Otero-Martínez Clara, Zaffalon Matteo L, Ivanov Yurii P, Livakas Nikolaos, Goldoni Luca, Divitini Giorgio, Bora Sankalpa, Saleh Gabriele, Meinardi Francesco, Fratelli Andrea, Chakraborty Sudip, Polavarapu Lakshminarayana, Brovelli Sergio, Manna Liberato
CINBIO, Department of Physical Chemistry, Materials Chemistry and Physics Group, Universidade de Vigo, Campus Universitario As Lagoas-Marcosende, 36310 Vigo, Spain.
Nanochemistry, Istituto Italiano di Tecnología, Via Morego 30, 16163 Genova, Italy.
ACS Energy Lett. 2024 Apr 23;9(5):2367-2377. doi: 10.1021/acsenergylett.4c00693. eCollection 2024 May 10.
We report a colloidal synthesis of blue emissive, stable cube-shaped CsPbBr quantum dots (QDs) in the strong quantum confinement regime via dissolution-recrystallization starting from pre-syntesized (K Cs )PbBr nanocrystals which are then reacted with PbBr. This is markedly different from the known case of CsPbBr nanocrystals that react within seconds with PbBr and get transformed into much larger, green emitting CsPbBr nanocrystals. Here, instead, the conversion of (K Cs )PbBr nanocrystals to CsPbBr QDs occurs in a time span of hours, and tuning of the QD size is achieved by adjusting the concentration of the precursors. The QDs exhibit excitonic features in optical absorption that are tunable in the 420-452 nm range, accompanied by blue photoluminescence with quantum yield around 60%. Detailed spectroscopic investigations in both the single and multiexciton regime reveal the exciton fine structure and the effect of Auger recombination of these CsPbBr QDs, confirming theoretical predictions for this system.
我们报道了一种通过溶解-重结晶法在强量子限域区域内胶体合成蓝色发光、稳定的立方体形CsPbBr量子点（QDs）的方法，该方法从预合成的(K Cs )PbBr纳米晶体开始，然后与PbBr反应。这与已知的CsPbBr纳米晶体情况明显不同，后者在几秒钟内就与PbBr反应，并转变为大得多的、发出绿色光的CsPbBr纳米晶体。相反，在这里，(K Cs )PbBr纳米晶体向CsPbBr量子点的转化在数小时的时间跨度内发生，并且通过调节前驱体的浓度来实现量子点尺寸的调控。这些量子点在420-452nm范围内的光吸收中表现出可调节的激子特征，同时伴随着量子产率约为60%的蓝色光致发光。在单激子和多激子区域的详细光谱研究揭示了这些CsPbBr量子点的激子精细结构和俄歇复合效应，证实了该系统的理论预测。
