1391764-83-2Relevant articles and documents
Conjugated and nonconjugated substitution effect on photovoltaic properties of benzodifuran-based photovoltaic polymers
Huo, Lijun,Ye, Long,Wu, Yue,Li, Zhaojun,Guo, Xia,Zhang, Maojie,Zhang, Shaoqing,Hou, Jianhui
, p. 6923 - 6929 (2012)
In order to investigate the influence of two-dimensional (2D) conjugated structure on photovoltaic properties of benzo[1,2-b:4,5-b']difuran (BDF)-based polymers, two low band gap photovoltaic polymers, named PBDFTT-CF-O and PBDFTT-CF-T, were designed and synthesized. These two polymers have the same backbones and different side groups. Although these two polymers show similar optical band gaps (ca. 1.5 eV), the polymer with alkylthienyl side groups, PBDFTT-CF-T, exhibits stronger absorption in long wavelength direction than the polymer with alkoxyl side groups, PBDFTT-CF-O. Meanwhile, PBDFTT-CF-T exhibits a HOMO level of -5.21 eV, which is 0.23 eV lower than that of PBDFTT-CF-O due to weaker electron-donating ability of alkylthienyl side groups than that of aloxyl side groups. The hole mobility of the blend of PBDFTT-CF-T/PC71BM (1:1.5, w/w) is 0.128 cm2 V-1 s-1, which is 1 order of magnitude higher than that of the blend of PBDFTT-CF-O/PC 71BM. Density functional theory (DFT) model shows thiophene pendants on dithienyl-BDF are more coplanar than it on dithienyl-BDT. These results indicate that the 2D-conjugated structure is helpful for molecular structure design of the BDF-based polymers in enhancing the intermolecular π-π stacking and improving charge transport property. Furthermore, the photovoltaic devices based on these two polymers show similar short circuit density and fill factor values, while the open circuit voltage of the PBDFTT-CF-T-based device is 0.78 V, which is 0.15 V higher than that of the PBDFTT-CF-O-based device. Therefore, the efficiencies of the devices based PBDFTT-CF-T/PC71BM and PBDFTT-CF-O/PC71BM are 6.26% and 5.22%, respectively. The results in this work demonstrate that the weak electron-donating ability of alkylthienyl side groups can be seen as an effective strategy to improve photovoltaic properties of the BDF-based polymers and the 2D-conjugated molecular structure is favorable to improve hole mobility.
Two-dimensional benzo[1,2-: B:4,5- b ′]difuran-based wide bandgap conjugated polymers for efficient fullerene-free polymer solar cells
Gao, Yueyue,Wang, Zhen,Zhang, Jianqi,Zhang, Hong,Lu, Kun,Guo, Fengyun,Yang, Yulin,Zhao, Liancheng,Wei, Zhixiang,Zhang, Yong
, p. 4023 - 4031 (2018)
Wide bandgap conjugated polymers are important for providing complementary absorption with the state-of-the-art narrow bandgap nonfullerene electron acceptors to maximise the utilization of solar photons. In this work, two wide bandgap two-dimensional conjugated polymers, PBDFT-Bz and PBDFF-Bz, based on benzo[1,2-b:4,5-b′]difuran building block were designed and synthesized. The optical bandgaps of PBDFT-Bz and PBDFF-Bz were found to be 1.90 eV and 1.85 eV, respectively. PBDFF-Bz with 2-ethylhexylfuryl side chains possesses the lower HOMO energy level and shows denser π-π stacking compared to PBDFT-Bz with 2-ethylhexylthienyl side chains. The fullerene-free PBDFF-Bz:ITIC-based polymer solar cell (PSC) showed a PCE of 9.46% with a Jsc of 15.02 mA cm-2, a Voc of 0.94 V and a FF of 67%; by using m-ITIC as an electron acceptor, the PCE was further improved to 10.28% with an enhanced Jsc of 16.57 mA cm-2, a Voc of 0.94 V and a FF of 66%. Under the same condition, the PBDFT-Bz:m-ITIC device gave a PCE of 9.84% with a Jsc of 16.63 mA cm-2, a Voc of 0.85 V and a FF of 70%. In addition, it is exciting that the PBDFF-Bz based devices show a small energy loss (Eloss) of 0.63 eV, while the PBDFT-Bz based devices show an Eloss of 0.72 eV. These results are among the best for fullerene-free devices with BDF-based polymers, and demonstrate that BDF is a very promising candidate for highly efficient polymer solar cells.
Two-dimensional conjugated benzodifuran organic micro-molecular photovoltaic material, and preparation method and application thereof
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Paragraph 0064-0069; 0085-0090; 0106-0111; 0127-0132; 0148, (2017/08/29)
The invention discloses a two-dimensional conjugated BDF organic micro-molecular photovoltaic material, and a preparation method and an application thereof. Two-dimensional conjugated BDF organic micro-molecules with the structure represented by formula (I) are obtained by connecting a thiophene conjugate side chain-containing benzo[1,2-b;3,4-b]difuran (BDF) unit with another aryl heterocycle through a Stille coupling technology. The organic micro-molecular photovoltaic material has wide visible region absorption, suitable HOMO and LUMO energy levels and narrow band gap. Organic solar cells are produced by using the organic molecules as an electron donor and PC61BM as an electron receptor, the maximum energy conversion efficiency of the organic solar cells reaches up to 3.7%, and the organic solar cells have a good photoelectric conversion efficiency.