@article { ISI:000270363600029, title = {Enhanced conversion efficiency in dye-sensitized solar cells based on hydrothermally synthesized TiO2-MWCNT nanocomposites}, journal = {ACS Applied Materials \& Interfaces}, volume = {1}, number = {9}, year = {2009}, month = {SEP}, pages = {2030-2035}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A 50 \% enhancement in the conversion efficiency (4.9-7.37 \%) is realized in dye-sensitized solar cells Using hydrothermally synthesized TiO2-multiwalled carbon nanotube (MWCNT) nanocomposites as compared to hydrothermally synthesized TiO2 without MWCNT and Degussa P25. Several characterizations have been employed to reveal the nature of the modification imparted to the MWCNTs under hydrothermal processing conditions and the resulting TiO2-MWCNT conjugation through -COOH groups. Efficient charge transfer In the nanocomposite and efficient electron transport by MWCNT (significantly higher Incident-photon-to-current conversion efficiency) are suggested to be the possible reasons for the enhancement.

}, keywords = {Carbon nanotubes, charge transfer, Dye-sensitized solar cells, Hybrid composite, hydrothermal}, issn = {1944-8244}, doi = {10.1021/am900396m}, author = {Muduli, Subas and Lee, Wonjoo and Dhas, Vivek V. and Mujawar, Sarfraj and Dubey, Megha and Vijayamohanan, K. and Han, Sung-Hwan and Ogale, Satishchandra} } @article { ISI:000269470200028, title = {Influence of dopant ions on properties of conducting polypyrrole and its electrocatalytic activity towards methanol oxidation}, journal = {Synthetic Metals}, volume = {159}, number = {15-16}, year = {2009}, month = {AUG}, pages = {1682-1688}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

The polypyrrole (PPy) films were deposited on vacuum metallized substrates by electro-oxidation of pyrrole monomer. These electrodes were then modified with a range of metal halides having different electronegativities. The modified polypyrrole electrodes were employed to investigate electrocatalytic activity towards methanol electrochemical oxidation by means of cyclic voltammetry in 0.1 M HClO(4) as supporting electrolyte. It was found that the electronegativity of the dopant ion incorporated in the PPy film governs the electrocatalytic activity towards methanol oxidation. Among different dopant anions used in the present work, the PPy doped with zirconium chloride gave the highest anodic current of 10 mA cm(-2) at the oxidation potential of methanol. Electrical property and the charge created due to doping in the polymers were measured using X-ray photoelectron spectroscopy (XPS) and Electron spin resonance spectroscopy (ESR). Electrocatalytic activity of the modified electrodes was correlated with various factors obtained from different polymer characterization experiments. The results were explained on the basis of the charge-transfer efficiency at the electrode I electrolyte interface, which was associated with the acceptor state created by the dopant in the semi-conducting polymer. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {charge transfer, electrocatalyst, ESR, Metal halide dopant, Methanol oxidation, polypyrrole, XPS}, issn = {0379-6779}, doi = {10.1016/j.synthmet.2009.05.007}, author = {Adhikari, Arindam and Radhakrishnan, S. and Patil, Rahul} } @article { ISI:000287058200011, title = {Dopant induced effect on electrocatalytic reduction of nitrobenzene using conducting polypyrrole thin film electrodes}, journal = {Journal of Applied Polymer Science}, volume = {120}, number = {2}, year = {2011}, month = {APR}, pages = {719-724}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

Conducting polypyrrole electrodes were prepared by electrochemical polymerization of pyrrole on vacuum-metallized glass substrates. These electrodes were modified by doping with a range of metal halides as dopant ions having different electronegativity. Electrochemical reduction of nitrobenzene using these electrodes was studied by means of cyclic voltammetry technique in acetonitrile medium containing aqueous HClO(4) (0.1M) as supporting electrolyte. It was found that the electronegativity of the dopant ion played a very important role in the electrocatalytic activity. Polypyrrole doped with nickel chloride gave the highest anodic current at the reduction potential of nitrobenzene. The results were explained on the basis of charge transfer efficiency at the electrode-electrolyte interface, which was associated with the acceptor state created by the dopant in the semi-conducting polymer. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 719-724, 2011

}, keywords = {charge transfer, conducting polymer, Doping, electrocatalysis, nitrobenzene, polypyrrole, reduction}, issn = {0021-8995}, doi = {10.1002/app.31417}, author = {Adhikari, Arindam and Radhakrishnan, S.} } @article { ISI:000345234900039, title = {Covalent organic framework-cadmium sulfide hybrid as a prototype photocatalyst for visible-light-driven hydrogen production}, journal = {Chemistry A-European Journal}, volume = {20}, number = {48}, year = {2014}, month = {NOV}, pages = {15961-15965}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

