devices have also been discussed. In order to fabricate, low-temperature solution-processed devices using one-step spin coating methods play a key role in producing uniform thin films. The spin coating technique has been used for the deposition of the precursor solution including methylammonium bromide (MABr) and lead bromide (PbBr2) with molar ratio (3:1) to prepare the thin films onto FTO-substrate. One-step solution processes has been used for deposition of the CH3NH3PbBr3 absorber layers and have explained an overview of material composition, deposition technique and the architecture of the device, the selection of charge transport layer and electrode.

Research paper thumbnail of Review on E-waste management and its impact on the environment and society

Waste Management Bulletin

Research paper thumbnail of Investigations of Lead Free Halides in Sodium Based Double Perovskites Cs2NaBiX6(X=Cl, Br, I): an Ab Intio Study

3

Despites the excellent merits of lead based perovskite optoelectronic devices; their unstable nat... more Despites the excellent merits of lead based perovskite optoelectronic devices; their unstable nature and toxicity still present a bottleneck for practical applications. Double perovskite has emerged as a candidate for optoelectronics and photovoltaic application because of its nontoxic behaviour and stability in air. We have presented ab-initio study of Cs2NaBiX6(X=Cl, Br, I) lead free halide double perovskites. The calculation is carried out using the FP-LAPW method in the DFT framework within PBE potential using the WIEN2k code. The structural, electronic and optical properties of Cs2NaBiI6, Cs2NaBiBr6 and Cs2NaBiCl6 have been analysed. We have obtained the band gap of 2.0, 2.6 and 3.7 for Cs2NaBiI6, Cs2NaBiBr6 and Cs2NaBiCl6 respectively. Throughout the study, we have shown that the variation in the structure of double perovskite within Cs2NaBiX6(X=Cl, Br, I) that leads to the variation in band gap, density of states and in optical properties such as extinction coefficient, absor...

Research paper thumbnail of Delignification of black liquor from sunn hemp fibre

The book concern with delignification of of black liquor with cook and pulp process from Crotalar... more The book concern with delignification of of black liquor with cook and pulp process from Crotalaria juncea (sunn hemp) fibre. Lignocellulose is the most abundant biomass, representing nearly 70% of the total plant biomass. The removal of the structural polymer lignin from plant tissue is known as Delignification which can be used for applications i.e. paper making. The chemical and mechanical process are used for the removal of pulp from wood.

Research paper thumbnail of Coal Combustion and C Programme

In by-product coke oven battery, pulverized coal blend cake is carbonized in a series of coking c... more In by-product coke oven battery, pulverized coal blend cake is carbonized in a series of coking chambers. Each cake of coal blend is contained between two heating walls in which number of inverted U-shaped flue ducts are embedded. Heat generated due to combustion of gaseous fuel in the flue duct is utilized for carbonization of coal. As the direction of flue gas changes periodically after every 30 min, and the twin coal beds on either side of heating wall are at 10 h heating lag, thermal dynamics set in the gas and walls. Numerical study of process transients reveals that positional gas temperature in the flue duct oscillates with flow reversal. The maximum and minimum temperatures show a rising trend with flow reversal during coking cycle. The temperature at the inner walls and outer walls of the flue duct show periodic rise and fall with the flow reversal, and show drastic drop at the time coke is pushed out. Similar characteristics are observed for wall surfaces facing coke bed, ...