High-efficiency micromorph silicon solar cells with in-situ intermediate reflector deposited on various rough LPCVD ZnO
Light management using intermediate reflector layers (IRL) and advanced front transparent conductive oxide (TCO) morphologies is needed to rise the short-circuit current density (Jsc) of micromorph tandem solar cells above 14 mA/cm2. For micromorph cells deposited on surface-textured ZnO layers grown by low-pressure chemical vapour deposition (LPCVD), we study the interplay between the front TCO layer and the IRL and its impact on fill factor and current matching conditions. The key role of the angular distribution of the light scattered by the front LPCVD ZnO layer is highlighted. A micromorph cell with 11.1% stabilized conversion efficiency is demonstrated. By increasing the bottom cell thickness and adding an antireflection coating, a Jsc value of 13.8 mA/cm2 is achieved. This remarkably high Jsc yields 13.3% initial conversion efficiency.