Complementary Absorption Pseudo-Ternary Blend Containing a Y-Series Block Copolymer Acceptor for Indoor and Outdoor All-Polymer Photovoltaics

초록

All-polymer photovoltaics (all-PPVs) that operate under both indoor and outdoor lighting conditions require active layers with appropriately adjusted optical-absorption ranges. However, the optical absorption of a conventional donor-acceptor binary blend is restricted to the combined absorption bands of its components. Herein, a new conjugated block copolymer (CBC) acceptor, b-PYT, is designed by integrating polymer acceptor blocks of wide and narrow bandgaps in a single structure. Such combination results in the wide absorption range (550-850 nm) of b-PYT that matches the emission of both artificial and solar light. The b-PYT CBC acceptor is more crystalline than the corresponding random terpolymer, r-PYT, owing to improved interactions between its macromolecular acceptor units. Despite exhibiting slightly inferior outdoor performance compared to that of devices using the homopolymer BTTP-T, the PM6:b-PYT-based devices deliver superior power conversion efficiency (PCE) under indoor light-emitting diode (LED) light owing to better matched absorption and emission spectra of b-PYT and a cold white LED, respectively. Additionally, it is worth highlighting that PM6:b-PYT-based all-PPVs can maintain approximately 87% of the initial PCE even after 600 min of thermal aging at 150 degrees C, which demonstrates the superior thermal stability compared with those of all-PPVs that use traditional binary active layers. The block copolymer acceptor with broad absorption, b-PYT, is synthesized by combining narrow- and medium-bandgap segments, BTTP-T and BTP-T. This design of b-PYT enables the corresponding photovoltaic devices to operate effectively under AM1.5G and white light-emitting diode illumination with enhanced thermal stability. This approach shows promise in developing high-performance materials for dual-function photovoltaic devices for efficient indoor and outdoor applications.image (c) 2023 WILEY-VCH GmbH

키워드