Polymer Non-Fullerene Solar Cells of Vastly Different Efficiencies for Minor Side-Chain Modification: Impact of Charge Transfer, Carrier Lifetime, Morphology and Mobility

The performance of the 11.25% efficient PBDB-T : ITIC system degraded to 4.35% after a minor side-chain modification in PBDB-O : ITIC. In this study, the underlying reasons behind this vast difference in efficiencies are investigated.