Triplet state formation in photovoltaic blends of DPP-type copolymers and PC71 BM.

The exciton dynamics in pristine films of two structurally related low-bandgap diketopyrrolopyrrole (DPP)-based donor-acceptor copolymers and the photophysical processes in bulk heterojunction solar cells using DPP copolymer:PC71 BM blends are investigated by broadband transient absorption (TA) pump-probe experiments covering the vis-near-infrared spectral and fs-μs dynamic range. The experiments reveal surprisingly short exciton lifetimes in the pristine poly-mer films in conjunction with fast triplet state formation. An in-depth analysis of the TA data by multivariate curve resolution analysis shows that in blends with fullerene as acceptor ultrafast exciton dissociation creates charge carriers, which then rapidly recombine on the sub-ns timescale.

Synthesis and characterization of anthracene derivative for organic field-effect transistor fabrication.

Here we report on the synthesis and characterization of anthracene derivative for solution processable organic field-effect transistors. The transistor devices with bottom-contact geometry provided a maximum field-effect mobility of 3.74 x 10(-4) cm2 V(-1) s(-1) as well as current on/off ratio of 5.

Diethynylbenzene-based liquid crystalline semiconductor for solution-processable organic thin-film transistors.

We report here the synthesis and characterization of novel diethynylbenzene-based liquid crystalline semiconductor (P1) for organic thin-film transistors (OTFTs). Compound P1 was synthesized by the Sonogashira coupling reaction between 2-bromo-5-(4-hexylthiophen-2-yl)thieno[3,2-b]thiophene and 1,4-bis(dodecyloxy)-2,5-diethynylbenzene. Top contact OTFTs were fabricated by spin casting with 2 wt% solution of P1 in chloroform and their best performance, which exhibited a hole mobility of 4.