Bright infra-red quantum dot light-emitting diodes through efficient suppressing of electrons

Colloidal quantum dots are promising materials for near infrared light emitting diodes (NIR QLEDs) owing to the widely tunable wavelength of emitted light, high quantum efficiency, and full integration with solution processing techniques. However, the imbalance of charge carriers in NIR QLEDs greatly limits their performance, which in turn narrows the scope of their application. Here, we propose an approach for improving the brightness and stability of NIR PbS QLEDs through balancing the device current by an ultra-thin inorganic aluminum oxide (Al2O3) electron suppressing layer. This modification resulted in a 7.42 W/sr/m2 peak radiance at 1.3 μm wavelength. Moreover, the halide-capped PbS-based NIR QLEDs remained stable under constant current drive for over 144 h.