A visible-near-infrared absorbing A–π2–D–π1–D–π2–A type dimeric-porphyrin donor for high-performance organic solar cells. Issue 48 (29th November 2017)

• Record Type: Journal Article
• Authors: Chen, Song; Yan, Lei; Xiao, Liangang; Gao, Ke; Tang, Wei; Wang, Cheng; Zhu, Chenhui; Wang, Xingzhu; Liu, Feng; Peng, Xiaobin; Wong, Wai-Kwok; Zhu, Xunjin
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 48(2018)
• Page Start: 25460
• Page End: 25468
• Publication Date: 2017-11-29
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7ta06217f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A new visible-near-infrared absorbing A–π2 –D–π1 –D–π2 –A type dimeric porphyrin donor is developed for high performance organic solar cells with an efficiency up to 8.29%. Abstract : Most of the currently available small molecule bulk heterojunction organic solar cells (BHJ OSCs) only utilize visible light and, to further increase the efficiency, the development of new organic materials that harvest near-infrared (NIR) light to produce an electric current is essential. Herein, a new A–π2 –D–π1 –D–π2 –A type dimeric porphyrin-cored small molecule (CS-DP ) is designed, synthesized and characterized. The use ofCS-DP with a narrow bandgap ( E g ) (1.22 eV) and the deep energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) affords the highest power conversion efficiency of 8.29% in BHJ OSCs with PC71 BM as an acceptor, corresponding to a short circuit current of 15.19 mA cm −2, an open circuit voltage of 0.796 V and a fill factor of 70% under AM 1.5G solar irradiation. The high device performance is attributed to the visible-near-infrared light-harvesting capability ofCS-DP, and the super low energy loss feature. The energy loss ( E loss ) lies between 0.43 and 0.51 eV in the system, which is related to the very small energy offset of the LUMOs between theCS-DP donor and PC71 BM (Δ E LUMO = 0.06 eV). The value of Δ E LUMO, which is considered as a driving force for the photoinduced charge separation, is much smaller than the empirical threshold of 0.3 eV, but would not be a limiting factor in the charge separation process. The results indicate that there may be room for further improving the PCE for low bandgap dimeric porphyrin systems.