Reduced thermal effect of AZO/Cu/AZO infrared filter film for solar cell

In this work, infrared filter property of aluminum doped ZnO (AZO) films prepared on glass substrates with different Ar flow rate by magnetron sputtering was studied. Then Cu was chosen to produce AZO/Cu/AZO sandwich films to further improve its infrared filter property for high transmittance within 380-1100 nm and low transmittance within 1100-2500 nm. The results showed that AZO film had a maximum transmittance over 85% in the region between 380 nm and 1100 nm and a lowest transmittance of 29.70% between 1100 nm and 2500 nm. While AZO/Cu/AZO sandwich film had a maximum transmittance of 80.95% between 380 nm and 1100 nm and its minimum transmittance was 14.61% between 1100 nm and 2500 nm. By using AZO/Cu/AZO sandwich glass as a cover of silicon solar cell, its working temperature showed a less increase of 10.61 degrees C after 3.5 h under an irradiation of 0.42 sun compared with that where a standard glass was used. This was because that Cu greatly increased the carrier concentration in the sandwich that led to a stronger carrier absorption in infrared wavelength region, so that a reduced thermal effect of the solar cell was obtained.