Size-confined lead-halide perovskite quantum dots (PQDs) are promising materials for optoelectronic devices. Large quantities of PQDs with high ensemble uniformity are often needed for device fabrication. The thermodynamic-equilibrium-controlled synthesis can produce PQDs with good size and shape uniformity. Unfortunately, scaling up this synthesis often produces unwanted perovskite nanoplatelets (NPLs). To date, the PQD and NPL growth mechanism under thermodynamic equilibrium control remains unexplored. We discovered that the growth of size-confined CsPbBr₃ PQDs is mediated by ultrasmall (∼2.4 nm) metastable nanoclusters. These nanoclusters can eventually grow into PQDs when sufficient Cs-precursors are provided. Otherwise, the unreacted nanoclusters will self-assemble and fuse into NPLs during the synthesis and/or PQD purification. By controlling the homogeneous growth of nanoclusters, strongly confined (≤5 nm) PQDs with high size uniformity can be produced at the gram scale.

中文翻译：

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揭示热力学平衡控制下强限域CsPbBr3钙钛矿量子点的生长机制

尺寸限制的卤化铅钙钛矿量子点（PQD）是用于光电器件的有前途的材料。器件制造通常需要大量具有高整体均匀性的 PQD。热力学平衡控制的合成可以生产具有良好尺寸和形状均匀性的PQD。不幸的是，扩大这种合成通常会产生不需要的钙钛矿纳米片（NPL）。迄今为止，热力学平衡控制下的 PQD 和 NPL 增长机制仍未被探索。我们发现尺寸限制的 CsPbBr ₃ PQD的生长是由超小（~2.4 nm）亚稳态纳米团簇介导的。当提供足够的 Cs 前体时，这些纳米团簇最终可以生长成 PQD。否则，未反应的纳米团簇将在合成和/或 PQD 纯化过程中自组装并融合成 NPL。通过控制纳米团簇的均匀生长，可以在克级生产具有高尺寸均匀性的强限制（≤5 nm）PQD。