This paper describes the synthesis and application of βTPB6 and βTPB6-C as electron acceptors for organic solar cells. Compound βTPB6 contains four covalently bonded PDIs with a BDT-Th core at the β-position. The free rotation of PDIs renders βTPB6 with varying molecular geometries. The cyclization of βTPB6 yields βTPB6-C with high rigidity of the molecular geometry and enlarged conjugated skeleton. The inverted solar cells based on βTPB6-C and PTB7-Th as the donor polymer exhibited the highest efficiency of 7.69% with V oc of 0.92 V, J sc of 14.9 mAcm −2 , and FF of 0.56, which is 31% higher than that for βTPB6 based devices. The larger fraction of βTPB6-C and PTB7-Th than that of βTPB6:PTB7-Th in a blend film takes a face-on orientation packing pattern for π-systems that benefits the charge transport and hence higher PCE value than that for βTPB6:PTB7-Th. It was also found that a proper DIO:DPE additive further enhances this trend, which results in an increase of the PCE value for βTPB6-C:PTB7-Th while decreasing the PCE value for βTPB6:PTB7-Th.

A critical issue in developing high-performance organic light-emitting transistors (OLETs) is to balance the trade-off between charge transport and light emission in a semiconducting material. Although traditional materials for organic...

The lack of design principle for developing high-performance polymer materials displaying strong fluorescence and high ambipolar charge mobilities limited their performance in organic light-emitting transistors (OLETs), electrically pumped organic laser, and other advanced electronic devices. A series of semiladder polymers by copolymerization of weak acceptors (TPTQ or TPTI) and weak donors (fluorene (F) or carbazole (C)) have been developed for luminescent and charge transporting properties. It was found that enhanced planarity, high crystallinity, and a delicate balance in interchain aggregation obtained in the new copolymer, TPTQ-F, contributed to high ambipolar charge mobilities and photoluminescent quantum yield. TPTQ-F showed excellent performance in solution-processed multilayered OLET devices with an external quantum efficiency (EQE) of 5.3%.

The configuration of the molecule–electrode contact region plays an important role in determining the conductance of a single-molecule junction, and the variety of possible contact configurations have yielded multiple conductance values for a number of molecular families. In this report, we perform simultaneous conductance and electromechanical coupling parameter measurements on a series of oligophenylene–dithiol single-molecule junctions. These molecules show two distinct conductance values, and by examining the conductance changes, the electromechanical coupling, and the changes in the I–V characteristics coupled with a combination of analytical mechanical models and density functional theory (DFT) structure calculations, we are able to determine the most-probable binding configuration in each of the conductance states. We find that the lower-conductance state is likely due to the thiols binding to each electrode at a gold top site, and in the higher-conductance state, the phenylene π orbitals interact with electrodes, drastically modifying the transport behavior. This approach provides an expanded methodology for exploring the relationship between the molecule–electrode contact configuration and molecular conductance.