PDPP-TT

Bithiophene, Thienothiophene, Organic semiconducting materials, Low band-gap polymers, Organic photovoltaics, Polymer solar cells, OFETs.

The exceptional high mobility of this polymer of up to 10 cm2/Vs [2] via solution-processed techniques, combined with its intrinsic air stability (even during annealing) has made PDPP2T-TT-OD of significant interest for OFET and sensing purposes.
While the highest mobilities require exceptional molecular weights of around 500 kD (and with commensurate solubility issues), high mobilities in the region of 1-3 cm2/Vs can still be achieved with good solution-processing at around 250 kD.

Example OFET characteristics for DPP-DTT (M313) solution processed from chlorobenzene on a 300 nm SiO2 substrate treated with OTS. Output characteristic (top left), transfer curves (top right), mobility fitting (bottom left) and calculated mobility.

Although shown as a promising hole-mobility polymer for OFETs, when used as the donor material in a bulk heterojunction photovoltaic (with PC70BM as the acceptor), initial efficiencies of 1.6% were achieved for DPP-DTT. The low device metrics were attributed to poor film morphology. However, a higher efficiency of 6.9% was achieved by using thicker film (220 nm).
PDPP2T-TT-OD has also recently been used successfully as an active-layer dopant material in PTB7-based devices. An improvement in device performance was observed, with average efficiencies increasing from 7.6% to 8.3% when the dopant concentration of DPP-DTT was 1 wt%. The use of DPP-DTT as a high-mobility hole-interface layer for perovskite hybrid devices has also been investigated.

DPP-DTT is a high mobility p-type polymer, suitable for OFET and sensing and photovoltaic applications.