Synthesis and Light Emitting Properties of Dithieno[3,2-b:2',3'-d]Thiophene (DTT) Containing Conjugated Polymers for Electroluminescene Devices and Polymer Solar Cells.

Dithieno[3,2-b:2',3'-d]thiophene (DTT) has emerged as an important building block in the synthesis of a wide variety of optoelectronic materials. Two new DTT containing conjugated polymers, poly(dithieno[3,2-b:2',3'-d]thiophenevinylene-alt-9,9-diethylhexyl-2,7-fluorenediyl vinylene) (FLU-DTT) and poly(dithieno[3,2-b:2',3'-d]thiophenevinylene-alt-2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene) (MEH-DTT), were designed and synthesized. The photoluminescence (PL) spectra of FLU-DTT and MEH-DTT in film exhibit maximum emission peaks at 538 and 602 nm, respectively. The MEH-DTT polymer film showed far more red-shifted maximum electroluminescene (EL) emission at 650 nm. The photovoltaic device was also fabricated using MEH-DTT and PC71BM as active layer and it showed power conversion efficiency (PCE) for the polymer solar cell (PSC) as 0.59% under AM 1.5 G (100 mW/cm2) conditions.