Yellow light-emitting diodes (LEDs) are widely utilized in high-quality lighting,light communication,indicator lamps,etc.Owing to their outstanding material properties and device performance,the metal halide perovskites have demonstrated a significant potential for LED applications.However,the perfor-mance of the yellow perovskite LEDs (PeLEDs) is inferior to that of their green and red counterparts,with the maximum external quantum efficiency (EQE) limited to ～3.1％.Further,a majority of the yellow PeLEDs are fabricated using the spin-coating methods.The current study reports the development of the yellow CsPbBr2I PeLEDs based on an all-vacuum deposition approach,which has been widely employed in the commercial organic LEDs (OLEDs).By controlling the co-evaporation rate of CsI and PbBr2,the growth kinetics of the perovskite layer are regulated to achieve a small grain size of～31.8 nm.Consequently,an improved radiative recombination rate (8.04 × 10-9 cm3/s) is obtained owing to the spatial confinement effect.The PeLEDs based on the optimal perovskite film demonstrate the yellow electroluminescence (574 nm) with a maximum EQE of ～3.7％ and luminance of～16,200 cd/m2,thus,representing one of the most efficient and bright yellow PeLEDs.Overall,this study provides a useful guideline for realizing the efficient PeLEDs based on the thermal evaporation strategy and highlights the potential of PeLED as an efficient and bright yellow light source.

Jinghui Li;Longbo Yang;Qingxun Guo;Peipei Du;Liang Wang;Xue Zhao;Nian Liu;Xuke Yang;Jiajun Luo;Jiang Tang

Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information,Huazhong University of Science and Technology,Wuhan 430074,China;Optics Valley Laboratory,Wuhan 430074,China;State Key Laboratory of Materials Processing and Die & Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China

科学通报（英文版）

[1]Jinghui Li;Longbo Yang;Qingxun Guo;Peipei Du;Liang Wang;Xue Zhao;Nian Liu;Xuke Yang;Jiajun Luo;Jiang Tang-.All-vacuum fabrication of yellow perovskite light-emitting diodes)[J].科学通报（英文版）,2022(02):178-185

CsPbBr2I

All,vacuum,fabrication,yellow,emitting,diodes,Yellow,are,widely,utilized,quality,lighting,communication,indicator,lamps,etc,Owing,their,outstanding,material,properties,device,performance,metal,halide,perovskites,have,demonstrated,significant,potential,applications,However,PeLEDs,inferior,that,green,red,counterparts,maximum,external,quantum,efficiency,EQE,limited,Further,majority,fabricated,using,spin,coating,methods,current,study,reports,development,deposition,approach,which,has,been,employed,commercial,organic,OLEDs,By,controlling,evaporation,CsI,growth,kinetics,layer,regulated,achieve,small,grain,size,Consequently,improved,radiative,recombination,cm3,obtained,owing,spatial,confinement,effect,optimal,film,electroluminescence,luminance,cd,thus,representing,one,most,efficient,bright,Overall,this,provides,useful,guideline,realizing,thermal,strategy,highlights,source

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