UV- and NIR-blocking properties of ZnO/ATO bilayer films prepared by RF magnetron sputtering

Abstract

Films with ultraviolet (UV) and near-infrared (NIR) blocking properties can be used to protect against UV and heat radiation, thus prolonging the operating life of photovoltaic devices. Being wide band-gap semiconductors, ZnO films can absorb UV light and antimony doped tin oxide (ATO) films can play the role of defending against the NIR light with low electrical resistivities. In this work, the bilayer films of ZnO overlayed by ATO are sputtered by radio-frequent (r.f.) magnetron sputtering, and the growth rules of ATO on ZnO film are studied comprehensively by adjusting parameters including the sputtering power, pressure, gas flow rate ratio of O 2 /Ar and sputtering time. Eventually, a bilayer film with 200 nm thick ZnO layer and 400 nm thick ATO layer is fabricated and shows about 96% UV-blocking (from 280 nm to 380 nm), about 66% NIR-blocking (from 1100 nm to 2500 nm) while maintains about 80% light transmittance (from 380 nm to 1100 nm) after annealing in the nitrogen atmosphere at 500 °C for 1 h. This transparent bilayer film with UV and NIR double blocking functions can be potentially used in organic solar cells. • ZnO/ATO bilayers with UV and near IR double blocking functions were produced. • The bilayers of ZnO overlayed by ATO were deposited by r.f. magnetron sputtering. • 96% UV-blocking (280–380 nm) was got from ZnO (200 nm)/ATO (400 nm) bilayer. • 66% NIR-blocking (1100–2500 nm) and 80% transmission (380–1100 nm) were also gained.