Avisek Dutta

Bio: Avisek Dutta is an academic researcher from Indian Association for the Cultivation of Science. The author has contributed to research in topics: Materials science & Doping. The author has an hindex of 6, co-authored 13 publications receiving 97 citations. Previous affiliations of Avisek Dutta include Indian National Association.

Design of a CdS/CdSe Heterostructure for Efficient H2 Generation and Photovoltaic Applications

Abstract: The design of nano-heterostructures for light-harvesting systems for photocatalysis and photovoltaic applications is an emerging area of research. Here, we report the synthesis of a one-dimensional quasi-type-II CdS/CdSe heterostructure where holes are confined in CdSe nanoparticles and electrons can delocalize throughout the conduction bands of both CdS nanorods and CdSe nanoparticles because of the smaller conduction band offset. By controlling the oxidation and reduction sites of the CdS/CdSe heterostructure, we achieved a maximum H2 generation of 5125 μmol/g/h for 27.5 wt % CdSe-loaded CdS heterostructure, which is found to be 44 times higher than that of bare CdS nanorods and 22 times higher than that of CdSe nanoparticles. Furthermore, this heterostructure exhibits a photovoltaic effect (Voc = 0.8 V, Jsc = 0.56 mA/cm2, FF = 40%, and η = 0.18), which could be useful for solar cell application. The bleaching recovery kinetics and hot electron cooling dynamics have been studied by using femtosecond tra...

Ultrafast Carrier Dynamics of Photo-Induced Cu-Doped CdSe Nanocrystals

Abstract: The understanding of ultrafast carrier relaxation process in doped semiconductor quantum dots (QDs) is very important for their potential applications in light-emitting diodes, optoelectronics. Here, we have studied the change in electronic properties of Cu-doped CdSe QDs upon light illumination. The light-induced effect leads to the enhancement of the band edge decay time and reduces the decay time of the dopant emission due to photocorrosion of Cu-doped CdSe QDs. The bleaching recovery kinetics and the hot electron cooling dynamics have been studied by using femtosecond transient absorption spectroscopy. It is observed that the electron cooling process of doped CdSe QDs is dependent on the dopant concentration and the cooling kinetics of doped CdSe QDs are found to be slower than undoped QDs. After light irradiation, the cooling processes of hot electron and recovery process in doped systems are modified.

Ultrafast Carrier Dynamics in 2D CdSe Nanoplatelets–CsPbX3 Composites: Influence of the Halide Composition

Abstract: Two-dimensional (2D) material-based composites are considered to be an important class of materials for light-harvesting applications because of their efficient charge separation. In this article, ...

Hybrid Nanostructures of 2D CdSe Nanoplatelets for High-Performance Photodetector Using Charge Transfer Process

Abstract: Two-dimensional (2D) semiconductor colloidal nanoplatelets (NPLs) have shown great potential as light-harvesting materials due to their advanced optical properties. Here, we have designed hybrid na...

Ultrafast carrier dynamics in 2D-2D hybrid structures of functionalized GO and CdSe nanoplatelets.

Abstract: Considerable attention has been paid to designing graphene based 2D hybrid nanostructures for their potential applications in various areas from healthcare to energy harvesting. Herein, we have prepared 2D–2D hybrid structures of 2D CdSe nanoplatelets (NPLs) with thiol (–SH) functionalized reduced graphene oxide (G-Ph-SH). Microscopic and spectroscopic studies reveal that the G-Ph-SH surface is successfully decorated by CdSe NPLs through a thiophenol (–SH) linker. The significant photoluminescence quenching (65%) and the shortening of decay time from 1 ns to 0.4 ns of CdSe NPLs are observed after adding 100 μg of G-Ph-SH. Furthermore, the femto-second transient absorption spectroscopic (fs-TAS) study reveals that the growth time of CdSe NPLs in the composite is reduced to 0.4 ps from 0.8 ps due to faster hot electron cooling. A faster component of 1.4 ps in the kinetic parameters of the composite system further suggests that the ultrafast electron transfer occurs from the conduction band of CdSe NPLs to surface functionalized reduced graphene oxide. This type of 2D–2D hybrid structure may open up new possibilities in light harvesting applications.

