An Environmentally Stable and Lead-Free Chalcogenide Perovskite

TL;DR

This paper introduces BaZrS3, a lead-free chalcogenide perovskite, demonstrating its superior environmental stability over traditional lead-based perovskites and its potential in optoelectronic applications.

Contribution

The study presents BaZrS3 as a stable, lead-free perovskite with enhanced moisture and light resistance, supported by experimental and theoretical analysis.

Findings

BaZrS3 exhibits significantly slower degradation than MAPbI3 in moist environments.

Photodetectors based on BaZrS3 maintain ~60% responsivity after 4 weeks.

BaZrS3's stability is attributed to weak water interaction and low ion migration rates.

Abstract

Organic-inorganic halide perovskites are intrinsically unstable when exposed to moisture and/or light. Additionally, the presence of lead in many perovskites raises toxicity concerns. Herein is reported a thin film of BaZrS3, a lead-free chalcogenide perovskite. Photoluminescence and X-ray diffraction measurements show that BaZrS3 is far more stable than methylammonium lead iodide (MAPbI3) in moist environments. Moisture- and light-induced degradations in BaZrS3 and MAPbI3 are compared by using simulations and calculations based on density functional theory. The simulations reveal drastically slower degradation in BaZrS3 due to two factors - weak interaction with water, and very low rates of ion migration. BaZrS3 photo-detecting devices with photo-responsivity of ~46.5 mA W-1 are also reported. The devices retain ~60% of their initial photo-response after 4 weeks in ambient conditions. Similar MAPbI3 devices degrade rapidly and show ~95% decrease in photo-responsivity in just 4 days. The findings establish the superior stability of BaZrS3 and strengthen the case for its use in optoelectronics. New possibilities for thermoelectric energy conversion using these materials are also demonstrated.