Shape-preserving transformation of carbonate minerals into lead halide perovskite semiconductors based on ion exchange/insertion reactions.

Biological and bio-inspired mineralization processes yield a variety of three-dimensional structures with relevance for fields such as photonics, electronics and photovoltaics. However, these processes are only compatible with specific material compositions, often carbonate salts, thereby hampering widespread applications. Here we present a strategy to convert a wide range of metal carbonate structures into lead halide perovskite semiconductors with tunable bandgaps, while preserving the 3D shape. First, we introduce lead ions by cation exchange. Second, we use carbonate as a leaving group, facilitating anion exchange with halide, which is followed rapidly by methylammonium insertion to form the perovskite. As proof of principle, pre-programmed carbonate salt shapes such as vases, coral-like forms and helices are transformed into perovskites while preserving the morphology and crystallinity of the initial micro-architectures. This approach also readily converts calcium carbonate biominerals into semiconductors, furnishing biological and programmable synthetic shapes with the performance of artificial compositions such as perovskite-based semiconductors.