(C₆H₅CH₂NH₃)₂CuBr₄: A Lead-Free, Highly Stable Two-Dimensional Perovskite for Solar Cell Applications

The toxicity and the instability of lead-based perovskites might eventually hamper the commercialization of perovskite solar cells. Here, we present the optoelectronic properties and stability of a two-dimensional layered (C₆H₅CH₂­NH₃)₂CuBr₄ perovskite. This material has a low <i>E</i>_g of 1.81 eV and high absorption coefficient of ∼1 × 10⁵ cm^–1 at the most intensive absorption at 539 nm, implying that it is suitable for light-harvesting in thin film solar cells, especially in tandem solar cells. Furthermore, X-ray diffraction (XRD), ultraviolet–visible (UV–vis) absorption spectra, and thermogravimetric analysis (TGA) confirm the high stability toward humidity, heat, and ultraviolet light. Initial studies produce a mesoscopic solar cell with a power conversion efficiency of 0.2%. Our work may offer some useful inspiration for the further investigation of environment-friendly and stable organic–inorganic perovskite photovoltaic materials

Organic–Inorganic Copper(II)-Based Material: A Low-Toxic, Highly Stable Light Absorber for Photovoltaic Application

Lead halide perovskite solar cells have recently emerged as a very promising photovoltaic technology due to their excellent power conversion efficiencies; however, the toxicity of lead and the poor stability of perovskite materials remain two main challenges that need to be addressed. Here, for the first time, we report a lead-free, highly stable C₆H₄NH₂CuBr₂I compound. The C₆H₄NH₂CuBr₂I films exhibit extraordinary hydrophobic behavior with a contact angle of ∼90°, and their X-ray diffraction patterns remain unchanged even after 4 h of water immersion. UV/vis absorption spectrum shows that C₆H₄NH₂CuBr₂I compound has an excellent optical absorption over the entire visible spectrum. We applied this copper-based light absorber in printable mesoscopic solar cell for the initial trial and achieved a power conversion efficiency of ∼0.5%. Our study represents an alternative pathway to develop low-toxic and highly stable organic–inorganic hybrid materials for photovoltaic application