Efficient and Stable Perovskite Light-Emitting Diodes Enabled by Oriented Growth Regulation

Metal halide perovskites have demonstrated remarkable progress in optoelectronic applications, including solar cells and light-emitting diodes (LEDs). However, the long-term stability of perovskite LEDs (PeLEDs) remains a critical challenge, impeding their practical applications and commercialization. Herein, we regulate the growth kinetics of perovskites in liquid-solid stages by introducing 2,3,4,5, 6-pentafluorophenylphosphonic acid (PFBPA) into the precursor solution. The PFBPA molecules will create a protective passivation layer by coordinating with uncoordinated lead (Pb<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup>) on the perovskite surface, which regulates the growth of perovskite crystals during the liquid-solid stages and results in the formation of uniform perovskite films with reduced grain size. Moreover, the coordination of PFBPA with Pb<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> also improves the moisture resistance of perovskites, favoring the operational stability of devices. The resulting PeLED devices achieved a maximum brightness of 12426 cd m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup>, a peak external quantum efficiency (EQE) of 22.6%, and a remarkable operational stability with a half-lifetime exceeding 1187 hours at initial luminance of 100 cd m-2.