Perovskite-Inspired Materials for Outdoor and Indoor Photovoltaic Applications

Abstract

Clean and renewable energy sources are crucial for tackling the climate crisis and meeting the growing energy demand. Among the many emerging viable alternatives, solar energy stands out as an abundant and more sustainable energy source. Consequently, efficient, cost-effective, flexible, and low-toxic solar cells are needed. Lead halide perovskites (LHPs) represent a cutting-edge semiconductor technology known for their exceptional optoelectronic characteristics. LHPs have, hence, attracted increasing attention in solar cell application research. Nevertheless, toxicity concerns and stability issues associated with conventional LHPs limit their commercial applicability in photovoltaics. These concerns are particularly relevant in indoor environments, where there is a high risk of lead exposure to the end-user in case of a damage of consumer electronic devices containing lead. Additionally, LHPs possess intrinsic instability under moisture, illumination, and voltage bias.

This dissertation focuses on advancing and promoting research on lead-free perovskite-inspired materials (PIMs), particularly pnictogen-based metal halides for solar cells and indoor photovoltaics, to address the toxicity issues and instability concerns associated with perovskite-based photovoltaics. For the first time, we have employed Cu2AgBiI6 (CABI) PIM for indoor photovoltaics with an efficiency of 4.7% at 1000 lux white LED illumination. Additionally, we adopted several strategies to enhance film morphology and optical properties of CABI and Ag3BiI6 (ABI) PIMs and the performance of corresponding photovoltaics. Specifically, we (<i>i</i>) enhanced the photovoltaic performance of CABI via additive engineering by adding hydroiodic acid into the precursor, (<i>ii</i>) demonstrated the influence of the interfacial interaction between the CABI and hole transporting layer (HTL) on the shelf-life and operational stability, (<i>iii</i>) identified the correlation between shelf-life stability and operational stability, (<i>iv</i>) boosted the overall efficiency of CABI via cation engineering by antimony-bismuth alloying, (<i>v</i>) enhanced the charge transfer in ABI by a CsI thermally evaporated ultra-thin layer between the photoactive layer and HTL.

We hope that the findings of this dissertation will inspire other researchers in the field to delve deeper into exploring more PIMs, aiming to uncover their hidden potential as sustainable and air-stable alternatives to lead halide perovskites.