All-inorganic CsPbX₃ (X = Cl, Br, I) quantum dots (QDs) are promising materials for light-emitting diodes (LEDs), but the long insulating ligands such as oleic acid (OA) and oleylamine (OLA) on the QD surface limit the device performances. They reduce the electrical conductivity of QDs, while their loss deteriorates the photoluminescence and stability. To overcome these issues, octylphosphonic acid (OPA) with a shorter carbon chain was added in the synthesis of perovskite QDs to partially replace OA ligands. Owing to the strong interaction between OPA and Pb atoms, the under­coordinated Pb atoms on the surface of CsPbI₃ QDs can be effectively passivated by OPA, leading to improved fluorescence quantum efficiency (close to unity) and solution stability. Furthermore, the electrical conductivity of QD films was also enhanced from 5.3×10^-4 to 1.1×10^-3 S/m by using shorter chain OPA ligands. Finally, highly efficient red perovskite QD LEDs with peak external quantum efficiency (EQE) of 12.6% and maximum luminance of 10171 cd m^-2 were achieved in a top-emitting device structure, a nearly 3-fold enhancement in luminance compared with pristine CsPbI₃ QDs based LEDs.

全无机CsPbX ₃（X = Cl，Br，I）量子点（QDs）是发光二极管（LED）的有前途的材料，但是长的绝缘配体（例如油酸（OA）和油胺（OLA）） QD表面会限制设备性能。它们降低了量子点的电导率，而它们的损耗则使光致发光和稳定性下降。为了克服这些问题，在钙钛矿QD的合成中添加了具有较短碳链的辛基膦酸（OPA），以部分替代OA配体。由于OPA和Pb原子之间的强相互作用，CsPbI ₃表面上未配位的Pb原子量子点可以被OPA有效钝化，从而提高荧光量子效率（接近于1）和溶液稳定性。此外，通过使用较短链的OPA配体，QD膜的电导率也从5.3×10 ^-4提高到1.1×10 ^-3 S / m。最终，在顶部发光器件结构中获得了峰值外部量子效率（EQE）为12.6％和最大亮度为10171 cd m ^-2的高效红色钙钛矿QD LED，与原始CsPbI相比，亮度提高了近3倍_3个基于QD的LED。