Sellotape Exfoliated Layered Quasi-2D Perovskite Thin Film for Efficient Light-Emitting Diodes

摘要

In 2004, K. S. Novoselov and A. K. Geim et al. have used sellotape topeel off the layered 2D graphite, and successfully obtained few-layerthin graphene. Inspired by this, herein, the sellotape is initially usedto exfoliate the layered Ruddlesden–Popper (RP) quasi-2D perovskitefilm for efficient light-emitting diodes application. The top surface layerof quasi-2D perovskite film is mechanically peeled off by the sellotapewithout damaging the crystalline region below, which minimizes the poorconductivity issue of quasi-2D perovskite film owing to the decreaseddefect density. Moreover, the exfoliated quasi-2D film exhibits low chargetraps density and enhanced energy transfer from low-dimensional to highdimensionaldomains due to the elimination of surface defective layerand the recrystallization of quasi-2D perovskite crystal, leading to highphotoluminescencequantum yield (PLQY) up to 83.2. Subsequently, anefficient perovskite light-emitting diode based on the exfoliated quasi-2Dperovskite thin film is achieved with high current efficiency of 46.0 cd m~(?2)and excellent external quantum efficiency (EQE) up to 14.8.