Tandem structure is able to improve the efficiency and stability of silicon-based thin film solar cells. The current matching of sub cells that limiting the efficiency of the tandem devices can be effectively improved by employing an interlayer. This paper introduces the structure, properties and materials of the intermediate reflector and tunnel junction in“a-Si∶H/mc-Si∶H”solar cells. Based on the theoretical foundation, the concept of“tunnel recombination reflector”short for the tunnel recombination junction as a light reflector is proposed and its working principle and materials selection are discussed. In the tandem devices, such interlayer not only plays the role of intermediate reflector that enhances light-trapping, but also optimizes the tunnel junction to improve charger carrier collection.