Subtle Side Chain Triggers Unexpected Two-Channel Charge Transport Property Enabling 80% Fill Factors and Efficient Thick-Film Organic Photovoltaics
Graphical abstract
To clearly show how important the impact of side chains on organic solar cells (OSCs) is, we designed three acceptors IDIC-CxPh (x = 4, 5, or 6) via subtle side-chain regulation. Despite this small change, significant distinctions were detected. IDIC-C4Ph devices achieve an optimal efficiency of 13.94% under thermal annealing, but thermal-assistant solvent-vapor annealing hugely suppresses the efficiencies to 10%. However, the C6Ph side chain endows extremely disordered stacking orientations, generating moderate efficiencies of ~12.50%.
