Abstract Although perovskite quantum dots (PQDs) have received considerable attention, defects in PQDs can significantly degrade the properties and device performance. In this study, we report on an effective strategy for synthesizing highly luminescent CH3NH3PbBr3 quantum dots (QDs) by a simple doping. To remove such defects, guanidinium bromide (GuBr) was doped into the CH3NH3PbBr3 QDs synthesized by the ligand-assisted reprecipitation technique. From XRD and TEM studies, the doping of GuBr into the QD lattices was verified. In addition, the surfaces of PQDs with and without GuBr dopants were analyzed by XPS to trace the metallic Pb acting as a major recombination center. The GuBr doping resulted in the size uniformity of QDs and effectively eliminated defects and metallic Pb, which enhanced the photoluminescence quantum yield (PLQY) through the inhibition of the non-radiative recombination pathway. Furthermore, the recombination dynamics in the QDs were examined by using time-resolved photoluminescence and fluorescence lifetime imaging to verify the role of GuBr dopants. By optimizing the amount of GuBr doping, the CH3NH3PbBr3 QDs with strong green emission achieved a maximum PLQY of 91.7%.

中文翻译：

---

具有 91.7% 光致发光量子产率的高度发光且稳定的 CH3NH3PbBr3 量子点：溴化胍掺杂剂的作用

摘要 尽管钙钛矿量子点（PQDs）受到了广泛关注，但 PQDs 中的缺陷会显着降低其性能和器件性能。在这项研究中，我们报告了一种通过简单掺杂合成高发光 CH3NH3PbBr3 量子点 (QD) 的有效策略。为了消除这些缺陷，将溴化胍 (GuBr) 掺杂到通过配体辅助再沉淀技术合成的 CH3NH3PbBr3 量子点中。从 XRD 和 TEM 研究中，证实了 GuBr 掺杂到 QD 晶格中。此外，通过 XPS 分析了含有和不含 GuBr 掺杂剂的 PQD 的表面，以追踪作为主要复合中心的金属 Pb。GuBr 掺杂导致 QD 的尺寸均匀，并有效地消除了缺陷和金属 Pb，通过抑制非辐射复合途径提高光致发光量子产率（PLQY）。此外，通过使用时间分辨光致发光和荧光寿命成像来检查 QD 中的复合动力学，以验证 GuBr 掺杂剂的作用。通过优化 GuBr 掺杂量，具有强绿色发射的 CH3NH3PbBr3 QD 实现了 91.7% 的最大 PLQY。