Optical properties and performance of pyramidal texture silicon heterojunction solar cells: Key role of vertex angles

Silicon heterojunction solar cells with pyramidal textured surfaces created by different etching conditions and their properties related to device efficiency (short-circuit current density and open-circuit voltage) are studied. An easy-to-apply model is proposed to estimate reflection losses, optimize the multilayer structure of the solar cell, and enhance photovoltaic conversion efficiency. The effects of etching treatments and pyramid geometry on overall device performance are discussed in detail. The study is completed by measurement of pyramid vertex angles of different textures. A difference from the expected and generally accepted theoretical value of 70.52 degrees is demonstrated and explained based on observation from high-resolution transmission electron microscopy. The multilayer structure of silicon heterojunction solar cells is optimized with respect to various pyramid vertex angles, using the designed optical model to minimize absorption and reflection losses.