Thermally Stable Dibenzo[def,mno]chrysene-Based Polymer Solar Cells: Effect of Thermal Annealing on the Morphology and Photovoltaic Performances

Abstract

The photovoltaic performances of dibenzo[def,mno]chrysene-based polymer (poly(2,2'-thiophenevinylenthiophene-4,10-[6,12-bis(2-decyltetradecyloxy)-dibenzo[def,mno]chrysene]) ( PTVTC) or poly( 4,10-bithiophene-6,12-bis( 2-decyltetradecyloxy)-dibenzo[def, mno] chrysene) ( PTTC)) solar cells as a function of thermal annealing temperatures from 100 to 180 degrees C are reported. Interestingly, the solar cells with PTTC containing two thiophene units, have superior thermal stability compared to the PTVTC:[6,6]-phenyl-C71-butyric acid methyl ester ( PC71BM) solar cells, in which the PTVTC has two thiophene and vinyl groups. Atomic force microscopy, transmission electron microscopy, and X-ray diffraction demonstrate that morphological stability of PTTC: PC71BM blend films conduces thermally stable photovoltaic performances of PTTC solar cells. Therefore, the PTTC: PC71BM bulk heterojunction solar cells have highly stable efficiency, retaining 97% of its original power conversion efficiency value without PCBM clusters in the blend films even at elevated temperatures. There have been no previous reports on the thermal stability aspect of dibenzo[def, mno] chrysene-based polymer solar cells so far.