This study proposed a light trapping module to improve the light path in a solar cell in order to increase its light absorption efficiency. The microlens on a transparent substrate concentrates incident light into several light beams, which it leads into the optical channel on the back side. The optical channel is designed by coating highly reflective metals on the same transparent substrate, then an optical channel opening is made at the light beam focus so the light beams can pass through the optical channel and irradiate the solar cell. The light reflected by the solar cell is reflected again by the metal surface to the upper film of the solar cell, thus, increasing the absorption efficiency of the solar cell and reducing the film thickness of the solar cell to obtain better electrical properties. In this simulation the refractive index of the microlens was set as 1.43, the optical channel was 25 μm and the spacing was 0.27 mm, thus, the simulated absorption efficiency reached over 80%. The feasibility of this study was thus proved.

This study aimed to optimize the process parameters for the ultrasonic spraying of a nanooptical film coating on a large-area glass substrate, using the Taguchi experimental design. The key process parameters affecting spraying performance include the speed of the spray nozzle, flow rate of spray solution, airflow strength, spray height, and spray distance. The Taguchi quality characteristic used was the uniformity of light transmittance. With a glass substrate area of 52 cm2, the optimal process parameters for uniform spraying of silica solution were obtained via the Taguchi design method. The experiments confirmed that the optimal process parameters could effectively improve the uniformity of visible light transmittance; the S/N ratio of optical transmittance uniformity rose by approximately 2.79, transmittance reached 92.02%, and the transmittance uniformity was controllable to within 0.12%.