Efficient and Stable Light-Emitting Diodes Enabled by Entropy-Driven Alloyed Perovskite Nanocrystals

Perovskite nanocrystals (PeNCs)-based light-emitting diodes (PeLEDs) are emerging as promising candidates for next-generation electroluminescent devices. However, their practical application is limited due to the poor stability of PeNCs. Here, we demonstrate an efficient and stable PeLED enabled by entropy-driven CsCd<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.1</sub>Pb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sub>Sr<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.1</sub>Br<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> PeNCs as emitter. Based on density functional theory (DFT) calculations with the Compound Energy Formalism (CEF) model, the simultaneous incorporation of multiple elements increases the entropy (S) of PeNCs, thereby enhancing their stability and suppressing lattice defects. The optimized PeLED achieves a maximum external quantum efficiency (EQE) of 22.2%, dramatically surpassing that (14.1%) of the control CsPbBr<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>-based device. More importantly, the device operating lifetime reaches 10 h, 14-fold higher than that of the control LED.