Inhibiting phase separation of perovskite quantum dots for achieving stable blue light-emitting diodes

Perovskite quantum dots light-emitting diodes (PQLEDs), due to the advantages of high luminous efficiency, high color purity, adjustable spectral range, etc., has an excellent prospect in the next generation of high-definition displays. As an indispensable part of displays, blue PQLEDs are usually achieved by mixing halogen, which, however, will lead to halogen ion migration and phase separation of perovskite material at high temperature and bias pressure, thus make the electroluminescent spectrum redshift. In this manuscript, we propose a strategy to inhibit phase separation of blue perovskite quantum dots (PQDs) by introducing alkali metal , and obtain stable perovskite quantum dot light-emitting diodes. The PQLEDs based on this strategy show an external quantum efficiency (EQE) of 1.87% and a brightness of 3757 cd m −2 , and can still guarantee stable electroluminescence (EL) spectra at a bias of up to 14 V. The work is beneficial for probing into the mechanism of suppressing the phase separation of mixed halogen blue PQDs and offer a promising strategy to enhance the color stability of blue PQLEDs.