Comment on “Enhanced Charge Selectivity via Anodic-C₆₀ Layer Reduces Nonradiative Losses in Organic Solar Cells”

Understanding interface-related phenomena is important for improving the performance of thin-film solar cells. In ACS Appl. Mater. Interfaces 2021, 13, 12603–12609, Pranav et al. report that incorporating a thin C60 interlayer at the MoO3 anode results in reduced surface recombination of electrons, which is ascribed to a decreased electron accumulation near the anode on account of an increased built-in voltage. Here, we offer an alternative explanation: the introduction of a C60 interlayer renders the MoO3 contact Ohmic. The reduced anode barrier simultaneously increases the built-in voltage, minimizes nonradiative voltage losses upon the extraction of majority carriers (holes), and suppresses minority-carrier (electron) surface recombination, the latter being the result of hole accumulation and associated band bending near the Ohmic hole contact. We therefore argue that Ohmic contact formation suppresses both majority- and minority-carrier surface recombination losses, whereas the built-in voltage per se does not play a major role in this respect.