Solution‐Processed Rhenium Oxide: A Versatile Anode Buffer Layer for High Performance Polymer Solar Cells with Enhanced Light Harvest

The interfaces between the photoactive layer and the two contact electrodes are vitally important for the device performance and long term stability of the PSCs. Due to the inevitable potential loss caused by the Fermi level alignment between the donor and acceptor, it is crucial to establish ohmic contacts at both electrodes for effi cient charge collection and transportation at the interfaces. Transparent conducting indium tin oxide (ITO) is a popular bottom electrode in PSCs. Unfortunately, it does not possess the desirable work function for the PSCs. Much