MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Nanoscale. 2023 Mar 23;15(12):5696-5704. doi: 10.1039/d2nr07091j.
Anion-exchange reactions are recognized as a vital and facile post-synthesis method to precisely manipulate the emission spectra of perovskite quantum dots (QDs). However, the anion-exchange process often induces adverse structural evolution and trap-mediated mechanisms, so mixed-halide perovskite QDs suffer inefficient anion exchange and poor spectra-stability issues, which limits access to high-quality primary color perovskite QDs for display applications. Here we report an Al bonding-doping synergistic strategy for manufacturing stable mixed Br/Cl deep-blue perovskite QDs. By doping Al into perovskite QDs, highly-efficient Cl anion exchange and a large-range blue shift of the PL spectrum (∼62 nm with only 0.1 mmol of Cl feed) can be easily achieved. Notably, the Al-mediated deep-blue emission sample exhibits superior stability against moisture and electric fields. It also shows an elevated valence band maximum level. Based on the anion-exchanged QDs, a spectrum-stable deep-blue QLED with an EQE of 1.38% at 463 nm is achieved. Our findings demonstrate a feasible and promising strategy for developing high-performance deep-blue perovskite materials and optoelectronic devices.
阴离子交换反应被认为是一种重要且简便的后合成方法，可以精确地操纵钙钛矿量子点（QDs）的发射光谱。然而，阴离子交换过程通常会引起不利的结构演变和陷阱介导机制，因此混合卤化物钙钛矿 QDs 的阴离子交换效率低，光谱稳定性差，限制了高质量原色钙钛矿 QDs 在显示应用中的使用。在这里，我们报告了一种 Al 键合掺杂协同策略，用于制造稳定的混合 Br/Cl 深蓝光钙钛矿 QDs。通过将 Al 掺杂到钙钛矿 QDs 中，可以轻松实现高效的 Cl 阴离子交换和 PL 光谱的大范围蓝移（仅用 0.1mmol 的 Cl 进料就可以实现约 62nm 的蓝移）。值得注意的是，Al 介导的深蓝光发射样品在抵抗水分和电场方面表现出优异的稳定性。它还显示出更高的价带最大值水平。基于阴离子交换的 QDs，实现了光谱稳定的深蓝光 QLED，在 463nm 处的 EQE 为 1.38%。我们的研究结果表明，开发高性能深蓝光钙钛矿材料和光电器件的一种可行且有前景的策略。
