1352642-35-3Relevant articles and documents
Replacing alkoxy groups with alkylthienyl groups: A feasible approach to improve the properties of photovoltaic polymers
Huo, Lijun,Zhang, Shaoqing,Guo, Xia,Xu, Feng,Li, Yongfang,Hou, Jianhui
, p. 9697 - 9702 (2011)
Another dimension: Two newly designed two-dimensional (2D) conjugated polymers, PBDTTT-E-T (see scheme; left) and PBDTTT-C-T, were prepared and their properties compared to those of the alkoxy-substituted analogues (right). PBDTTT-E-T and PBDTTT-C-T exhibited smaller band gaps, lower-energy HOMO levels, better thermal stabilities, and much better photovoltaic properties. Therefore, the 2D structures are feasible for the design of photovoltaic polymers. Copyright
Incorporation of pyrene units to improve hole mobility in conjugated polymers for organic solar cells
Kim, Ji-Hoon,Kim, Hee Un,Kang, In-Nam,Lee, Sang Kyu,Moon, Sang-Jin,Shin, Won Suk,Hwang, Do-Hoon
, p. 8628 - 8638 (2012)
Solution-processable semiconducting copolymers, poly[N-9′- heptadecanyl-2,7-carbazole-alt-5,5′-(4′,7′-di-2-thienyl- 2′,1′,3′-benzothiadiazole)] (PCDTBT) and poly[4,8-bis(2- ethylhexyl-2-thenyl)-benzo[1,2-b:4,5-b′]dithiophene-alt-5, 5′-(4′,7′-di-2-thienyl-2′,1′,3′- benzothiadiazole)] (PBDTDTBT), and their pyrene-containing terpolymers were synthesized using Suzuki or Stille coupling. Pyrene units were introduced to improve the charge-transporting abilities of the polymers. The resulting polymers were found to be soluble in common organic solvents and formed smooth and uniform spin-coated thin films. They also exhibited good thermal stability and lost 71BM/Ca/Al configuration fabricated using the pyrene-containing polymers had higher power conversion efficiencies than those using the corresponding parent polymers.
Molecular electron-acceptors based on benzodithiophene for organic photovoltaics
Jiang, Yue,Cabanetos, Clément,Allain, Magali,Liu, Ping,Roncali, Jean
, p. 2324 - 2328 (2015)
Two extended conjugated molecules potentially active as electron-acceptor materials for organic solar cells have been synthesized by grafting the electron-withdrawing dicyanovinyl (1) and p-cyano pyridyl (2) groups on the rigid and planar benzodithiophene (BDT) platform. UV-Vis spectroscopy shows that both compounds absorb in the visible region of the solar spectrum. Cyclic voltammetry indicates that only compound 1 presents a LUMO level comparable to that of fullerene C60. A preliminary evaluation of the potentialities of compound 1 as an electron-acceptor has been carried out on 'all-molecular' solution-processed bulk hetero-junction solar cells using a small triphenylamine-based system as the molecular donor. In spite of a high open-circuit voltage, the devices present a modest efficiency indicating that the light-harvesting properties and charge-mobility of the acceptor-molecules need further structural optimization.
Effect of fluorine content in thienothiophene-benzodithiophene copolymers on the morphology and performance of polymer solar cells
Liu, Peng,Zhang, Kai,Liu, Feng,Jin, Yaocheng,Liu, Shengjian,Russell, Thomas P.,Yip, Hin-Lap,Huang, Fei,Cao, Yong
, p. 3009 - 3017 (2014)
A new family of polythienothiophene-co-benzodithiophene copolymers with different amounts of fluorine decoration (PBFx) had been successfully synthesized. Detailed structure-property investigations covering physical properties, morphology, and solar cell performance with respect to the fluorine content in the polymers were performed by a series of structural characterization techniques. A PCE of 8.75% was obtained with the highest fluorinated polymer; the morphological trends, as well as the crystalline structure, were also investigated, shedding light on this important material modification.
A new organic far-red mechanofluorochromic compound derived from cyano-substituted diarylethene
Zhang, Xiqi,Ma, Zhiyong,Liu, Meiying,Zhang, Xiaoyong,Jia, Xinru,Wei, Yen
, p. 10552 - 10557 (2013)
A new cyano-substituted diarylethene derivative (R-NH2) with reversible far-red mechanofluorochromic property was synthesized and confirmed by standard spectroscopic methods. To the best of our knowledge, the 684 nm red-shifted wavelength of the ground R-NH2 is the longest wavelength that has appeared in the literature. The mechanofluorochromic mechanism was investigated by small and wide-angle X-ray scattering and was ascribed to the destruction of crystalline structure. More in-depth study by infrared spectra and time-resolved emission-decay behaviors showed that the changes of C-H out-of-plane bending vibrations in aryl group of the compound and the obvious increase of fluorescence lifetime might be the fundamental reasons. The synthetic strategy reported here can be extended to prepare more and more long-wavelength emission mechanofluorochromic materials, which can broaden the scope of application of such materials and for thoroughly understanding the mechanofluorochromic mechanism.
