Outcoupling Efficiency Enhanced Blue Perovskite Light-Emitting Diodes Constructed on the Mesoporous Surface of Nonplanar Rigid Molecular Scaffolds.

Producing nanostructures on a perovskite film through crystallization modulation is essential to improving the light outcoupling efficiency and performance of blue perovskite light-emitting diodes (PeLEDs). However, the challenge of achieving nanostructures on the blue perovskite films still remains. Herein, we demonstrate that the homogeneous nano holes are formed on the blue pure-bromide quasi-2D perovskite films because the crystallization kinetics of the blue perovskite are significantly modulated by the underneath mesoporous buffer layer of triptycene-like pyridine with biphenyl substituents (TPC-LB). This nonplanar rigid stereoscopic molecular structure of TPC-LB provides the ion channels in intermolecular and intramolecular cavities that effectively confine the components of perovskite. The formed nano holes on the perovskite films significantly enhance the outcoupling efficiency of the blue pure-bromide quasi-2D PeLEDs. The champion device shows a maximum luminance of 2004 cd m^-2 and a peak external quantum efficiency of 12.08%, which locates on the top rank of similar devices and is three times higher than that of the control device. This work demonstrates an effective strategy to improve the outcoupling efficiency of blue PeLEDs, which is of significance for promoting the development of PeLEDs.