CdS nanoparticles were deposited on a highly stable, two-dimensional (2D) covalent organic framework (COF) matrix and the hybrid was tested for photocatalytic hydrogen production. The efficiency of CdS-COF hybrid was investigated by varying the COF content. On the introduction of just 1 wt\% of COF, a dramatic tenfold increase in the overall photocatalytic activity of the hybrid was observed. Among the various hybrids synthesized, that with 10 wt\% COF, named CdS-COF (90: 10), was found to exhibit a steep H2 production amounting to 3678 mmolh(-1) g(-1), which is significantly higher than that of bulk CdS particles (124 mmolh(-1)g(-1)). The presence of a p-conjugated backbone, high surface area, and occurrence of abundant 2D hetero-interface highlight the usage of COF as an effective support for stabilizing the generated photoelectrons, thereby resulting in an efficient and high photocatalytic activity.

}, keywords = {charge transfer, covalent organic frameworks, hybrid materials, hydrogen production, Photocatalysis}, issn = {0947-6539}, doi = {10.1002/chem.201403800}, author = {Thote, Jayshri and Aiyappa, Harshitha Barike and Deshpande, Aparna and Diaz, David Diaz and Kurungot, Sreekumar and Banerjee, Rahul} } @article {43956, title = {Facile synthesis of β-functionalized {\textquotedblleft}push-pull{\textquotedblright} Zn(II) porphyrins for DSSC applications}, journal = {Dyes and Pigments}, volume = {147}, year = {2017}, month = {DEC}, pages = {56-66}, type = {Journal Article}, abstract = {

Three new β-substituted {\textquotedblleft}push-pull{\textquotedblright} Zn(II) porphyrin dyes with various electron donors at meso-positions and cyanoacetic acid as acceptor at β-position have been designed and synthesized. These porphyrins have been characterized by UV-Vis, Fluorescence, 1H NMR and 13C NMR spectroscopic techniques and cyclic voltammetric studies. The Soret and Q band of Zn(II) porphyrin dyes were found to be red-shifted (30{\textendash}35 nm) as compared to ZnTPP. The fluorescence quenching and the decrement in quantum yield and lifetime suggest intramolecular charge transfer from donor to acceptor. Zn porphyrins exhibited anodic shift in their first redox potentials (0.03{\textendash}0.11 V) as compared to ZnTPP. The HOMO-LUMO energy levels of Zn porphyrin dyes were compared with the conduction band of TiO2 and the electrolyte I-/I3 -. The HOMO levels of all the dyes are sufficiently higher than the energy level of electrolyte I-/I3 - and LUMO levels significantly lower than the conduction band of TiO2 which reflect the feasibility of facile electron-transfer. ZnT(Mes)P(CN-COOH) has been co-sensitized with N719 dye to further improve the PCE efficiency. These dyes displayed power conversion efficiency (PCE) of η = 1.72{\textendash}3.13\% where co-sensitized ZnT(Mes)P(CN-COOH) (N719) dye demonstrated maximum PCE efficiency up to 5.35\%, with a Jsc of 11.8 mA cm-2, a Voc of 630 mV and a fill factor (FF) of 72\% due to better light harvesting capacity.

}, keywords = {charge transfer, Conduction Bands, Cyanoacetic Acid, Electrolytes, Floorescence, Redox Reaction, zinc compounds}, doi = {10.1016/j.dyepig.2017.07.053}, author = {Prakash, K.}, editor = {Manchanda, S.} } @article {43923, title = {G - C3N4 (2D)/CdS (1D)/rGO (2D) dual-interface nano-composite for excellent and stable visible light photocatalytic hydrogen generation}, journal = {International Journal of Hydrogen Energy}, volume = {42}, year = {2017}, month = {MAR}, pages = {5971-5984}, type = {Journal }, abstract = {

A 2D/1D/2D dual-interface nano-composite configuration in the form of CdS nanorods sandwiched between g-C3N4 and rGO sheets with intimate interfacial contact is synthesized by a facile wet-chemical method and is shown to exhibit excellent photocatalytic H2 generation under visible-light irradiation. In particular, the optimal g-C3N4/CdS/rGO dual-interface nano-composite shows H2 production rate of \~{}4800 μmol h-1 g-1, which is almost 44, 11 and 2.5 times higher than that shown by pure g-C3N4 nanosheets, and the g-C3N4/rGO and g-C3N4/CdS single interface heterostructures, respectively. It is shown that the synergic effects involving the band structure match and close interfacial contact, which can accelerate the separation and transfer of photoinduced charge carriers, and the enhanced visible-light absorption together contribute to the impressive photocatalytic performance and photostability of the g-C3N4/CdS/rGO ternary nano-composite system. Specific advantages of a dual-interface triple-composite system over a single interface case(s) are also brought out.

