Micro Array of Fresnel Lenses Concentrator Photovoltaic System on Crystalline Silicon Solar Cells

Using the combination of the electron beam lithography (EBL), the reactive ion etching (RIE) and the Polydimethylsiloxane (PDMS) replica molding techniques the author have fabricated the micro-array of PMMA/SiO<sub>2</sub> Fresnel lenses concentrator photovoltaic CPV-system for high efficiency silicon solar cells. Fresnel rings units containing eleven concentric rings were created on PMMA layer with the outermost Fresnel ring having an external diameter of 45.24μm and are located ≈200μm away from each other. The CPV-system consists ≈3025-Fresnel lens units per cm<sup>2</sup> with approximate focal length <i>f</i> of ≈45 μm and the optical concentration ratio (OCR) of ≈95X. The resulting CPV-system when placed at the location ≈45 μm from the surface of silicon solar cells (Si-Solar cells) increased the open circuit voltage <i>V</i><i><sub>OC</sub></i> by 17.9 mV, short current density <i>J</i><i><sub>SC</sub></i> by 5.2 mA/cm<sup>-2</sup> and the maximum power <i>P</i><i><sub>max</sub></i> by 11.42 mW. Meanwhile, this system enhanced power conversion efficiency of Si-Solar cells by 0.17% and decreased the series resistance <i>R</i><i><sub>s</sub></i> of Si-Solar cells by 0.81 Ω.