Lead halide perovskite (LHP) nanocrystals (NCs) have recently garnered enhanced development efforts from research disciplines owing to their superior optical and optoelectronic properties. These materials, however, are unlike conventional quantum dots, because they possess strong ionic character, labile ligand coverage, and overall stability issues. As a result, the system as a whole is highly dynamic and can be affected by slight changes of particle surface environment. Specifically, the surface ligand shell of LHP NCs has proven to play imperative roles throughout the lifetime of a LHP NC. Recent advances in engineering and understanding the roles of surface ligand shells from initial synthesis, through postsynthetic processing and device integration, finally to application performances of colloidal LHP NCs are covered here.
In recent years, there have been rapid advances in the synthesis of lead halide perovskite nanocrystals (NCs) for use in solar cells, light emitting diodes, lasers, and photodetectors. These compounds have a set of intriguing optical, excitonic, and charge transport properties, including outstanding photoluminescence quantum yield (PLQY) and tunable optical band gap. However, the necessary inclusion of lead, a toxic element, raises a critical concern for future commercial development. To address the toxicity issue, intense recent research effort has been devoted to developing lead‐free halide perovskite (LFHP) NCs. In this Review, we present a comprehensive overview of currently explored LFHP NCs with an emphasis on their crystal structures, synthesis, optical properties, and environmental stabilities (e.g., UV, heat, and moisture resistance). In addition, strategies for enhancing optical properties and stabilities of LFHP NCs as well as the state‐of‐the‐art applications are discussed. With the perspective of their properties and current challenges, we provide an outlook for future directions in this rapidly evolving field to achieve high‐quality LFHP NCs for a broader range of fundamental research and practical applications.
more » « less- NSF-PAR ID:
- 10127290
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 59
- Issue:
- 3
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 1030-1046
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract -
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The development of halide perovskite (HP) based thin film solar cells has been unprecedented in the past few years, and there is significant ongoing effort aiming to make perovskite solar cells (PSCs) more efficient and stable. Parallel to the PSC research, there is growing interest in exploring the synthesis and physiochemical behaviors of HP nanocrystals (NCs). While these HP NCs inherently possess many unique properties that are suitable for the use in PSCs, the reported effort of incorporating HP NCs into PSCs is still highly limited. As a result, there is a gap between HP NC and PSC research. In this context, we provide here a brief review of the established HP NC synthesis and a discussion of the several recent studies pertaining to the use of HP NCs in PSCs. Based on these, we provide perspectives on promising directions for bridging the gap between HP NC and PSC research in the future.more » « less
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Abstract Despite the groundbreaking advancements in the synthesis of inorganic lead halide perovskite (LHP) nanocrystals (NCs), stimulated from their intriguing size‐, composition‐, and morphology‐dependent optical and optoelectronic properties, their formation mechanism through the hot‐injection (HI) synthetic route is not well‐understood. In this work, for the first time, in‐flow HI synthesis of cesium lead iodide (CsPbI3) NCs is introduced and a comprehensive understanding of the interdependent competing reaction parameters controlling the NC morphology (nanocube vs nanoplatelet) and properties is provided. Utilizing the developed flow synthesis strategy, a change in the CsPbI3NC formation mechanism at temperatures higher than 150 °C, resulting in different CsPbI3morphologies is revealed. Through comparison of the flow‐ versus flask‐based synthesis, deficiencies of batch reactors in reproducible and scalable synthesis of CsPbI3NCs with fast formation kinetics are demonstrated. The developed modular flow chemistry route provides a new frontier for high‐temperature studies of solution‐processed LHP NCs and enables their consistent and reliable continuous nanomanufacturing for next‐generation energy technologies.
