Tin‐Based Chiral Perovskites with Second‐Order Nonlinear Optical Properties

Abstract

Metal halide perovskites have attracted extensive attention as the most favorable candidate for nonlinear optical (NLO) effects, due to their superior infrared transparency, flexible structures, and high laser‐induced damage thresholds. Among the perovskite branches, the lead‐based perovskites dominate in virtue of their fascinating optoelectronic properties. However, the ambient instability and toxicity of lead impede their practical applications. Herein, a new class of air‐stable and lead‐free zero‐dimension chiral perovskites manifesting efficient second‐order NLO response is reported. Interestingly, the tin‐based perovskites demonstrate double‐step reversible phase transitions with an acentric space group P21 at room temperature, whereas their racemic counterparts undergo a distinct one‐step phase transition crystallizing in centric space group P21/c. These findings reveal an executable approach to designing multifunctional lead‐free perovskite‐type switchable materials with second harmonic generation (SHG) properties.

Keywords

• chiral perovskites
• lead-free
• nonlinear optical properties
• phase transitions
• second harmonic generation