Ashique Kotta

Synergistic strategies to unveil the dual influence of additive and annealing treatment on the morphology of isatin-derived low bandgap small molecule donor in solution-processed organic solar cells

Synthetic metals, Aug 1, 2024

Imidazoanthraquinone Derivative as a Surface Passivator for Enhanced and Stable Perovskite Solar Cells

ACS omega, Mar 4, 2024

Effect of donor groups on the photovoltaic performance of benzothiadiazole-core substituted small molecules for fullerene-based bulk heterojunction organic solar cells

Synthetic Metals, Apr 1, 2023

Linear-Shaped Low-Bandgap Asymmetric Conjugated Donor Molecule for Fabrication of Bulk Heterojunction Small-Molecule Organic Solar Cells

Molecules, Feb 5, 2023

A linear-shaped small organic molecule (E)-4-(5-(3,5-dimethoxy-styryl)thiophen-2-yl)-7-(5 -hexyl-... more A linear-shaped small organic molecule (E)-4-(5-(3,5-dimethoxy-styryl)thiophen-2-yl)-7-(5 -hexyl-[2,2 :5 ,2 -terthiophen]-5-yl)benzo [c][1,2,5]thiadiazole (MBTR) comprising a benzothiadiazole (BTD) acceptor linked with the terminal donors bithiophene and dimethoxy vinylbenzene through a π-bridge thiophene was synthesized and analyzed. The MBTR efficiently tuned the thermal, absorption, and emission characteristics to enhance the molecular packing and aggregation behaviors in the solid state. The obtained optical bandgap of 1.86 eV and low-lying highest occupied molecular orbital (HOMO) level of -5.42 eV efficiently lowered the energy losses in the fabricated devices, thereby achieving enhanced photovoltaic performances. The optimized MBTR:PC 71 BM (1:2.5 w/w%) fullerene-based devices showed a maximum power conversion efficiency (PCE) of 7.05%, with an open-circuit voltage (V OC ) of 0.943 V, short-circuit current density (J SC ) of 12.63 mA/cm 2 , and fill factor (FF) of 59.2%. With the addition of 3% 1,8-diiodooctane (DIO), the PCE improved to 8.76% with a high V OC of 1.02 V, J SC of 13.78 mA/cm 2 , and FF of 62.3%, which are associated with improved charge transport at the donor/acceptor interfaces owing to the fibrous active layer morphology and favorable phase separation. These results demonstrate that the introduction of suitable donor/acceptor groups in molecular design and device engineering is an effective approach to enhancing the photovoltaic performances of organic solar cells.

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Effect of donor groups on the photovoltaic performance of benzothiadiazole-core substituted small molecules for fullerene-based bulk heterojunction organic solar cells

Synthetic Metals

Linear-Shaped Low-Bandgap Asymmetric Conjugated Donor Molecule for Fabrication of Bulk Heterojunction Small-Molecule Organic Solar Cells

Molecules

A linear–shaped small organic molecule (E)-4-(5-(3,5-dimethoxy-styryl)thiophen-2-yl)-7-(5″-hexyl-... more A linear–shaped small organic molecule (E)-4-(5-(3,5-dimethoxy-styryl)thiophen-2-yl)-7-(5″-hexyl-[2,2′:5′,2″-terthiophen]-5-yl)benzo[c][1,2,5]thiadiazole (MBTR) comprising a benzothiadiazole (BTD) acceptor linked with the terminal donors bithiophene and dimethoxy vinylbenzene through a π-bridge thiophene was synthesized and analyzed. The MBTR efficiently tuned the thermal, absorption, and emission characteristics to enhance the molecular packing and aggregation behaviors in the solid state. The obtained optical bandgap of 1.86 eV and low-lying highest occupied molecular orbital (HOMO) level of −5.42 eV efficiently lowered the energy losses in the fabricated devices, thereby achieving enhanced photovoltaic performances. The optimized MBTR:PC71BM (1:2.5 w/w%) fullerene-based devices showed a maximum power conversion efficiency (PCE) of 7.05%, with an open-circuit voltage (VOC) of 0.943 V, short-circuit current density (JSC) of 12.63 mA/cm2, and fill factor (FF) of 59.2%. With the addi...

