Colloidal lead halide perovskite nanocrystals (PNCs), as a new generation of semiconductor materials, exhibit a range of exceptional optoelectronic properties and outstanding performance across various applications. However, the ionic nature of perovskite materials results in an extremely rapid reaction rate, with most reported synthesis methods requiring the reaction to be terminated within tens of seconds. This poses a significant challenge for the synthesis of high-quality nanocrystals. Despite extensive research, only a limited number of studies have managed to extend the reaction time for fully inorganic CsPbBr₃ nanocrystals. Compared to fully inorganic perovskites, organic-inorganic hybrid perovskites offer richer functionalities and are the dominant materials for high-performance solar cells, light-emitting diodes, and other optoelectronic applications. Nevertheless, the stronger ionic nature of organic-inorganic hybrid perovskites makes their synthesis even more challenging, and effective methods for producing high-quality hybrid PNCs remain scarce.
To address these challenges, Professors Wanli Ma and Zeke Liu from the Institute of Functional Nano & Soft Materials (FUNSOM) at Soochow University have recently developed a novel diffusion-controlled synthesis strategy that significantly decelerates the reaction rate of organic-inorganic hybrid PNCs. The core innovation involves using lead thiocyanate (Pb(SCN)₂) as a new precursor. The limited solubility of this precursor in the reaction system enables the continuous and gradual supply of monomers, thereby preventing the rapid monomer consumption that typically causes premature Ostwald ripening. This ensures a sustained size-focused growth mode over an extended reaction window. Leveraging this strategy, the reaction time for organic-inorganic hybrid PNCs has been remarkably extended from the typical tens of seconds to over 180 minutes. This synthesis strategy is applicable to all organic-inorganic hybrid perovskite nanocrystal materials, yielding PNCs with highly uniform sizes, near-100% photoluminescence quantum yield (PLQY), and scalability for batch production. Moreover, the prolonged reaction time opens new opportunities for designing and fabricating innovative perovskite nanocrystal structures, such as core-shell structures, heterojunctions, and doped materials. The findings have been published in Nature Synthesis (DOI: 10.1038/s44160-024-00678-3). The first author, Sun Xiang, is a 2024 master's graduate from the institute and is continuing his doctoral studies at FUNSOM.
In a commentary published in the same issue of Nature Synthesis (DOI: 10.1038/s44160-024-00691-6), renowned optoelectronics expert and academician, Professor Tae-Woo Lee from Seoul National University highly praised this work.
The study also benefited from significant contributions by Professor Boyuan Shen's team and Professor Yaxing Wang's team from Soochow University, as well as Professor Qing Shen's team from the University of Electro-Communications in Japan, who provided critical support in morphology characterization and exciton dynamics analysis. This research was supported by the National Key Research and the National Natural Science Foundation of China and other funding sources.
Fig. 1 Growth mechanisms for hybrid lead halide PNCs.
Fig. 2 Monitoring the growth of FAPbI3 nanocrystals synthesized by conventional and diffusion-mediated approaches.
Link to paper：https://www.nature.com/articles/s44160-024-00678-3
Title：Diffusion-mediated synthesis of high-quality organic-inorganic hybrid perovskite nanocrystals
Authors：Xiang Sun, Lin Yuan, Yang Liu, Guozheng Shi, Yumin Wang, Chunmeng Liu, Xuliang Zhang, Yaxin Zhao, Chenyu Zhao, Mengmeng Ma, Boyuan Shen, Yaxing Wang, Qing Shen, Zeke Liu* & Wanli Ma*
Link to News & Views：https://www.nature.com/articles/s44160-024-00691-6
Editor: Danting Xiang, Xin Du