Rapid and Reversible Switching of Photoluminescence through Structural Dimensionality in Lead-Free Sb-Doped (CH3NH3)2NaInBr6 Double Perovskite

Abstract Stimuli-responsive photoluminescent halide double perovskites present environmentally benign alternatives to lead-based systems for sensing and information encryption. Here, we report acetone-induced rapid transformation of a yellow-emissive (λem = 585 nm), one-dimensional (CH3NH3)2NaInBr6:Sb double perovskite to an orange-emissive (λem = 660 nm), zero-dimensional (CH3NH3)4InBr7:Sb compound. This structural and optical switching occurs within seconds and is reversible over multiple cycles. This study presents a rare example of solvatochromism in a hybrid In(III)-based halide double perovskite, significantly expanding the scope of this important class of materials for optical switching applications.