Lead-Free Perovskite Nanosystems for Photocatalytic Applications

Bhattacharjee, Subhajit (2019) Lead-Free Perovskite Nanosystems for Photocatalytic Applications. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Subhajit Bhattacharjee (14MS167)) 14MS167.pdf - Submitted Version Restricted to Repository staff only Download (4MB)

Abstract

Lead-free halide perovskites have emerged as a new class of promising semiconductor materials, which are relatively less toxic and more robust as compared to their lead-based counterparts. The exciting optical properties of these perovskites lead to the facile generation of excitons upon light exposure, depending on the nature of their band-gap. Herein, for the first time, we have exploited the photo-absorption property of the lead-free perovskites to catalyse the degradation of water pollutant methylene blue (MB) in presence of visible light. We first carried out the photocatalytic experiments in isopropanol medium as a proof-of-concept since the perovskites lose their molecular integrity when added to water. In an unprecedented approach we have employed the perovskites for dye degradation in water medium by designing composite systems, which facilitated charge extraction and decelerated the penetration of water into the perovskite layer. We obtained excellent MB degradation efficiencies with a very small amount of catalyst loading as compared to the best reported photocatalysts employed for MB degradation. The best performing photocatalyst system provides ~90% MB degradation at room temperature within one hour. In addition, we have also tested the lead-free perovskites for photovoltaic applications. The fabricated photovoltaic (PV) device shows good diode characteristics in absence of light.

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