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

Abstract

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.

Broadband highly directive 3D nanophotonic lenses

“…Finally, the methodology described herein is quite general—a combination of flexible 3D design with a virtually universally compatible fabrication technique, to create complex structures. Although laser lithography was used for our proof-of-concept demonstration, there has been great progress in making complex 3D dielectric shapes through scalable self-assembly processes 48 , which even allow for conversion to light-emitting 3D structures 49 . These methods may thus also be possible to employ for the design and creation of structures for applications in spectroscopy, microscopy, photocatalysis, or any number of other processes where nanoscale control of light is demanded.…”

Flow‐Induced Precipitation in Thin Capillaries Creates Helices, Lamellae, and Tubes

“…Moreover, we suggest that these precipitate structures can be further stabilized by addition of silicate to allow fast flow through unconventional catalysts beds with high surface areas. In this context, it will be important to investigate post‐synthetic modifications such as the thermal conversion of Zn(OH) 2 to ZnO and the use of other metal ions . Lastly, future work should aim to develop a better understanding of the complex role of surface tension, densities, kinetics, diffusion, and particle aggregation in these systems.…”

“…In this context,i tw ill be important to investigate post-synthetic modifications such as the thermalc onversion of Zn(OH) 2 to ZnO [16] and the use of other metal ions. [17] Lastly,f uture work should aim to develop ab etter understanding of the complex role of surface tension,d ensities, kinetics, diffusion, andp article aggregation in these systems.…”

Homogeneous Freestanding Luminescent Perovskite Organogel with Superior Water Stability

“…Recently many strategies have been explored for stabilizing the perovskite materials exposed to various harsh environments. For instance, surface modification including shape‐preserving transformation, oligomeric ligand functionalization, and silica matrix encapsulation have been reported to improve the stability, but PNPs in those demonstrations are not fully water resistant. Dense waterproof polymers, such as polystyrene, were used to encapsulate and protect PNPs against moisture.…”

“…Previous works focusing on the enhancement of stability of PNPs either encapsulate PNPs at the surface of polymer thin film through spin coating fabrication, or wrap premade NPs within polymer beads forming luminescent powders . These complex fabrication procedures and the lack of substrates options in these methods severely limit the PNP composites to 2D structures or even lower dimensions.…”