Polymer Donors for High‐Performance Non‐Fullerene Organic Solar Cells

Abstract

Over the past three years, non-fullerene (NF) organic solar cells (OSCs) have been a focus of research and their power conversion efficiencies have been improved dramatically from ~6% to over 14%. In addition to innovations in NF acceptors, the ongoing development of polymer donors has contributed significantly to the rapid progress of NF OSC performance. This review highlights the polymer donors that enable high-performance NF OSCs. We first review the impressive photovoltaic devices results achieved by some of important classes of conjugated polymer systems in NF OSCs. Then, we discuss molecular design strategies as far as developing matching polymer donors for NF acceptors. Finally, we conclude with a brief summary and outlook for advances in donor polymers to fulfill future commercialization.

Design Principles and Synergistic Effects of Chlorination on a Conjugated Backbone for Efficient Organic Photovoltaics: A Critical Review

“…He and co‐workers synthesized two new NFAs, R10‐4Cl ( NFA15 ), and R12‐4Cl ( NFA16 ), with 10‐ring and 12‐ring‐fused cores as central “D” units and 2Cl‐DCI as terminal “A” units (Scheme ), respectively . Though, NFA15 and NFA16 demonstrated broader absorption (600–900 nm) range with an E g opt of 1.43 and 1.35 eV, respectively, owing to the increased fused core, but no considerable change was observed in the absorption profiles compared to the NFAs having central six‐ or eight‐membered heterocyclic core 5b. Single‐crystal X‐ray crystallographic results revealed that the NFA15 possess two distinct types of molecular packing, that is, one between the end groups of the adjacent molecules with a π–π stacking distance of 3.32 Å and the other between the two molecules with an angle of approximately 64.7° due to the close contact of S···O with a distance of 3.15 Å; hence, these resulted in an interpenetrated network for rapid charge transfer.…”

“…Therefore, simple structure molecular design strategies with low SC must be focused. 8.For the commercialization of OSCs, photoactive materials must exhibit several features, such as high efficiency, thickness tolerance, green solvent processing, air insensitivity, compatibility with the large‐area roll‐to‐roll processing technique, and excellent stability 5c,111. Most of the efficient Cl‐PVMs reported until now have demonstrated only one or two properties mentioned above.…”

Phthalimide‐Based High Mobility Polymer Semiconductors for Efficient Nonfullerene Solar Cells with Power Conversion Efficiencies over 13%

“…[19,20,[28][29][30][31][32][33][34][35][36][37][38][39][40] To the best of our knowledge, all these high-performance donor polymers are alternating donor-acceptor (D-A) type copolymers, which are exclusively based on benzo[1,2-b:4,5-b′]dithiophene (BDT) donor unit [41] copolymerized with a few acceptor counits, such as 5,6-difluoro-2-alkyl-2H-benzo[d] [1,2,3]triazole (FTAZ), [42] benzo[1,2-c:4,5-c′]-dithiophene-4,8-dione (BDD) [43] etc. [19,20,[28][29][30][31][32][33][34][35][36][37][38][39][40] To the best of our knowledge, all these high-performance donor polymers are alternating donor-acceptor (D-A) type copolymers, which are exclusively based on benzo[1,2-b:4,5-b′]dithiophene (BDT) donor unit [41] copolymerized with a few acceptor counits, such as 5,6-difluoro-2-alkyl-2H-benzo[d] [1,2,3]triazole (FTAZ), [42] benzo[1,2-c:4,5-c′]-dithiophene-4,8-dione (BDD) [43] etc.…”

Incorporation of Hydrogen Molybdenum Bronze in Solution‐Processed Interconnecting Layer for Efficient Nonfullerene Tandem Organic Solar Cells

“…Nonfullerene organic solar cells (OSCs) have been attracting great attentions due to their low voltage loss and high efficiency . Single‐junction nonfullerene OSCs have shown a power conversion efficiency (PCE) over 16% .…”