Dimensional semiconducting materials such as Transition metal dichalcogenides (TMDs), 2D perovskites, vacancy ordered perovskites (VOP) have gained attention because of their remarkable optoelectronic properties and extraordinary stability. 2D perovskites have a layered structure with octahedral layers separated by a large spacer cation. An interesting aspect of these layered perovskite structures is their layer dependent optical properties where the increase in octahedral layers decreases the bandgap of the material. These extraordinary properties have laid path to explore these 2D perovskites in photovoltaic and LED applications. The TMDs also have a layered type structure which has a direct bandgap nature at monolayer and they also have a complementary absorption of infrared (IR) portion along with visible portion in the solar spectrum. Utilizing these properties, these materials find a huge application in photovoltaics. A material or a class of materials that can remain stable in aqueous media along with good absorption properties would be ideal for next generation PEC devices. Recently the vacancy ordered double perovskites based on A2B+4X6 have been reported to show high stability in harsh pH conditions coupled with good absorption properties.
In this work, Thin-film solar cells with Rhenium sulfide and bromo-propylammonium lead bromide (BrPA2PbBr4) layered perovskite for photovoltaic applications, and vacancy ordered perovskites based on Cs2ReX6 (X - Cl, Br) for stable solar water oxidation materials as photo absorbers were successfully synthesized. In case of rhenium sulfide (ReS2), thin film ReS2 was successfully synthesized using chemical vapour deposition (CVD) method and the synthesized material has been tested as a photo absorber for solar cell application. At least ten different device configurations with various charge transport layers and back contacts have been investigated among which an appropriate devices configuration that could generate photocurrent has been figured out. The charge transport properties were investigated, and the recombination dynamics were identified in these ReS2 devices. In case of VOPs, we report two rhenium compounds in the family of vacancy ordered perovskites, Cs2ReX6 (X – Cl, Br) that remain extremely stable in ambient and harsh pH conditions. These two materials Cs2ReCl6 (CReC) and Cs2ReBr6 (CReB), were synthesized using hydrothermal method and their structural, thermal, optical, and electrochemical properties were explored. Their ability to act as photoanodes and perform solar water oxidation was investigated in detail. In case of layered perovskite, single crystals of bromo-propylammonium lead bromide (BrPA2PbBr4) were synthesized and their structural properties such as crystal structure, Raman spectroscopy, and optical properties such as absorbance, photo luminescence, and lifetime were studied. Finally, their solar cell application and electro chemical impedance spectroscopy (EIS) were conducted to infer upon their charge transfer kinetics. A fundamental study on influence of electric bias on the 2D BrPA2PbBr4 were also performed to understand their effect on structural and optical properties. These experimental findings will provide further directions to explore these materials for energy generation applications.