format_quoteBHJ organic solar cells exhibit significant application potential for high energy throughput due to recent advancements in materials and structuring.format_quote

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Room-temperature processed hole-transport layer in flexible inverted perovskite solar cell module

Chemical Engineering Journal, 2022

Integration of Photocharging Perovskite Solar Cells-Lithium Ion Battery (PSC-LIB) System

ECS Meeting Abstracts, 2021

Simple Additive to MAPbI3 Solution that Enhances Film Quality of Mini‐Module Perovskite Solar Cells Fabricated under Moderate Humidity

Solar RRL, 2021

An additive to perovskite material can play a crucial role in the fabrication of perovskite solar... more An additive to perovskite material can play a crucial role in the fabrication of perovskite solar cells (PSCs); the additive treatment investigated herein produces promising overall power conversion efficiency (PCE) enhancements. Currently, the fabrication of PSCs is mainly carried out under the dry air of a glove box to avoid moisture adsorption by methylammonium lead iodide perovskites; these tight restrictions in how PSCs are fabricated hinder the possibility of their commercialization. In this study, a technique that uses C12F4N4 as an additive to the MAPbI3 for the one‐step deposition of perovskite layers under moderate humidity is presented; this approach is able to achieve high‐quality perovskite films despite the adverse condition. The added C12F4N4 bridges the gaps between the MAPbI3 grain boundaries and significantly enhances all the photovoltaic parameters compared to using pristine methylammonium lead iodide; this method even eventually enhances the overall PCE. Both, si...

Communication—Ultra-Small NiO Nanoparticles Grown by Low-Temperature Process for Electrochemical Application

Journal of The Electrochemical Society, 2020

In this paper, we report a size-controlled metal oxide under a low-temperature process for the fa... more In this paper, we report a size-controlled metal oxide under a low-temperature process for the fabrication of an electrochemical sensor based on ultra-small nickel oxide (NiO) nanoparticles (NPs) which are utilized as electrode materials for the detection of n-butylamine chemical. The small size effect (∼6 ± 0.5 nm) and richness of Ni3+ ion concentration of as-synthesized ultra-small NiO nanoparticles exhibited high and reproducible sensitivity of ∼9.51 mA·mM−1·cm−2, limit of detection (LOD) ∼144.21 μM and correlation coefficient (R) ∼ 0.9688 with improved linearity in the range of 100 nM−100 μM.

Effect of V-Incorporated NiO Hole Transport Layer on the Performance of Inverted Perovskite Solar Cells

Materials Proceedings, 2020

Organic–inorganic hybrid perovskite solar cells have resulted in tremendous interest in developin... more Organic–inorganic hybrid perovskite solar cells have resulted in tremendous interest in developing future generation solar cells, due to their high efficiency exceeding 25%. For inverted type perovskite solar cells, the hole transporting layer plays a crucial role in improving the efficiency and stability of the perovskite solar cells by modifying band alignment, electric conductivity, and interfacial recombination losses. Here, vanadium doped NiO is selected as a hole transporting layer to study the impact of V dopant on the optoelectronic properties of NiO and photovoltaic performance. The prepared materials are characterized using XRD, SEM, TEM, and XPS. A TEM micrograph confirms that p-type materials have a small spherical dot structure. The V-doped NiO, used as a hole-extraction layer, can be prepared by a simple solvothermal decomposition method. The presence of V in the NiO layer has an influence on the conductivity of the NiO layer. Besides, synthesized p-type material can b...

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Facile Synthesis of Highly Conductive Vanadium Doped NiO Film for Transparent Conductive Oxide

Metal oxide based electrodes play a crucial role in various as a transparent conductive oxide (TC... more Metal oxide based electrodes play a crucial role in various as a transparent conductive oxide (TCO). One of the metal oxides, nickel oxide is a promising electrical conductive material. Here, we display that incorporation of vanadium in NiO lattice significantly improve both electrical conductivity and hole extraction. Also, vanadium doped nickel oxide exhibits a lower crystalline size compared to pristine nickel oxide, which maintains the reduction of surface roughness. These results indicating that the vanadium is an excellent dopant for NiO.

