Co-Interlayer Engineering for Homogenous Phase Quasi-2-D Perovskite and High-Performance Deep-Blue Light-Emitting Diodes

Organic and inorganic hybrid perovskites are a class of solution-processable semiconductors that hold significant promise for light-emitting diode applications. However, the development of efficient blue perovskite light-emitting diodes (PeLEDs) has remained a critical challenge. Although significant advancements have been achieved in the development of sky-blue PeLEDs, the performance of pure-blue and deep-blue PeLEDs still lags. In this manuscript, by incorporating 1-cyclohexene-1-ethanamine cation (CEA+) into the host 1-phenylbutylamine cation (PBA+) spacer and fabricating mixed-cations quasi-2D perovskites, a homogeneous phase distribution in quasi-2D perovskite films is achieved through precise tuning of the phase formation energy. The resulting PeLEDs exhibit remarkable performance with an external quantum efficiency (EQE) of 5.8% at 467 nm, which is one of the highest EQEs among the deep-blue light quasi-2D PeLED devices with emission wavelengths below 470 nm, Additionally, the device demonstrates a half-lifetime of approximate to 25 min. Furthermore, the PeLEDs utilizing mixed-cation perovskite exhibit a stable electroluminescence (EL) spectrum under varying voltage biases, even when the chlorine content in the halogen sites reaches as high as 30%. Overall, this work offers a novel and promising avenue to achieve both high EQE and a stable EL spectrum in blue-light quasi-2D PeLEDs. By incorporating 1-cyclohexene-1-ethanamine cation into the host 1-phenylbutylamine cation spacer and fabricating mixed-cations quasi-2D perovskites, a homogeneous phase distribution in quasi-2D perovskite films is achieved through precise tuning of the phase formation energy. The resulting PeLEDs exhibit remarkable performance with an external quantum efficiency (EQE) of 5.8% at 467 nm. image