Absorption Enhancement in Thin-Film Solar Cells using Integrated Photonic Topological Insulators

We propose a new method to trap sunlight in the active layer of thin-film solar cells. In this method, a photonic crystal, which realizes photonic topological insulators (PTI), is integrated inside the solar cell to trap sunlight in the active layer. PTIs with edge states in their boundaries, confine sunlight around their bulks and enhanced the absorption of the solar cell. The performance of the structure is investigated numerically using full-wave analysis. Numerical results show that the proposed method enhances the absorption of the solar cell in a wide range of wavelengths, as well as different angles of the incident light. The numerical calculations show that the short circuit current of the solar cell with PTI increases by 28 % in comparison with the simple solar cell.