ZnO:Er, Li film prepared by sol–gel method and its properties of converting both UV and NIR light to visible light

ZnO:Er, Li light conversion film has been successfully fabricated by sol–gel method. XRD measurement demonstrated the successful incorporation of Er 3+ and Li + into ZnO films. The as-grown film co-doped with 2% Er 3+ and 3% Li + is featured with a transmittance of about 86.8% in the range of 400–900   nm. Moreover, the film exhibits a visible light emission either being excited by 355   nm or 980   nm. Due to its relatively high transmittance characteristics and promising properties of converting both UV and NIR light to visible light, the developed film is considered to have a potential application in novel light conversion devices including solar cells.