A spectrally selective metal mesh coating for photovoltaic/thermal applications

In this work, a nano-scale metal (silver) mesh coating was proposed for the photovoltaic/thermal applications (PV/T), it has high transmittance in the solar radiation band (0.3-2.5 μm) and high reflectivity in the infrared band (2.5-25 μm). When combined with PV/T absorber that has high absorption/emission in the full band (0.3-25 μm), it can guarantee the spectral selection characteristics of high absorptivity in the solar band and low emissivity in the infrared band, which can significantly reduce the radiation heat loss of PV/T. Based on the finite-difference time domain method, the effects of mesh period, width and height of metal mesh coatings on the spectral characteristics were simulated and analyzed. The results show that when the period of the nano-metal mesh is 500nm, the height is 50 nm, and the width is 30 nm, the transmittance in the solar band reaches 0.90, and the mid-infrared reflectance reaches 0.88. Compared with the existing ITO coating, the solar radiation transmittance of the metal mesh coating is increased by 20%, the infrared reflectance is increased by 24%, and the sheet resistance (5.3 Ω Sq-1) is reduced 47%.