Efficient Radiative Enhancement in Perovskite Light‐Emitting Devices through Involving a Novel Sandwich Localized Surface Plasmon Structure

Abstract In recent years, CsPbX₃ (X = Cl, Br, I) perovskite quantum dots (QDs) have been considered as the most promising materials for light‐emitting diodes (LEDs). However, the advances of CsPbX₃ quantum dot‐based light emitting diodes (QLEDs) still lagged behind inorganic III–V LEDs and other organic LEDs. Herein, a strategy to improve the performances of perovskite QLEDs is reported by utilizing the localized surface plasmon resonance (LSPR) effects of Au nanospheres (NSs). It is accomplished by introducing a Au NS layer into the electron transport layer of Ca²⁺‐CsPbBr₃ QLEDs, where the diameter and spacing of Au NSs and the interaction distance between the Ca²⁺‐CsPbBr₃ QD and Au NS layers are modulated, according to the theoretical simulation of Finite‐difference time‐domain. As a result, the photoluminescence quantum yield of Ca²⁺‐CsPbBr₃ QD layer is improved from 31.5% to 73.3%. Finally, the luminance of Ca²⁺‐CsPbBr₃ QLEDs is improved from 16824 to 63931 cd m^–2 and external quantum efficiency (EQE) is improved from 4.2% to 10.5%. The radiative transition rate can be remarkably modulated from 0.7 × 10⁷ to 6.6 × 10⁷ s^–1. The enhancement in luminance and EQE are the best values in the LSPR modified perovskite QLEDs and the strategy offered in this work fits with other LEDs and optoelectrical devices.