Integration of Solar Cell with TN-LC Cell for Enhancing Power Characteristics

Abstract

This study improves the output power and brightness characteristics of a translucent hydrogenated amorphous silicon (a-Si:H) solar cell by integrating the solar cell with a novel twist nematic (TN) liquid crystal (LC) cell incorporating a sub-wavelength metal grating (SWMG) polarization beam splitter (PBS). In this study, a SWMG-PBS is used to replace not only the sheet polarizers in the conventional TN-LC cell, but also the upper and lower alignment layers and transparent electrodes. Therefore, a translucent a-Si:H solar cell integrating with the novel TN-LC cell with the SWMG-PBS could improve power efficiency and durability in UV ray environment. The experimental results show that the transmittance gap between the “on” and “off” states of the enhanced translucent a-Si:H solar cell / novel TN-LC cell is of the order of 26.6% on 800 nm, 6.3% on 400 nm and 2.7% on 510 nm. Moreover, it is shown that the novel TN-LC cell increases the maximum electrical power developed by the translucent a-Si:H solar cell and improves its power conversion efficiency by 0.209% in the “off” state and 0.417% in the “on” state. In other words, the gain factors, the power efficiency of the novel TN-LC cell with translucent a-Si:H solar cell divided by the power efficiency of the standalone translucent solar cell, are determined to be 1.101 (or 110.1 %) in the “off” state and 1.201 (or 120.1 %) in the “on” state. As a result, the proposed device represents an ideal solution for building integrated photovoltaic (BIPV) systems, automobile industry applications, and many other adjustable brightness photovoltaic applications.