Indenothiophene-based asymmetric small molecules for organic solar cells

Abstract

The development of organic semiconductors is of key importance in order to improve the performance of organic solar cells (OSCs). Three indenothiophene (IT)-containing small molecules (IT3T, ITFBT and IT2FBT)were designed and synthesized for small molecule OSCs. The thermal, optical, and electrochemical properties of the molecules were investigated. The optical bandgaps of the three small molecules are ranged from 1.80 to 2.20 eV depending on different terminal groups flanked on the IT. We study the photovoltaic performances of the three molecules by fabricating OSCs with PC 71 BM as an electron acceptor. Among the three molecules, ITFBF exhibited the best power conversion efficiency of 4.57%with a high open circuit voltage (V OC ) of 0.98 V. We also briefly discuss structure-property guidelines for small molecules used for OSCs. The results demonstrate that IT-based small molecules are promising for small molecule OSCs with large V OC s.

High-performance asymmetric small molecular donor materials based on indenothiophene for solution-processed organic solar cells

“…These results suggested that both the SMs had good thermal stability. Compared with IT2FBT ( T d : 398 °C) [29] , IT(2FBT-T3Cz) 2 and IT(2FBT-TT3Cz) 2 presented higher T d . Therefore, incorporating the 3-carbozol terminal groups could improve the thermal stabilities of its resultant compounds.…”

“…The results demonstrated that the asymmetric indenothiophene can be an excellent donor core for organic semiconductors. Then Zheng's group also introduced IT to construct SMs donor materials for OSCs [29] . However, the maximum PCE of asymmetric IT-based device was only 4.57%.…”

Asymmetric triphenylamine–phenothiazine based small molecules with varying terminal acceptors for solution processed bulk-heterojunction organic solar cells

“…Huang et al reported four asymmetric molecules with varying terminal units and found that the increase in the donor-to-PC 71 BM dipolarity difference adversely influenced the donor-to-PC 71 BM phase-separation. 17 Besides this, asymmetric small molecules based on the building blocks diketopyrrolopyrrole, 23 benzothiadiazole, 24 indenothiophene, 18,25 squaraine, 26,27 and triphenylamine 28 have been reported for use in OSCs.…”