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Nickel Oxide Monodispersed Quantum Dots as Hole Transport Layer in n–i–p Hybrid Perovskite Solar Cells

Journal of Nanoelectronics and Optoelectronics, 2019

In this work NiO monodispersed quantum dots (QDs) were synthesized by the reduction of nickel (II... more In this work NiO monodispersed quantum dots (QDs) were synthesized by the reduction of nickel (II) acety-lacetonate with the borane-trimethylamine complex in a mixture of oleylamine, which acted as capping agent and helped to control the particle size growth. These were then used as a hole transport layer in regular (n-i-p) type organic-inorganic hybrid perovskite solar cells. Morphology of the NiO QDs was observed with Field emission electron microscope (FESEM) and high resolution transmission electron microscope (HR-TEM) that revealed a monodispersed particles of an average particle size of about 5.5 ± 0.5 nm with distinct lattice fringes (spacing of 0.24 nm). A solar cell was fabricated on FTO glass by coating compact TiO 2 , methylam-monium lead halide (MAPbI), NiO-QDs and gold electrode (FTO/c-TiO 2 /MAPbI/NiO/Au). With the fabricated cell, we were able to obtain photo-conversion efficiency of 6.2%, fill factor of 0. 56, J sc is 10.77 mA/cm 2 and V oc is 1.02 V, which is a reasonable value for such cells.

Mechanochemical synthesis of melamine doped TiO2 nanoparticles for dye sensitized solar cells application

Journal of Materials Science: Materials in Electronics, 2018

In a quest for developing new material with performance of dye sensitized solar cells (DSSC) a no... more In a quest for developing new material with performance of dye sensitized solar cells (DSSC) a non-metallic doping i.e., of nitrogen was carried out to commercial TiO 2 nanoparticle using simple, facile and sustainable mechanochemistry method. Melamine was used as source of nitrogen and different weight percentages (10, 30, 50, 70 and 90%), mixed with TiO 2 mechanically in a ball mill for 12 h at an speed of 500 rotations per minute followed by annealing at 550 °C for 2 h under constant N 2 flow. The post nitrogen doping structural analysis indicated anatase phase of TiO 2 .The morphological observations by transmission electron microscopy did not show change due to melamine and particle size remains less than 30 nm. N-doping resulted in an increased wavelength of peak absorption from 334 nm to about 350 nm and shifting of absorption edge from UV (~ 400 nm) to visible region (~ 500 nm) resulting in the reduction of the band gap from 3.14 to 2.43 eV which is supported by XPS and Tauc plot analysis. The functional analysis reveals amide bond at higher melamine concentration. The DSSC characteristics were measured with source-meter coupled with simulated light source which shows a significant increase of cell efficiency from 26 with 10% of melamine to that of 86 with 90% melamine. The increase in efficiency was linear with increasing nitrogen doping concentration. The study suggested that melamine can be used as a suitable N-dopant source for improved photoconversion properties that can help engineer to develop a device with enhanced performance.

Communication-Ultra-Small NiO Nanoparticles Grown by Low- Temperature Process for Electrochemical Application

IOP Science, 2020

In this paper, we report a size-controlled metal oxide under a low-temperature process for the fa... more In this paper, we report a size-controlled metal oxide under a low-temperature process for the fabrication of an electrochemical sensor based on ultra-small nickel oxide (NiO) nanoparticles (NPs) which are utilized as electrode materials for the detection of n-butylamine chemical. The small size effect (~6 ± 0.5 nm) and richness of Ni3+ ion concentration of as-synthesized ultra-small NiO nanoparticles exhibited high and reproducible sensitivity of ~9.51mAcenterdotmM−1centerdotcm−2, limit of detection (LOD) ~144.21 μM and correlation coefficient (R) ~ 0.9688 with improved linearity in the range of 100 nM−100 μM.

format_quoteUltra-small NiO nanoparticles (6 ± 0.5 nm) exhibit a high sensitivity of ∼9.51 mA·mM⁻¹·cm⁻² for n-butylamine detection.format_quote

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Nickel Oxide Monodispersed Quantum Dots as Hole Transport Layer in n-i-p Hybrid Perovskite Solar Cells

