Water and oxygen stability has been one of the major bottlenecks in practical application of perovskite quantum dots (PeQDs). Recently, ultra-thin alumina via atomic layer deposition (ALD) has been used as protective coating to improve the stability of PeQDs. However, the use of organo-metallic trimethylaluminum (TMA) precursor is typically accompanied by undesirable photoluminescence quenching of PeQDs. We investigate in detail the interaction mechanism between TMA and amine ligands-capped PeQDs to shed light on the origin of such quenching. First-principles calculations reveal that TMA is highly reactive to insert into amine ligands and PeQDs, which disrupts the bonding between ligand and the PeQDs surface. The demethylation of the insertion product would induce substantial trap states on the PeQDs surface, resulting in the degradation of photoluminescence. Methyl aluminum diisopropoxide (MADI) with asymmetric structure is proposed as an ALD precursor for the treatment of PeQDs. Due to the tight binding of the isopropyl groups to the Al atom, MADI can effectively avoid successive dissociation after reaction with surface ligands, avoiding the formation of trap states. This work highlights the importance of precursor engineering for ligand passivation and provides guidance to the design of precursors with minimal trap-states for highly efficient and stable PeQDs.

水和氧的稳定性一直是钙钛矿量子点（PeQDs）实际应用的主要瓶颈之一。最近，通过原子层沉积（ALD）的超薄氧化铝已被用作保护涂层，以提高 PeQD 的稳定性。然而，使用有机金属三甲基铝 (TMA) 前体通常伴随着不希望的 PeQD 的光致发光猝灭。我们详细研究了 TMA 和胺配体封端的 PeQD 之间的相互作用机制，以阐明这种猝灭的起源。第一性原理计算表明，TMA 对插入胺配体和 PeQDs 具有高反应性，这会破坏配体与 PeQDs 表面之间的键合。插入产物的去甲基化会在 PeQDs 表面诱导大量陷阱状态，导致光致发光的退化。具有不对称结构的甲基二异丙醇铝 (MADI) 被提议作为 ALD 前体用于处理 PeQD。由于异丙基与Al原子的紧密结合，MADI可以有效避免与表面配体反应后连续解离，避免形成陷阱态。这项工作突出了前体工程对配体钝化的重要性，并为设计具有最小陷阱态的前体以实现高效和稳定的 PeQD 提供了指导。避免形成陷阱状态。这项工作突出了前体工程对配体钝化的重要性，并为设计具有最小陷阱态的前体以实现高效和稳定的 PeQD 提供了指导。避免形成陷阱状态。这项工作突出了前体工程对配体钝化的重要性，并为设计具有最小陷阱态的前体以实现高效和稳定的 PeQD 提供了指导。