Principles Of Fluorescence Spectroscopy

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Semiconductor nanocrystals for small molecule activation via artificial photosynthesis

Abstract: Facile activation and conversion of small molecules (e.g., H2O, CO2, N2, CH4, and C6H6) into solar fuels or value-added chemicals under mild conditions is an attractive pathway in dealing with the worldwide appeal of energy consumption and the growing demand of industrial feedstocks. Compared with conventional thermo- or electro-catalytic approaches, the protocol of photocatalysis shines light on green and low-cost storage of sunlight in chemical bonds. For instance, artificial photosynthesis is an effective way to split H2O into molecular O2 and H2, thereby storing solar energy in the form of hydrogen fuel. Because of rational tunability in band gaps, charge-carrier dynamics, exposed active sites and catalytic redox activities by tailoring size, composition, morphology, surface, and/or interface property, semiconductor nanocrystals (NCs) emerge as very promising candidates for photo-induced small molecule activation, including H2O splitting, CO2 reduction, N2 fixation, CH4 conversion and chemical bond formation (e.g., S-S, C-C, C-N, C-P, C-O). In this review, we summarize the recent advances in small molecule activation via artificial photosynthesis using semiconductor NCs, especially those consisting of II-VI and III-V elements. Moreover, we highlight the intrinsic advantages of semiconductor NCs in this field and look into the fabrication of prototype devices for large-scale and sustainable small molecule activation to store solar energy in chemical bonds.

Accelerated photocatalytic degradation of iohexol over Co3O4/g-C3N4/Bi2O2CO3 of p-n/n-n dual heterojunction under simulated sunlight by persulfate

Abstract: A novel Co3O4/g-C3N4/Bi2O2CO3 (BCCN) photocatalyst with p-n/n-n heterojunction was synthesized through a solvent-thermal method. The degradation efficiency of 20 mg/L iohexol reached 94 % in 60 min (kapp =0.0417 min−1) in BCCN/light/PS system, which was 2.8 and 6.5 times higher than systems of BCCN/light (kapp =0.0150 min−1) and BCCN/PS (kapp =0.0064 min−1). The g-C3N4 addition lowered conduction band of the prepared material to produce superoxide radicals, activate persulfate and further prevent the recombination of photoelectrons and holes. Superoxide radicals and singlet oxygens were dominant radicals for iohexol degradation. Besides, persulfate could act as electron acceptor to enhance efficiency of electron transfer. The interaction between sulfate, superoxide and hydroxyl radicals improved singlet oxygens production. Furthermore, theoretical calculation and liquid chromatography mass spectrometry were performed to analyze degradation pathway of iohexol in the system. Ultimately, the BCCN/light/PS system can provide a new method to degrade organic pollutants in aquatic environments.

Two-dimensional semiconductor transition metal based chalcogenide based heterostructures for water splitting applications

Abstract: Recent research and development is focused in an intensive manner to increase the efficiency of solar energy conversion into electrical energy via photovoltaics and photo-electrochemical reactions. Electrocatalytic and photocatalytic water splitting into hydrogen and oxygen is a promising and emerging technology. Heterogeneous nanostructures based on semiconductor materials have attracted much attention to be used as catalysts, co-catalysts, photocatalysts and photoabsorbers. Development of transition metal dichalcogenide (TMDC) semiconductors with two dimensional (2D) layered structures and peculiar physical and chemical properties are playing a pivotal role in the heterogeneous photocatalytic hydrogen evolution (PHE) reaction. The energy band gap tuning with the thickness of the layers and heterojunction interface formation have given an opportunity to design and develop combinations of both photocatalysts and co-catalysts using semiconductor TMDCs. This contribution summarizes the recent investigations on the 2D semiconductor TMDC (MoS2, WS2, MoSe2 and WSe2) based heterogeneous nanostructures as efficient materials for photocatalytic water splitting applications to produce hydrogen. The literature survey clearly shows that more than 80% of the researchers in this field have worked on MoS2-based heterogeneous nanocomposites, as it is the 2nd most studied material after graphene. It is also evident that among the materials used so far for the PC HER activity, MoS2-based heterogeneous nanocomposites are on top with the highest hydrogen evolution rate and stability. Since the physical and chemical properties of the members are identical, the future research and development would focus on the manipulation of the rest of the TMDC members to achieve the future needs of clean and sustainable energy production.