}, keywords = {charge transfer, Dual Interface, G - CN, H Generation, Hetero Structure, Nano - Composite}, doi = {10.1016/j.ijhydene.2016.11.065}, author = {Tonda, Surendar}, editor = {Kumar, Santosh} } @article {44194, title = {Marginally hydrogenated triphasic titania nanotubes for effective visible-light photocatalytic hydrogen generation}, journal = {Energy Technology}, volume = {6}, year = {2018}, month = {FEB}, pages = {280-288}, type = {Article}, abstract = {

We report the first demonstration of hydrogen-annealed triphase TiO nanotubes (anatase-rutile-brookite) (T-ARB) as a visible-light-active photocatalyst for water splitting with high quantum efficiency. As-synthesized T-ARB was annealed under hydrogen atmosphere at 250 and 4508 degrees C for 2 h. We found that the tubular structures were retained in the hydrogenated TiO2 samples. It was observed that the concentrations of Ti3+ and the oxygen vacancies and their distribution significantly increased with respect to the hydrogen annealing temperature. Such changes in defects were found to be critical in enhancing the photocatalytic activity of the hydrogen-annealed triphase TiO2 nanotubes. The triphase TiO2 nanotubes hydrogen annealed at 450 degrees C were 16 times more efficient than pristine TiO2. Such an increase in the photocatalytic activity was explained by a triphase band diagram with defect states below the conduction band of each phase, which facilitated visible-light activity and easy transfer of charge carriers from one phase to another. Our study showed that the well-designed multiphase construction with oxygen vacancies enhanced the photocatalytic activity tremendously owing to the presence of a higher number of phase junctions.

}, keywords = {charge transfer, Defects, Hydrogenation, titania, water splitting}, issn = {2194-4288}, doi = {10.1002/ente.201700406}, author = {Preethi, Laguduva K. and Mathews, Tom and Walczak, Lukasz and Gopinath, Chinnakonda S.} } @article {47729, title = {Structure-tailored non-noble metal-based ternary chalcogenide nanocrystals for pt-like electrocatalytic hydrogen production}, journal = {ChemSusChem}, volume = {14}, year = {2021}, month = {AUG }, pages = {3074-3083}, type = {Article}, abstract = {A facile microwave-assisted strategy was employed to synthesize Ni3Bi2S2 nanocrystals. Variation in the synthesis conditions tuned the composition of monoclinic and orthorhombic phases of Ni3Bi2S2. The electrochemical hydrogen evolution activity of the catalyst with highest percentage of monoclinic phase demonstrated a negligible onset potential of only 24 mV close to that of state-of-the-art Pt/C with an overpotential as low as 88 mV. Density functional theory calculations predicted the monoclinic phase exhibit the lowest adsorption free energy corresponding to hydrogen adsorption (Delta GadsH*) and, therefore, the highest hydrogen evolution activity amongst the considered phases. The quasi-2D structure of monoclinic phase facilitated an increased charge-transfer between Ni and Bi, favoring the downward shift of the d-band center to enhance the catalytic activity.}, keywords = {charge transfer, electrocatalysis, hydrogen evolution reaction, Nanomaterials, ternary chalcogenides}, issn = {1864-5631}, doi = {10.1002/cssc.202100967}, author = {Sarkar, Shreya and Rawat, Abhishek and Das, Tisita and Gaboardi, Mattia and Chakraborty, Sudip and Vinod, C. P. and Peter, Sebastian C.} } @article {48818, title = {Chemical bridge-mediated heterojunction electron transport layers enable efficient and stable perovskite solar cells}, journal = {ACS Applied Materials and Interfaces}, volume = {15}, year = {2023}, month = {JUN}, pages = {29597-29608}, type = {Article}, abstract = {

Perovskite solar cells (PSCs) emerged as potential photovoltaicenergy-generating devices developing in recent years because of theirexcellent photovoltaic properties and ease of processing. However,PSCs are still reporting efficiencies much lower than their theoreticallimits owing to various losses caused by the charge transport layerand the perovskite. In this regard, herein, an interface engineeringstrategy using functional molecules and chemical bridges was appliedto reduce the loss of the heterojunction electron transport layer.As a functional interface layer, ethylenediaminetetraacetic acid (EDTA)was introduced between PCBM and the ZnO layer, and as a result, EDTAsimultaneously formed chemical bonds with PCBM and ZnO to serve asa chemical bridge connecting the two. DFT and chemical analyses revealedthat EDTA can act as a chemical bridge between PCBM and ZnO, passivatedefect sites, and improve charge transfer. Optoelectrical analysisproved that EDTA chemical bridge-mediated charge transfer (CBM-CT)provides more efficient interfacial charge transport by reducing trap-assistedrecombination losses at ETL interfaces, thereby improving device performance.The PSC with EDTA chemical bridge-mediated heterojunction ETL exhibiteda high PCE of 21.21\%, almost no hysteresis, and excellent stabilityto both air and light.

