Leng Meiying, Yang Ying, Chen Zhengwu, Gao Wanru, Zhang Jian, Niu Guangda, Li Dengbing, Song Haisheng, Zhang Jianbing, Jin Song, Tang Jiang
Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States.
Nano Lett. 2018 Sep 12;18(9):6076-6083. doi: 10.1021/acs.nanolett.8b03090. Epub 2018 Aug 20.
Metal halide perovskite quantum dots (QDs) recently have attracted great research attentions. However, blue-emitting perovskite QDs generally suffer from low photoluminescence quantum yield (PLQY) because of easily formed defects and insufficient surface passivation. Replacement of lead with low toxicity elements is also preferred toward potential commercial applications. Here, we apply Cl-passivation to boost the PLQY of MABiBr QDs to 54.1% at the wavelength of 422 nm, a new PLQY record for blue emissive, lead-free perovskite QDs. Because of the incompatible crystal structures between MABiBr and MABiCl and the careful kinetic control during the synthesis, Cl anions are engineered to mainly locate on the surface of QDs acting as passivating ligands, which effectively suppress surface defects and enhance the PLQY. Our results highlight the potential of MABiBr QDs for applications of phosphors, scintillators, and light-emitting diodes.
金属卤化物钙钛矿量子点（QDs）近来备受研究关注。然而，由于易形成缺陷以及表面钝化不足，发蓝光的钙钛矿量子点通常具有较低的光致发光量子产率（PLQY）。为了潜在的商业应用，用低毒性元素替代铅也是可取的。在此，我们采用氯钝化将MABiBr量子点在422nm波长处的PLQY提高到54.1%，这是蓝色发射、无铅钙钛矿量子点的新PLQY记录。由于MABiBr和MABiCl之间不相容的晶体结构以及合成过程中仔细的动力学控制，氯离子被设计主要定位在量子点表面作为钝化配体，这有效地抑制了表面缺陷并提高了PLQY。我们的结果突出了MABiBr量子点在磷光体、闪烁体和发光二极管应用中的潜力。
