High-Efficiency Organic Solar Cells enabled by Nonfullerene Acceptors with Varying Alkyloxy Substitution Position of phenyl Outer Side Chains

Two isomeric molecules named m -BTP-OEH and p -BTP-OEH were developed by attaching a 2-ethylhexyloxyl substituent at the meta - or para -position of its phenyl side chains and a PCE promotion from 17.23% to 18.02% was achieved.