Proceedings of International online conference on Hybrid materials and optoelectronic devices (HYBRIDOE)
DOI: https://doi.org/10.29363/nanoge.hybridoe.2020.050
Publication date: 4th December 2020
Low-temperature solution-processed halide perovskites light-emitting diodes (LEDs), which can present high brightness and efficient electroluminescence (EL) with good colour purity, show great application potential in lighting and displays. So far, high efficiency EL at very high brightness has been demonstrated in near-infrared and green perovskite LEDs. However, spectrally-stable blue perovskite LEDs with high brightness are difficult to achieve. Three-dimensional mixed-halide perovskites have potential to achieve high brightness EL, but their emission spectra are unstable as a result of halide phase separation. We reveal that there is already heterogeneous distribution of halides in the as-deposited perovskite films, which can trace back to the nonuniform mixture of halides in the precursors. By simply introducing cationic surfactants to improve the homogeneity of the halides in the precursor solution, we can overcome the phase segregation issue and obtain spectrally-stable single-phase blue-emitting perovskites. We demonstrate efficient blue perovskite LEDs with high brightness, e.g., luminous efficacy of 4.7, 2.9, 0.4 lm W-1 and luminance of over 37,000, 9,300, 1,300 cd m-2 for sky blue, blue and deep blue with Commission Internationale de l’Eclairage (CIE) coordinates of (0.068, 0.268), (0.091, 0.165), (0.129, 0.061) respectively, suggesting real promise of perovskites for LED applications.
Reference
Research, 2020, in press (Article ID 9017871)