Metal halide perovskite (MHP) semiconductors have garnered significant research attention due to their exceptional physical properties, including long charge carrier diffusion lengths and high absorption coefficients. Furthermore, their synthesis is relatively straightforward, requiring mild conditions and scalable methods that utilize non-critical metals. These characteristics position MHPs as promising, cost-efficient materials for a broad range of applications in photovoltaics, photocatalysis, optoelectronics, and beyond.

Our research group is focused on synthesizing metal halide perovskites from macroscopic structures to nanocrystals (NCs), employing a variety of chemical routes, including traditional wet chemistry and in-situ synthesis. This talk presents a novel strategy for the in-situ synthesis of perovskite NCs embedded in a nanocomposite, achieving outstanding optical properties and enhanced stability.

Hybrid materials of this nature have attracted increasing interest over the past decade as they mitigate NC aggregation and improve long-term stability. By embedding NCs into suitable matrices, it is possible to engineer multifunctional materials that combine optical, mechanical, electrical, thermal, electrochemical, or photocatalytic properties within a single system.

Over the past two years, we have developed an innovative in-situ synthesis method for various perovskite NCs with different compositions and dimensionalities. This approach involves the incorporation of MHPs into a metal- organic matrix (e.g., nickel acetate, magnesium acetate) to produce nanocomposite thin films via solution processing under ambient conditions, eliminating the need for an inert atmosphere (N₂ glovebox) [1,2,3,4].

We report the successful synthesis of 3D bulk lead-based perovskite NCs with different halides (Cl⁻, Br⁻, I⁻), incorporating both organic (MA⁺, FA⁺) and inorganic monovalent cations (Cs⁺). For specific compositions, we achieve near-unity photoluminescence quantum yield (PLQY). Furthermore, including bulky organic cations such as PEA⁺ and TEA⁺ enables the formation of low-dimensional tin-based perovskites with remarkable stability. In particular, the TEA-Sn molar ratio plays a crucial role in driving the formation and stabilization of 0D Sn-based MHPs, exhibiting exceptional photoluminescence and environmental resilience [5]. Additionally, we can also synthesize Ag- and Bi-based halide double perovskite NCs (i.e. Cs₂AgBiBr₆) with promising potential for catalytic applications. 

This method stands out for its exceptional reproducibility and process reliability under low-demanding fabrication conditions, making it an ideal platform for testing the synthesis of novel perovskites proposed through machine- learning approaches. Its key advantage lies in its high versatility and seamless compatibility with high-throughput roll-to-roll (R2R) printing techniques, enabling the scalable and cost-effective fabrication of large-area, high- performance devices. This approach has already shown a broad range of applications in photocatalysis [4], photovoltaics and light-emitting technologies such as lasing [6], down-conversion, and gas sensing.