Intrinsic traps in organic semiconductors can be eliminated by trap-filling with F4-TCNQ. Photovoltaic tests show that devices with F4-TCNQ at parts per thousand concentration outperform control devices due to an improved fill factor. Further studies confirm the trap-filling pathway and demonstrate the general nature of this finding.

A series of five thionated naphthalene diimides (NDIs) with linear alkyl chains was synthesized and the optoelectronic, self-assembly, and device properties were studied. When tested in organic thin-film transistors, the electron mobilities of the thionated derivatives are three orders of magnitude higher than the non-thionated parent analogue, with the highest mobility measured for cis-S2 (µ max = 7.5 × 10 -2 cm 2 V -1 s -1 ). In contrast to branched chain PDIs and NDIs, the electron mobility does not increase appreciably with degree of thionation, and the average mobilities are quite consistent ranging from 3.9 × 10 -2 to 7.4 × 10 -2 cm 2 V -1 s -1 for one to three sulfurs.18 been previously reported for the compound. 37 This discrepancy may be due to slight differences in device configuration and fabrication conditions, or in compound purity. The S3 device annealed at 150 o C also showed no performance, possibly due to the lower thermal stability of the higher thionated compounds (vide supra). Devices could not be prepared from trans-S2 or S4 due to their poor solubility and film-forming ability.

Conjugated block copolymers, where each block contains a unique electroactive group, allows selective block-oxidation in solution, which promotes reversible, redox-controlled self-assembly.