Bodnarchuk Maryna I, Feld Leon G, Zhu Chenglian, Boehme Simon C, Bertolotti Federica, Avaro Jonathan, Aebli Marcel, Mir Showkat Hassan, Masciocchi Norberto, Erni Rolf, Chakraborty Sudip, Guagliardi Antonietta, Rainò Gabriele, Kovalenko Maksym V
Laboratory for Thin Films and Photovoltaics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland.
Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich 8093, Switzerland.
ACS Nano. 2024 Feb 6;18(7):5684-97. doi: 10.1021/acsnano.3c11579.
The compositional engineering of lead-halide perovskite nanocrystals (NCs) via the A-site cation represents a lever to fine-tune their structural and electronic properties. However, the presently available chemical space remains minimal since, thus far, only three A-site cations have been reported to favor the formation of stable lead-halide perovskite NCs, i.e., Cs, formamidinium (FA), and methylammonium (MA). Inspired by recent reports on bulk single crystals with aziridinium (AZ) as the A-site cation, we present a facile colloidal synthesis of AZPbBr NCs with a narrow size distribution and size tunability down to 4 nm, producing quantum dots (QDs) in the regime of strong quantum confinement. NMR and Raman spectroscopies confirm the stabilization of the AZ cations in the locally distorted cubic structure. AZPbBr QDs exhibit bright photoluminescence with quantum efficiencies of up to 80%. Stabilized with cationic and zwitterionic capping ligands, single AZPbBr QDs exhibit stable single-photon emission, which is another essential attribute of QDs. In particular, didodecyldimethylammonium bromide and 2-octyldodecyl-phosphoethanolamine ligands afford AZPbBr QDs with high spectral stability at both room and cryogenic temperatures, reduced blinking with a characteristic ON fraction larger than 85%, and high single-photon purity (g(0) = 0.1), all comparable to the best-reported values for MAPbBr and FAPbBr QDs of the same size.
通过A位阳离子对卤化铅钙钛矿纳米晶体（NCs）进行组成工程是微调其结构和电子性质的一个手段。然而，目前可用的化学空间仍然很小，因为到目前为止，据报道只有三种A位阳离子有利于形成稳定的卤化铅钙钛矿NCs，即铯（Cs）、甲脒（FA）和甲基铵（MA）。受最近关于以氮丙啶鎓（AZ）作为A位阳离子的块状单晶的报道启发，我们展示了一种简便的胶体合成方法，可合成尺寸分布窄且尺寸可调至4 nm的AZPbBr NCs，在强量子限制区域产生量子点（QDs）。核磁共振（NMR）和拉曼光谱证实了AZ阳离子在局部扭曲的立方结构中的稳定性。AZPbBr量子点表现出明亮的光致发光，量子效率高达80%。用阳离子和两性离子封端配体稳定后，单个AZPbBr量子点表现出稳定的单光子发射，这是量子点的另一个重要属性。特别是，二甲基二癸基溴化铵和2-辛基十二烷基磷酸乙醇胺配体为AZPbBr量子点在室温和低温下提供了高光谱稳定性，减少了闪烁，特征开启分数大于85%，且单光子纯度高（g(0)=0.1），所有这些都与相同尺寸的MAPbBr和FAPbBr量子点的最佳报道值相当。
