Efficient Cathode Buffer Material Based on Dibenzothiophene-,-dioxide for Both Conventional and Inverted Organic Solar Cells.
Guiting Chen, Hongli Wu, Chuang Feng, Zhikai Deng, Zhuyang Li, Mingxin Nie, Baitian He, Hongqing Hao, Xin Li, Zhicai He
Author Information
Guiting Chen: School of Chemistry and Environment, Jiaying University, Meizhou 514015, China. ORCID
Hongli Wu: Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
Chuang Feng: Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
Zhikai Deng: School of Chemistry and Environment, Jiaying University, Meizhou 514015, China.
Zhuyang Li: School of Chemistry and Environment, Jiaying University, Meizhou 514015, China.
Mingxin Nie: School of Chemistry and Environment, Jiaying University, Meizhou 514015, China.
Baitian He: School of Chemistry and Environment, Jiaying University, Meizhou 514015, China.
Hongqing Hao: School of Chemistry and Environment, Jiaying University, Meizhou 514015, China.
Xin Li: School of Chemistry and Environment, Jiaying University, Meizhou 514015, China.
Zhicai He: Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China. ORCID
A novel conjugated molecule (PBSON) based on a main chain composed of bis(dibenzothiophene-,-dioxide) fused cyclopentadiene and side chains containing amino groups is presented as an efficient cathode buffer material (CBM) for organic solar cells (OSCs). PBSON showed a deep highest occupied molecular orbital (HOMO) energy level of -6.01 eV, which was beneficial for building hole-blocking layers at the cathodes of OSCs. The energy bandgap of PBSON reached 3.17 eV, implying high transmittance to visible and near-infrared light, which meant PBSON should be suitable for the applications to most inverted OSCs. The scanning Kelvin probe microscopy measurement and theoretical calculation on the PBSON/cathode interfacial interaction proved the excellent work function-regulating abilities of PBSON for various cathodes, suggesting that PBSON could promote the formation of Ohmic contacts at the cathodes and thus improve the transport and collection of electron carriers for OSCs. The characterization of electron-only devices demonstrated the good electron-transporting performance of PBSON at the cathodes. In the conventional OSCs, it was hinted that PBSON might restrain the infiltrations of evaporated cathode atoms into the active films, consequently reducing the reverse leakage currents. As a result, PBSON was able to boost the power conversion efficiencies (PCEs) by 58.2 and 56.4% for both conventional and inverted OSCs of the typical PTB7:PCBM system, respectively, as compared to the unadorned devices. In terms of the classical PTB7-Th:PCBM system, substantial increases in PCEs could also be found with PBSON interlayers, which were 54.7 and 59.8% for the conventional device and inverted device, respectively. Therefore, PBSON is a kind of promising CBM for realizing both conventional and inverted OSCs of high performance.
References
Adv Mater. 2011 Oct 25;23(40):4636-43
[PMID: 21905131]
Angew Chem Int Ed Engl. 2021 Aug 23;60(35):19053-19057
[PMID: 34160863]