}, keywords = {charge transfer, chemical bridge, electron transport layer, ethylenediaminetetraacetic acid, Perovskite solar cells, trap-assisted recombination}, issn = {1944-8244}, doi = {10.1021/acsami.3c04852}, author = {Patil, Pramila and Maibam, Ashakiran and Sangale, Sushil S. and Mann, Dilpreet Singh and Lee, Hyun-Jung and Krishnamurty, Sailaja and Kwon, Sung-Nam and Na, Seok-In} } @article {49219, title = {Photocatalytic regeneration of reactive cofactors with inP quantum dots for the continuous chemical synthesis}, journal = {ACS Catalysis}, volume = {14}, year = {2024}, month = {APR}, pages = {6740-6748}, type = {Article}, abstract = {

The shuttling of redox-active nicotinamide cofactors between the light and dark cycles is the key to the continuous production of biomass in photosynthesis. The replication of such processes in artificial photosynthetic systems demands fast photoregeneration as well as simultaneous integration of these nicotinamide cofactors into the dark cycle. Here, we report the design of an artificial photosynthetic system for the continuous production of butanol via the constant photoregeneration and consumption of nicotinamide cofactors, powered by an indium phosphide quantum dot (InP QD) photocatalyst and alcohol dehydrogenase (ADH) enzyme, respectively. A strong electrostatic attraction between the oppositely charged InP QDs and electron mediators significantly enhanced the charge extraction and utilization processes, enabling a fast (similar to 30 min, with a turn over frequency of similar to 1333 h(-1)), quantitative (\>99\%), and selective photoregeneration of enzymatically active nicotinamide cofactors in the light cycle. These photoregenerated nicotinamide cofactors were further coupled in the dark cycle to trigger the ADH oxidoreductase enzyme for the production of butanol, via sequential as well as simultaneous light-dark cycles. The amount of butanol produced under simultaneous light-dark cycles was higher than the stoichiometric limit, proving the constant regeneration and consumption of nicotinamide cofactors in light and dark cycles, respectively. Thus, a proper design and integration of the InP QD-based photocatalytic cycle with the enzymatic cycle led to the effective electron shuttling between light and dark cycles, as seen in photosynthesis.

}, keywords = {artificial photosynthesis, biologicalcofactors, charge transfer, indiumphosphide, Photocatalysis, quantum dots}, issn = {2155-5435}, doi = {10.1021/acscatal.4c00817}, author = {Chakraborty, Indra Narayan and Jain, Vanshika and Roy, Pradyut and Kumar, Pawan and Vinod, Chathakudath P. and Pillai, Pramod P.} } @article {49540, title = {Charge transfer effect on relaxation mechanism in hydrated pyrrole-water systems following N-2s ionization}, journal = {ChemPhysChem}, volume = {26}, year = {2025}, month = {APR}, type = {Article}, abstract = {

This study investigates the relaxation mechanisms of pyrrole and pyrrole-water clusters (C4H5N-(H2O)n, where n=0-3 \${n = 0 - 3}\$ ) following N-2s ionization of pyrrole. Using various theoretical methods, we focus on the influence of water molecules and charge transfer on these non-radiative relaxation pathways. Our simulations included pyrrole solvated in 494 explicit water molecules equilibrated at 300 K and also employed a polarizable continuum model (PCM) to make the system more realistic and gain additional insights. In hydrated environments, the hydrogen bonding network between pyrrole and surrounding water molecules facilitates enhanced non-radiative relaxation pathways following inner valence ionization. Since these are hydrogen bonding systems, we have explored the possibility of proton transfer, which could occur in conjunction with other electronic decay processes.

}, keywords = {ab initio-calculations, auger decay, charge transfer, proton transfer, pyrrole}, issn = {1439-4235}, doi = {10.1002/cphc.202400962}, author = {Kumar, Ravi and Bhattacharjee, Kankana and Ghosh, Aryya and Vaval, Nayana} }