Organic light-emitting diodes (OLEDs) have been gradually matured in panel displays and solid state lightings,such as portable electronic devices and OLED television.However,improving their luminan ce efficiency and stability for real applications remains a challenge.In this pa per,we examine the electron injection performance in the OLED structure of ITO/N PB/Rubrene/NPB/DPVBi/Alq₃/LiF/Al and apply the photoelectric material CdS as i nsertion layer between Alq_3and LiF for comparison.Results show that a 0.3nm -thick CdS layer inserted between Alq_3and LiF effectively enhances the perf ormance of the device.Meanwhile,the CIE chromaticity coordinates of the devices are well whthin the white region when bias voltage changes from 7V to 14V.Furt hermore,we investigate the influence of the thick- ness of CdS thin film on perfor mance of the device by taking the film thickness as 0.05nm,0.1nm, 0.3nm,0.5nm and 0.7nm.These experimental results indicate when the thickness of the insert ed CdS layer is 0.1nm,the greatest performance enhancement of the OLED can be o btained.The maximum current efficiency and luminance for the device with 0.1nm -thick CdS insertion layer reach 9.09cd/A at 7V and 16370cd/m^2at 14V.respectively,which are enhanced to 1.76times and 2.42time re spectively.compared with the device without CdS insertion layer.