Facile synthesis of durable perovskite quantum dots film with near unity photoluminescence quantum yield for efficient perovskite light emitting diode

摘要

In this work, a bright uniform PSK QDs film is synthesized in-situ using an amorphous polymer and optimizing the stoichiometry. The in-situ formed QDs film grown in the presence of poly(vinylpyrrolidone) chains shows a photoluminescence quantum yield (PLQY) as high as 98% even under low light intensities (0.01 mW/cm(2)) with a long shelf lifetime of up to 2 years under ambient light (nanocrystals retain 100% of the initial PLQY). The near unity PLQY is due to the passivation of the surface defects of the PSK QDs by the Lewis base pyrrolidone groups of the polymer chain. Further, the QDs film shows higher thermal stability that increases by a factor of more than 5 compared to the bulk film. High efficient green perovskite light emitting diodes (PLEDs) are fabricated without electron transporting layer using the high luminescent in situ synthesized low roughness QDs film with a current efficiency of 48.18 cd/A and power efficiency of 6.88 lm/W. Such devices start emitting green light at 2.5 V and reach a maximum luminance of 124727 cd m(-2) at 7 V with external quantum efficiency of 10.5%. Further, the flexible PLED based on PSK QDs yields a maximum luminance of 43990 cd m(-2) at 7 V.