Conjugated Multifunctional Molecular Additives for Highly Efficient Perovskite Light-Emitting Diodes

Abstract

Perovskite light-emitting diodes (PeLEDs) have been developed for few years with great advances of the device performances. Despite of their excellent optical properties, perovskite emissive materials still need some adequate engineering to facilitate charge transport and improve the device efficiency. The crystal deformation occurred by residual stress, defect formation, and the subsequent non-radiative recombination are the major hurdles for efficient PeLEDs. Although molecular additives are widely used, the majorities of additives have insulating properties which have possibility of charge inhibition. Herein, we report highly efficient PeLEDs by introducing multifunctional conjugated molecular additives (Fl-OEGA and Fl-C8A) which effectively suppresses the interfacial defects, relaxes residual stress, and enhances charge transport. Finally, the conjugated additive of Fl-OEGA in perovskite film, resulting in high external quantum efficiency (EQE, 21.26%) of green based PeLED.