Investigation of additive structure of optical layers for increasing the efficiency of photovoltaic cells

Abstract

Solar energy is one of the most promising renewable energy sources, thus photovoltaic (PV) technologies have rapidly penetrated the market in recent years. However, the intrinsic performance of PV is limited by light absorption and cost, thus investigation of a variety of new designs to improve the efficiency of light absorption as well as provide more competitive prices is required. Research has explored the development of new optical designs to optimise the effectiveness of light absorption, focused on boosting the PV efficiency of solar cells and reducing surface reflectivity. One method to give the light more opportunity to be absorbed is light trapping: designing solar cells such that light that enters the cell is optically guided to stay within the cell, where it can be absorbed. In light trapping, light coming into the structure is scattered at a high angle, leading to light bouncing off multiple times so there will be increasing optical path length, which increases light absorption efficiency, hence generating more power from the same latent solar radiation available at the site. This project experiments with the addition of an optical layer to be used with any PV panels in order to obtain high maximum power. Firstly, multi-lensed films (Rowlux) were chosen as an affordable choice with good optical properties (one Rowlux typically obtains a 9.1% power gain during a half day). Also, different 3D printed optical structures were tested in order to show potential improvements, including a structure coated with fluorescent dye, and another with different lens-let arrays, showed no significant result.