High‐Performance CsPb_1−<i>x</i>Sn_<i>x</i>Br₃ Perovskite Quantum Dots for Light‐Emitting Diodes

Abstract

All inorganic CsPbBr₃ perovskite quantum dots (QDs) are potential emitters for electroluminescent displays. We have developed a facile hot-injection method to partially replace the toxic Pb²⁺ with highly stable Sn⁴⁺ . Meanwhile, the absolute photoluminescence quantum yield of CsPb_1-x Sn_x Br₃ increased from 45 % to 83 % with Sn^IV substitution. The transient absorption (TA) exciton dynamics in undoped CsPbBr₃ and CsPb_0.67 Sn_0.33 Br₃ QDs at various excitation fluences were determined by femtosecond transient absorption, time-resolved photoluminescence, and single-dot spectroscopy, providing clear evidence for the suppression of trion generation by Sn doping. These highly luminescent CsPb_0.67 Sn_0.33 Br₃ QDs emit at 517 nm. A device based on these QDs exhibited a luminance of 12 500 cd m^-2 , a current efficiency of 11.63 cd A^-1 , an external quantum efficiency of 4.13 %, a power efficiency of 6.76 lm w^-1 , and a low turn-on voltage of 3.6 V, which are the best values among reported tin-based perovskite quantum-dot LEDs.