Synergetic or colliding effects on the solar-electric conversion efficiency from light-trapping structured surfaces: Coupling optical-electrical features of bifacial solar cells

摘要

Light-trapping structures play an important role in the application of solar cells due to their ability to enhance absorption. A dilemma related to comprehensive consideration of augmenting the light-trapping ability of surfaces of solar cells and suppressing recombination tendency induced by improper design of structured surfaces to keep in mind the ultimate goal of achieving as high solar-electric conversion efficiency of commercial photovoltaic cells as possible. This work is aimed at investigating the coupling optical-electrical properties of bifacial heterojunction with intrinsic thin-layer (HIT) solar cells on which multiscale pyramid microstructures are fabricated. Based on the results of coupling investigation, a tradeoff between optical and electrical properties are achieved with pyramids of 3-5 mu m. The highest power conversion efficiency (PCE) locates at solar cells with pyramids of 3-5 mu m. The best PCE amounts respectively to 23.46% and 21.85% with the frontal and rear illumination and the bifacial utilization can be enhanced is up to 93.4%. The output properties are superior to those of PV cells in the baseline. The interconnection between the temperature coefficient of PV conversion efficiency and dimensions of the microstructured surfaces is studied. The influences of different light-trapping structures on the ability of photon absorption and the recombination of carriers of solar cells are characterized. This work provides the guideline for selecting more appropriate structures with both benign optical and electrical properties to enhance the performance of solar cells.