Perovskite quantum-dot-based light-emitting diodes (QLEDs) are highly promising for future solid-state lightings and high-definition displays due to their excellent color purity. However, their device performance is easily affected by charge accumulation induced luminescence quenching due to imbalanced charge injection in the devices. Here we report green perovskite QLEDs with simultaneously improved efficiency and operational lifetime through balancing the charge injection with the employment of a bilayered electron transport structure. The charge-balanced QLEDs exhibit a color-saturated green emission with a full-width at half-maximum (FWHM) of 18 nm and a peak at 520 nm, a low turn-on voltage of 2.0 V and a champion external quantum efficiency (EQE) of 21.63%, representing one of the most efficient perovskite QLEDs so far. In addition, the devices with modulated charge balance demonstrate a nearly 20-fold improvement in the operational lifetime compared to the control device. Our results demonstrate the great potential of further improving the device performance of perovskite QLEDs toward practical applications in lightings and displays via rational device engineering.

基于钙钛矿量子点的发光二极管 (QLED) 由于其出色的色纯度，在未来的固态照明和高清显示器中非常有前途。然而，由于器件中的电荷注入不平衡，它们的器件性能很容易受到电荷积累引起的发光猝灭的影响。在这里，我们报告了绿色钙钛矿 QLED，通过平衡电荷注入和双层电子传输结构的使用，同时提高了效率和使用寿命。电荷平衡的 QLED 表现出颜色饱和的绿色发射，半峰全宽 (FWHM) 为 18 nm，峰值为 520 nm，低开启电压为 2.0 V，外部量子效率最高 ( EQE）为 21.63%，是迄今为止最高效的钙钛矿 QLED 之一。此外，与控制设备相比，具有调制电荷平衡的设备的使用寿命提高了近 20 倍。我们的研究结果表明，通过合理的设备工程，进一步提高钙钛矿 QLED 的设备性能在照明和显示器的实际应用中具有巨大潜力。