Enhanced Light-Outcoupling and Defect Suppression of FAPbBr<sub>3</sub> Nanocrystals via Conjugated Ligands for Efficient Light-Emitting Diodes
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초록
내용
Perovskite nanocrystals (PNCs) exhibit superior optoelectronic properties, which make them promising semiconductors for achieving highly-efficient light-emitting diodes (LEDs). The external quantum efficiencies (EQEs) of perovskite LEDs (PeLEDs) have rapidly increased to over 20% within few years. Despite the impressive progress of PeLEDs, there is limited research detailing their intrinsic light outcoupling. Herein, the use of short-chain ligand, 4-fluoro-phenethylammonium bromide (FPEABr), is proposed to fine-tune the refractive index (n) and horizontal dipole ratio values (ΘH) of the perovskite emission layer. The FAPbBr3 NC films exhibit a lower n value than that of bulk perovskite films and an enhanced ΘH. As a result, the FPEABr-FAPbBr3 based device achieved an enhanced EQE of 11.34% compared with the pristine PeLEDs (EQE of 6.45%). In conclusion, this work offers inspiration for enhancing intrinsic light outcoupling efficiency of PeLEDs.