Fig. 4.

Optoelectronic characteristics of the PeLEDs. a Band alignment of each function layer in devices. b SEM cross-sectional image of the RbBr-rich <n>_Rb0.6 = 3 based devices. c I–V and L–V curves for pristine and RbBr-rich <n>_Rb0.6 = 3 devices. d EQE characteristics of pristine and RbBr-rich <n>_Rb0.6 = 3 devices. EL spectra of (e) pristine and (f) RbBr-rich <n>_Rb0.6 = 3 at different voltage bias. g The corresponding Commission Internationale de l’Echlaiage (CIE) coordinate of pristine and RbBr-rich <n>_Rb0.6 = 3 devices, and the inset image shows the electroluminescence of RbBr-rich <n>_Rb0.6 = 3 based PeLEDs