American Scientific publisher, 2019

In this work NiO monodispersed quantum dots (QDs) were synthesized by the reduction of nickel (II... more In this work NiO monodispersed quantum dots (QDs) were synthesized by the reduction of nickel (II) acety-lacetonate with the borane-trimethylamine complex in a mixture of oleylamine, which acted as capping agent and helped to control the particle size growth. These were then used as a hole transport layer in regular (n-i-p) type organic-inorganic hybrid perovskite solar cells. Morphology of the NiO QDs was observed with Field emission electron microscope (FESEM) and high resolution transmission electron microscope (HR-TEM) that revealed a monodispersed particles of an average particle size of about 5.5 ± 0.5 nm with distinct lattice fringes (spacing of 0.24 nm). A solar cell was fabricated on FTO glass by coating compact TiO 2 , methylam-monium lead halide (MAPbI), NiO-QDs and gold electrode (FTO/c-TiO 2 /MAPbI/NiO/Au). With the fabricated cell, we were able to obtain photo-conversion efficiency of 6.2%, fill factor of 0. 56, J sc is 10.77 mA/cm 2 and V oc is 1.02 V, which is a reasonable value for such cells.

$Fig. 2. (a) X-ray diffraction spectrum of the synthesized NiO QDs; (b) FTIR spectrum of the synthesized NiO QDs; (c) FTIR spectrum of the synthesized MAPDI film; (d) UV-Visible spectrum of the synthesized NiO QDs. For the solar cell preparation, the FTO (1.5 cm x 2 cm) were degreased and cleaned using standard procedure. The synthesized composite was characterized for mor- phology by FESEM, (Hitachi S-4700, Japan) with EDX$

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Facile Synthesis of Highly Conductive Vanadium-Doped NiO Film for Transparent Conductive Oxide

MDPI Applied Sciences, 2020

Metal-oxide-based electrodes play a crucial role in various transparent conductive oxide (TCO) ap... more Metal-oxide-based electrodes play a crucial role in various transparent conductive oxide (TCO) applications. Among the p-type materials, nickel oxide is a promising electrically conductive material due to its good stability, large bandgap, and deep valence band. Here, we display pristine and 3 at.%V-doped NiO synthesized by the solvothermal decomposition method. The properties of both the pristine and 3 at.%V:NiO nanoparticles were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), Raman spectroscopy, ultraviolet-visible spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The film properties were characterized by atomic force microscopy (AFM) and a source meter. Our results suggest that incorporation of vanadium into the NiO lattice significantly improves both electrical conductivity and hole extraction. Also, 3 at.%V:NiO exhibits a lower crystalline size when compared to pristine nickel oxide, which maintains the reduction of surface roughness. These results indicate that vanadium is an excellent dopant for NiO.

format_quoteDoping NiO with 3 at.%V improved both film morphology and electrical conductivity compared to pristine NiO.format_quote

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Mechanochemical synthesis of melamine doped TiO2 nanoparticles for dye sensitized solar cells application

In a quest for developing new material with performance of dye sensitized solar cells (DSSC) a no... more In a quest for developing new material with performance of dye sensitized solar cells (DSSC) a non-metallic doping i.e., of nitrogen was carried out to commercial TiO 2 nanoparticle using simple, facile and sustainable mechanochemistry method. Melamine was used as source of nitrogen and different weight percentages (10, 30, 50, 70 and 90%), mixed with TiO 2 mechanically in a ball mill for 12 h at an speed of 500 rotations per minute followed by annealing at 550 °C for 2 h under constant N 2 flow. The post nitrogen doping structural analysis indicated anatase phase of TiO 2 .The morphological observations by transmission electron microscopy did not show change due to melamine and particle size remains less than 30 nm. N-doping resulted in an increased wavelength of peak absorption from 334 nm to about 350 nm and shifting of absorption edge from UV (~ 400 nm) to visible region (~ 500 nm) resulting in the reduction of the band gap from 3.14 to 2.43 eV which is supported by XPS and Tauc plot analysis. The functional analysis reveals amide bond at higher melamine concentration. The DSSC characteristics were measured with source-meter coupled with simulated light source which shows a significant increase of cell efficiency from 26 with 10% of melamine to that of 86 with 90% melamine. The increase in efficiency was linear with increasing nitrogen doping concentration. The study suggested that melamine can be used as a suitable N-dopant source for improved photoconversion properties that can help engineer to develop a device with enhanced performance.

$Fig. 1 X-ray diffraction spectra as a function of melamine content$

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