Zhang Baowei, Liang Qi, Yong Xue, Wu Han, Chu Zhaoyang, Ma Yanhang, Brovelli Sergio, Manna Liberato, Lu Siyu
Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450000, China.
Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K.
Nano Lett. 2023 Oct 11;23(19):9050-9055. doi: 10.1021/acs.nanolett.3c02830. Epub 2023 Sep 27.
We report the colloidal synthesis of Bi-doped CsAgNaInCl double perovskite nanoplatelets (NPLs) exhibiting a near-unity photoluminescence quantum yield (PLQY), a record emission efficiency for nanoscale lead-free metal halides. A combination of optical spectroscopies revealed that nonradiative decay processes in the NPL were suppressed, indicating a well-passivated surface. By comparison, nanocubes with the same composition and surface ligands as the NPLs had a PLQY of only 40%. According to our calculations, the type of trap states arising from the presence of surface defects depends on their specific location: defects located on the facets of nanocubes generate only shallow traps, while those at the edges result in deep traps. In NPLs, due to their extended basal facets, most of the surface defects are facet defects. This so-called facet-defect tolerant behavior of double perovskites explains the more efficient optical emission of NPLs compared to that of nanocubes.
我们报道了Bi掺杂的CsAgNaInCl双钙钛矿纳米片（NPLs）的胶体合成，其光致发光量子产率（PLQY）接近1，这是纳米级无铅金属卤化物的创纪录发射效率。多种光谱学方法的结合表明，NPL中的非辐射衰减过程受到抑制，表明表面得到了良好的钝化。相比之下，与NPL具有相同组成和表面配体的纳米立方体的PLQY仅为40%。根据我们的计算，由表面缺陷产生的陷阱态类型取决于其特定位置：位于纳米立方体晶面上的缺陷仅产生浅陷阱，而位于边缘的缺陷则导致深陷阱。在NPL中，由于其扩展的基面，大多数表面缺陷是面缺陷。双钙钛矿的这种所谓的面缺陷耐受行为解释了NPLs比纳米立方体更有效的光发射。