Synthesis and correlation between structure and photovoltaic performance of two-dimensional BDT-TPD polymers
Hong, Nam Jeong,Park, Hanok,Baek, Myoung-Jin,Lee, Soo-Hyoung,Jeong, Jo,Park, Jun Hui,Zong, Kyukwan
, p. 101 - 111 (2016)
Four BDT-TPD polymers (PA-PD) were synthesized by modifying the alkylthienyl chains on BDT, placing spacer group between BDT and TPD, and installing extended conjugated side chains on the BDT of the polymer to investigate the correlation between structure and photovoltaic performance for these polymers. The molecular weight of PA-PD polymers ranged from the highest (Mn = 80 kDa for PA) to the lowest (Mn = 7.9 kDa for PD), and their decomposition temperatures at 5% weight loss were in the range 401-435 °C. PA, PB, and PC showed similar UV-vis absorption spectra; however, PD showed much broader absorption spectrum in the entire UV-vis region, because of the extended conjugated side chains. The HOMO levels of the polymers were -5.72, -5.63, -5.48, and -5.61 eV for PA, PB, PC, and PD, respectively, indicating very low-lying HOMO energy levels. The bandgaps of these polymers were calculated and found to be in the range 1.85-1.88 eV. The theoretical calculations clearly show that the torsional angles between the alkylthienyl group and BDT unit of the simplified dimer correlated to the π-orbital delocalization, suggesting that the HOMO π-electrons of vertically aligned conjugated side chains do not delocalize well in the polymers such as PA, PB, and PC bearing high torsional angles. The optimized weight ratios of the polymer to PC61BM were determined to be 1:1, 1:1.5, and 1:1 for PA, PC, and PD, respectively, and the average PCEs of the devices were 5.36%, 4.62%, and 2.74% for PA, PC, and PD, respectively, after optimization with 1,8-diiodooctane (DIO). A relatively small amount of DIO as an additive was necessary to reach the optimal PCEs of the devices, and the device incorporating PC needed only 0.5% DIO to obtain the best PCE. The AFM study reveals that the blend films after adding DIO showed much smooth morphologies, and the blend film of PA exhibited more crystalline property, as shown by the XRD analysis.
Dithienopyrrole-benzodithiophene based donor materials for small molecular BHJSCs: Impact of side chain and annealing treatment on their photovoltaic properties
Busireddy, Manohar Reddy,Mantena, Venkata Niladri Raju,Chereddy, Narendra Reddy,Shanigaram, Balaiah,Kotamarthi, Bhanuprakash,Biswas, Subhayan,Sharma, Ganesh Datt,Vaidya, Jayathirtha Rao
, p. 312 - 325 (2016/07/21)
Two small molecular organic materials denoted as ICT1 and ICT2 with A-D1-D2-D1-A architecture have been synthesized and their thermal, photo-physical, electrochemical and photovoltaic properties are explored. Synthesized materials have n-butylrhodanine acceptor (A), dithienopyrrole (DTP) (D1) and benzodithiophene (BDT) (D2) (Alkoxy BDT and alkylthiophene BDT, respectively for ICT1 and ICT2) donor moieties. Both the materials have good solubility (up to 25 mg/mL) in most common organic solvents and have excellent thermal stability with the decomposition temperature (Td) as 348 and 382 °C, respectively for ICT1 and ICT2. Both ICT1 and ICT2 have broad and intense visible region absorption (molar excitation coefficient is 1.71 × 105 and 1.65 × 105 mol?1 cm?1, respectively for ICT1 and ICT2) and have suitable HOMO and LUMO energy levels for PC71BM acceptor. Bulk heterojunction solar cells with ITO/PEDOT:PSS/blend/Al structure are fabricated using these materials. The BHJSCs fabricated by spin cast of ICT1:PC71BM and ICT2:PC71BM (1:2 wt ratio) blend from chloroform showed power conversion efficiency (PCE) of 2.77% (Jsc = 6.84 mA/cm2, Voc = 0.92 V and FF = 0.44) and 3.27% (Jsc = 7.26 mA/cm2, Voc = 0.96 V and FF = 0.47), respectively. Annealing the active layer significantly improved the PCE of these BHJSCs to 5.12% (Jsc = 10.15 mA/cm2, Voc = 0.87 V and FF = 0.58) and 5.90% (Jsc = 10.68 mA/cm2, Voc = 0.92 V and FF = 0.60), respectively for ICT1 and ICT2 donors. The enhancement in the PCE is due to higher light harvesting ability of the active layer, better nanoscale morphology for efficient and balanced charge transport and effective exciton dissociation at the donor-acceptor interface.
