Ding Yang, Zhang Zhuoming, Toso Stefano, Gushchina Irina, Trepalin Vadim, Shi Kejia, Peng Jeffrey W, Kuno Masaru
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Nanochemistry Department, Instituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
J Am Chem Soc. 2023 Mar 22;145(11):6362-6370. doi: 10.1021/jacs.2c13527. Epub 2023 Mar 7.
Key features of syntheses, involving the quaternary ammonium passivation of CsPbBr nanocrystals (NCs), include stable, reproducible, and large (often near-unity) emission quantum yields (QYs). The archetypical example involves didodecyl dimethyl ammonium (DDDMA)-passivated CsPbBr NCs where robust QYs stem from interactions between DDDMA and NC surfaces. Despite widespread adoption of this synthesis, specific ligand-NC surface interactions responsible for large DDDMA-passivated NC QYs have not been fully established. Multidimensional nuclear magnetic resonance experiments now reveal a new DDDMA-NC surface interaction, beyond established "tightly bound" DDDMA interactions, which strongly affects observed emission QYs. Depending upon the existence of this new DDDMA coordination, NC QYs vary broadly between 60 and 85%. More importantly, these measurements reveal surface passivation through unexpected didodecyl ammonium (DDA) that works in concert with DDDMA to produce near-unity (i.e., >90%) QYs.
涉及CsPbBr纳米晶体（NCs）季铵钝化的合成的关键特性包括稳定、可重现且高（通常接近1）的发射量子产率（QYs）。典型例子是双十二烷基二甲基铵（DDDMA）钝化的CsPbBr NCs，其强大的QYs源于DDDMA与NC表面之间的相互作用。尽管这种合成方法被广泛采用，但导致DDDMA钝化的NCs具有高QYs的特定配体-NC表面相互作用尚未完全明确。多维核磁共振实验现在揭示了一种新的DDDMA-NC表面相互作用，这超出了已确定的“紧密结合”的DDDMA相互作用，它强烈影响观察到的发射QYs。根据这种新的DDDMA配位的存在情况，NC的QYs在60%至85%之间有很大差异。更重要的是，这些测量揭示了通过意想不到的十二烷基铵（DDA）进行的表面钝化，它与DDDMA协同作用以产生接近1（即>90%）的QYs。
