Perovskite light-emitting diodes (PeLEDs) provide excellent opportunities for low-cost, color-saturated, and large-area displays. However, the performance of blue PeLEDs lags far behind that of their green and red counterparts. Here, we show that the external quantum efficiencies (EQEs) of blue PeLEDs scale linearly with the photoluminescence quantum yields (PL QYs) of CsPb(Br x Cl 1− x ) 3 nanocrystals emitting at 460 to 480 nm. The recombination efficiency of carriers is highly sensitive to the chlorine content and the related deep-level defects in nanocrystals, causing notable EQE drops even with minor increases in chlorine defects. Minor adjustments of chlorine content through rubidium compensation on the A-site effectively suppress the formation of nonradiative defects, improving PL QYs while retaining desirable bandgaps for blue-emitting nanocrystals. Our PeLEDs with record-high efficiencies span the blue spectrum, achieving peak EQEs of 12.0% (460 nm), 16.7% (465 nm), 21.3% (470 nm), 24.3% (475 nm), and 26.4% (480 nm). This work exemplifies chlorine-defect control as a key design principle for high-efficiency blue PeLEDs.

中文翻译：

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基于减少氯缺陷的混合卤化物钙钛矿的高效蓝色发光二极管


钙钛矿发光二极管 (PeLED) 为低成本、色彩饱和和大面积显示器提供了绝佳的机会。然而，蓝色 PeLED 的性能远远落后于绿色和红色同类产品。在这里，我们发现蓝色 PeLED 的外量子效率 (EQE) 与 CsPb(Br) 的光致发光量子产率 (PL QY) 呈线性关系。 x氯1− x ） 3发射波长为 460 至 480 nm 的纳米晶体。载流子的复合效率对纳米晶体中的氯含量和相关的深能级缺陷高度敏感，即使氯缺陷略有增加，也会导致EQE显着下降。通过 A 位上的铷补偿对氯含量进行微调，可有效抑制非辐射缺陷的形成，提高 PL QY，同时保留发蓝光纳米晶体所需的带隙。我们的 PeLED 具有创纪录的高效率，跨越蓝色光谱，峰值 EQE 分别为 12.0% (460 nm)、16.7% (465 nm)、21.3% (470 nm)、24.3% (475 nm) 和 26.4% (480 nm) ）。这项工作例证了氯缺陷控制作为高效蓝色 PeLED 的关键设计原则。