POS5-0925
Highly Stretchable Bulk Heterojunction Thin Films for Stretchable Organic Photodetectors
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Soyoon Kim (Ewha Womans University)
Co-Author(s)
Abstract
Despite the enhanced photoinduced charge carrier generation enabled by bulk heterojunction (BHJ) thin films composed of polymeric electron donors and small-molecule electron acceptors, the intrinsic fragility of small-molecule electron acceptors limits the mechanical compliance of BHJ thin films and deteriorates the performance of stretchable organic photodetectors (OPDs) under mechanical deformation. In this study, we employed two multiblock copolymers containing semiconducting poly(3-hexylthiophene) (P3HT) and elastomeric moieties synthesized via Suzuki–Miyaura catalyst-transfer polymerization, which afforded precise control over molecular architecture and elastomer content. These multiblock copolymers were used as electron donors and blended with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) electron acceptors to form BHJ photoactive layers. Unlike conventional P3HT:PC71BM thin films exhibiting negligible stretchability, the multiblock copolymer BHJ thin films showed significantly enhanced mechanical deformability, with a maximum crack onset strain (COS) exceeding 250% despite containing mechanically fragile PC71BM acceptors. Notably, these BHJ thin films enabled high-performance OPDs with responsivity (R) and specific detectivity (D*) exceeding 300 mA W−1 and 1 × 1012 Jones, respectively, under zero-bias operation. The exceptional stretchability and photodetection performance were attributed to the formation and preservation of short-range-ordered face-on crystallites, which enabled efficient charge generation and transport while reducing the amount of fragile PC71BM required in the BHJ thin films compared with conventional P3HT systems. These results demonstrate that the precise synthesis of semiconducting multiblock copolymers represents an effective molecular design strategy for simultaneously achieving high photodetection performance and mechanical compliance in BHJ systems, providing a promising pathway toward wearable and stretchable optoelectronic applications.
