Unsubstituted Benzodithiophene-Based Conjugated Polymers for High-Performance Organic Field-Effect Transistors and Organic Solar Cells

Abstract

Unsubstituted benzo[1,2-b:4,5-b']dithiophene (BDT) was used to construct a high-performance conjugated polymer with 5,6-difluoro-4,7-bis[4-(2-octyldodecyl)thiophene-2-yl]benzo[c][1,2,5] thiadiazole (DTFFBT), named PBDT-DTFFBT. The polymer shows the low-lying highest occupied molecular orbital (HOMO) energy level (-5.40 eV) and a broad absorption spectra with strong vibronic absorption peak. Pure polymer films exhibit good crystallinity and edge-on orientation, partially attributed to the BDT units without any side chains, and as a result, the corresponding thin-film transistor showed excellent hole mobility over 1 cm(2) V(-1) s(-1). Interestingly, a well-distributed nanofibrillar polymer aggregation with face-on orientation was obviously formed when blending with PC71BM, which was in favor of the charge transportation. Consequently, the bulk heterojunction polymer solar cells based on the blends showed high power conversion efficiency of 9.29% with large short-current density (14.56 mA cm(-2)) and high fill factor (0.751) without any process additives or thermal annealing.

High‐Efficiency Polymer Solar Cells Over 13.9% With a High VOC Beyond 1.0 V by Synergistic Effect of Fluorine and Sulfur

“…It exhibits a defined absorption profile with two strong peaks at about 537 and 577 nm in solution, which belong to charge transfer transition and inter‐chain aggregation absorption, respectively. It is inferred that there should be strong intermolecular aggregation in solution . And the film state absorption spectrum of PBTA‐PSF was red‐shifted compared to that of the solution.…”

Synthesis of 1,6‐didecylnaphtho[1,2‐b:5,6‐b']difuran‐based copolymers by direct heteroarylation polymerization

“…DHAP has been successfully applied to the synthesis of thiophene containing conjugated polymers including benzodithiophene (BDT) [19][20][21] which has been used in the synthesis of some of the best performing OSC materials to date. [22][23][24] In an effort to improve upon the properties of BDTbased polymers, several groups have evaluated the impact of substitution with oxygen to produce the analogous benzodifurans. [25][26][27][28][29][30] Although furan is isoelectronic to thiophene, it has a smaller Dewar resonance energy.…”

Temperature‐Dependent and Aggregation‐Breaking Strategy for Benzodifuran‐Constructed Organic Solar Cells

“…The main strategies have been reported to improve the PCE as following aspects: 1) Alternating electron donors (D) and deficient acceptors (A) in the backbone of copolymers is the most successful materials designing strategy for high PCE . Up to now, most reported works have been devoted to design novel‐conjugated polymers based on the 2D π‐extended donor units, such as fluorene, carbazole, indacenodithiophene (IDT), dithieno[2,3‐d:2’,3’‐d’]benzo[1,2‐b:4,5‐b’]dithiophene (DTBDT) and benzo[1,2‐b:4,5‐b’]dithiophene (BDT), and different acceptor units . In addition, BDT moieties take up a large proportion in organic semiconductor because of the rigid and planar structure, easy modification, and the high mobility of its related polymers.…”