Supramolecular Assembly of H-Bonded Side-ChainPolymers Containing Conjugated Pyridyl H-AcceptorPendants and Various Low-Band-Gap H-DonorDyes Bearing Cyanoacrylic Acid Groups forOrganic Solar Cell Applications

摘要

Novel supramolecular side-chain polymers were constructed by complexa-tion of proton acceptor (H-acceptor) polymers, i.e., side-chain conjugated polymersPl—P2 containing pyridyl pendants, with low-band-gap proton donor (H-donor) dyesSl—S4 (bearing terminal cyanoacrylic acids) in a proper molar ratio. Besides uniquemesomorphic properties confirmed by DSC and XRD results, the H-bonds of supra-molecular side-chain structures formed by pyridyl H-acceptors and cyanoacrylic acidH-donors were also confirmed by FTIR measurements. H-donor dyes Sl—S4 in solidfilms exhibited broad absorption peaks located in the range of 471-490 nm with opti-cal band-gaps of 1.99-2.14 eV. Furthermore, H-bonded polymer complexes P1/S1—P1/S4 and P2/S1—P2/S4 exhibited broad absorption peaks in the range of 440-462 nmwith optical band-gaps of 2.11-2.25 eV. Under 100 mW/cm2 of AM 1.5 white-light illu-mination, the bulk heterojunction polymer solar cell (PSC) devices containing anactive layer of H-bonded polymer complexes P1/S1—Pl/S4 and P2/S1—P2/S4 (as elec-tron donors) mixed with [6,6]-phenyl C_(61)butyric acid methyl ester (i.e., PCBM, as anelectron acceptor) in the weight ratio of 1:1 were investigated. The PSC device con-taining H-bonded polymer complex P1/S3 mixed with PCBM (1:1 w/w) gave the bestpreliminary result with an overall power conversion efficiency (PCE) of 0.50%, ashort-circuit current of 3.17 mA/cm~2, an open-circuit voltage of0.47 V,and a fill factorof 34%.