Fullerene-Functionalized Poly(3-hexylthiophene) Additive Stabilizes Conjugated Polymer–Fullerene Blend Morphologies AITranslate

Basic Information:

DOI：https://doi.org/10.1021/acsapm.1c00566

Chinese Library Classification Number:

Citation Information:

Organic photovoltaics are again gaining traction as device power conversion efficiencies have increased substantially over the last two years. Despite these improved efficiencies, long-term device stability remains a challenge because the physical blend of an electron-donor and -acceptor in the active layer can phase-separate into larger domains over time. Copolymers that are miscible with both the donor and acceptor can stabilize the active layer blend morphology, but these additives are often tailored to match the specific donor/acceptor blend. We demonstrate herein that a single copolymer containing a conjugated poly(3-hexylthiophene) backbone and fullerene-functionalized side chains serves as a general blend stabilizer. Optical microscopy revealed that phase separation was suppressed in three different conjugated polymer/fullerene blends (PTB7, PTB7-Th, and PffBT4T-2OD with PC71BM) when annealed with the copolymer in thin films. Moreover, phase separation was suppressed in photovoltaic devices containing PffBT4T-2OD:PC71BM with the copolymer in the active layer. We also investigated factors beyond morphology that affect the initial power conversion efficiency, which was lower for devices with the copolymer. Overall, our results demonstrate that a single fullerene-functionalized poly(3-hexylthiophene) copolymer additive suppresses phase separation in multiple conjugated polymer/fullerene thin film blends as well as in a photovoltaic device.