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 °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. image