Bi Chenghao, Wang Shixun, Li Qiang, Kershaw Stephen V, Tian Jianjun, Rogach Andrey L
Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China.
Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP) , City University of Hong Kong , Kowloon , Hong Kong SAR.
J Phys Chem Lett. 2019 Mar 7;10(5):943-952. doi: 10.1021/acs.jpclett.9b00290. Epub 2019 Feb 18.
All-inorganic perovskite quantum dots (QDs) have emerged as potentially promising materials for lighting and displays, but their poor thermal stability restricts their practical application. In addition, optical characteristics of the blue-emitting CsPbX QDs lag behind their red- and green-emitting counterparts. Herein, we addressed these two issues by doping divalent Cu ions into the perovskite lattice to form CsPbCu X QDs. Extended X-ray absorption fine structure (EXAFS) measurements reveal that doping smaller Cu guest ions induces a lattice contraction and eliminates halide vacancies, which leads to an increased lattice formation energy and improved short-range order of the doped perovskite QDs. This results in the improvement of both the thermal stability and the optical performance of CsPbCu (Br/Cl) QDs, which exhibit bright blue photoluminescence at 450-460 nm, with a high quantum yield of over 80%. The CsPbCu X QD films maintain stable luminescence performance even when annealed at temperatures of over 250 °C.
全无机钙钛矿量子点（QDs）已成为用于照明和显示的潜在有前景的材料，但其较差的热稳定性限制了它们的实际应用。此外，发射蓝光的CsPbX量子点的光学特性落后于发射红光和绿光的量子点。在此，我们通过将二价铜离子掺杂到钙钛矿晶格中以形成CsPbCuX量子点来解决这两个问题。扩展X射线吸收精细结构（EXAFS）测量表明，掺杂较小的铜客体离子会引起晶格收缩并消除卤化物空位，这导致掺杂钙钛矿量子点的晶格形成能增加和短程有序性改善。这导致CsPbCu（Br/Cl）量子点的热稳定性和光学性能均得到改善，其在450-460nm处表现出明亮的蓝色光致发光，量子产率超过80%。即使在超过250°C的温度下退火，CsPbCuX量子点薄膜仍保持稳定的发光性能。
