Solari Simon F, Kumar Sudhir, Jagielski Jakub, Kubo Nikolas M, Krumeich Frank, Shih Chih-Jen
Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1 CH-8093 Zürich Switzerland
Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir Prelog Weg 1 CH-8093 Zürich Switzerland.
J Mater Chem C Mater. 2021 Mar 25;9(17):5771-5778. doi: 10.1039/d0tc04667a.
Colloidal nanocrystals (NCs) of lead halide perovskites have generated considerable interest in the fabrication of optoelectronic devices, such as light emitting-diodes (LEDs), because of their tunable optical bandgap, narrow spectral width, and high defect tolerance. However, the inhomogeneous halide distribution within individual NCs remains a critical challenge in order to obtain color-stable electroluminescence in mixed-halide systems. Here, we demonstrate a new post-synthetic approach, ligand-assisted solid phase synthesis (LASPS), for the preparation of electroluminescent colloidal NCs of methylammonium (MA) lead halide perovskites, at room temperature. The slow reaction kinetics preserves the morphology, size, and shape in the resulting NCs whose emission covers the entire visible spectral region with photoluminescence (PL) quantum yields (QYs) of up to >90% and colloidal stability up to several months. The LEDs fabricated using the prepared mixed-halide NCs display narrowband electroluminescence (EL) ranging from 476 to 720 nm. The optimized red LEDs exhibit an external quantum efficiency, , of up to 2.65%, with the CIE 1931 color coordinates of (0.705, 0.290), nearly identical to those of the red primary in the recommendation (rec.) 2020 standard (0.708, 0.292).
卤化铅钙钛矿胶体纳米晶体（NCs）因其可调谐的光学带隙、窄光谱宽度和高缺陷容忍度，在发光二极管（LED）等光电器件制造中引起了广泛关注。然而，为了在混合卤化物体系中获得颜色稳定的电致发光，单个NCs内卤化物分布不均匀仍然是一个关键挑战。在此，我们展示了一种新的合成后方法，即配体辅助固相合成（LASPS），用于在室温下制备甲基铵（MA）卤化铅钙钛矿的电致发光胶体NCs。缓慢的反应动力学保留了所得NCs的形态、尺寸和形状，其发射覆盖整个可见光谱区域，光致发光（PL）量子产率（QYs）高达>90%，胶体稳定性长达数月。使用制备的混合卤化物NCs制造的LED显示出476至720 nm的窄带电致发光（EL）。优化后的红色LED的外量子效率高达2.65%，CIE 1931色坐标为（0.705, 0.290），与推荐（rec.）2020标准中的红色原色（0.708, 0.292）几乎相同。
