Research

In this work, we address the possibility of obtaining three different microstructures on flexible metallic foil substrates followed by two surface treatments to engineer the morphology and charge transport kinetics. In short, we report (i) vertically aligned walls (ii) Valley-Hills and (iii) micro-granules on Cu/SS, Al and Ni substrates respectively. Further, the substrates induced CdTe microstructures were subjected to (i) gas-phase (Ar plasma) and wet-chemical (HNO₃) surface treatments to examine their roles on structural, optical and charge transport characteristics.

In this work, few layer nanoflakes of MoS₂ of different weight % are employed as an alternate efficient electron transport bridges in the bulk of TiO₂. It is observed that photo-injected electrons in the bulk TiO₂ prefers MoS₂ electron transport bridges to reach TCO as they are highly smooth, dangling bond-free and less resistive. The photovoltaic performance of the DSSCs was further examined by electro-chemical impedance spectroscopy and observed that electron lifetime in the bulk TiO₂ improved significantly by the incorporation of MoS₂.

In this work, we study influences of microwave treatment on structural characteristics of 2D-layered MoSe₂ films and the consequences on structural, optical and electrical charge transport behaviours. An important observation on co-existence of dual-phase MoO₃-MoSe₂ and its effect of light-matter interaction is elucidated. A detailed study on microwave assisted nano-morphological changes and their impacts on photo-current characteristics using (i) blue laser, (ii) green laser and (iii) AM 1.5 illuminations are presented to demonstrate the microwave energy interaction as a potential method to engineer the properties of 2D-layered MoSe₂.

In this work, a detailed structural, optical, nano-morphological evolution of heterogeneous WS₂-WO₃ films and their influences on photo-current measurements performed under three different illuminations were presented. Charge transport characteristics under dark and three different illuminations in the heterogeneous WS₂-WO₃ films were explained in terms of presence of oxy-sulfide heterogeneous phase WS₂-WO₃, two types of grain boundaries separating them and the associated defects with the boundaries. Finally, effect of argon plasma interaction with WS₂-WO₃ films and its consequences were explained.

Photovoltaic characteristics of dual oxy-sulfide phase WS₂-WO₃ samples were examined with respect to plasma treatment. It is concluded that photo-absorption in the visible spectral window can be increased using plasma treatment but achieving higher photo-current with respect to the duration of plasma treatment is rather challenging as the later depends more on injection, transport and collection of charge carriers that involve with different materials in a solar cell.

In this work, Photovoltaic performance enhancement via incorporation of chemical bath coated WS₂ quantum dots on TiO₂ is demonstrated. Studies revealed that it is possible to improve the performance due to the increased photo-absorption contributed by the WS₂ quantum dots. Further, it was also noticed that certain optimum quantity of WS₂ quantum dots facilitated charge transport in DSSCs while further increment in the WS₂ quantity impeded the performance. It is attributed to the possibility of formation of agglomeration in TiO₂ in which the charge transport was affected.