1320201-19-1Relevant articles and documents
Syntheses of pyrimidine-based polymers containing electron-withdrawing substituent with high open circuit voltage and applications for polymer solar cells
Kim, Juae,Young Shim, Joo,Lee, Jihoon,Yong Lee, Dal,Chae, Sangmin,Kim, Jinwoo,Kim, Il,Jung Kim, Hyo,Heum Park, Sung,Suh, Hongsuk
, p. 771 - 784 (2016)
Polymers using new electron-deficient units, 2-pyriminecarbonitrile and 2-fluoropyrimidine, were synthesized and utilized for the photovoltaics. Donor-acceptor (D-A) types of conjugated polymers (PBDTCN, PBDTTCN, PBDTF, and PBDTTF) containing 4,8-bis(2-octyldodecyloxy)benzo[1,2-b;3,4-b′]dithiophene (BDT) or 4,8-bis(5-(2-octyldodecyloxy)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene (BDTT) as electron rich unit and 2-pyriminecarbonitrile or 2-fluoropyrimidine as electron deficient unit were synthesized. We designed pyrimidine derivatives in which strong electron-withdrawing group (C-N or fluorine) was introduced to the C2 position for the generation of strong electron-deficient property. By the combination with the electron-rich unit, the pyrimidines will provide low band gap polymers with low highest occupied molecular orbital (HOMO) energy levels for higher open-circuit voltages (VOC). For the syntheses of the polymers, the electron-rich and the electron-deficient units were combined by Stille coupling reaction with Pd(0)-catalyst. Absorption spectra of the thin films of PBDTTCN and PBDTTF with BDTT unit show shift to a longer wavelength region than PBDTCN and PBDTF with BDT unit. Four synthesized polymers provided low electrochemical bandgaps of 1.56 to 1.96 eV and deep HOMO energy levels between -5.67 and -5.14 eV.
Synthesis and characterization of two fluorenone-based conjugated polymers and their application in solar cells and thin film transistors
Lim, Chia Juan,Lei, Yanlian,Wu, Bo,Li, Lu,Liu, Xuyao,Lu, Yong,Zhu, Furong,Ong, Beng S.,Hu, Xiao,Ng, Siu-Choon
, p. 1430 - 1434 (2016/03/12)
Two new fluorenone-based conjugated polymers, F1 and F2, were synthesized via the Stille cross-coupling polymerization. Spectral measurements showed that both polymers had optical band gaps of 1.99 eV and 1.89 eV, respectively, calculated based on the film onset absorption edge. Cyclic voltammetric studies gave HOMO/LUMO energy levels of -5.18 eV/-3.19 eV and -5.40 eV/-3.51 eV, respectively, and the polymers were thermally stable at temperatures over 300 °C. Organic field-effect transistor and bulk-heterojunction solar cell performance characteristics of both polymers as p-type semiconductors were evaluated.
Syntheses and solar cell applications of conjugated copolymers containing tetrafluorophenylene units
Kim, Jinwoo,Kim, Taehyo,Kim, Nam Hee,Kim, Juae,Shim, Joo Young,Kim, Il,Chun, Ho Hwan,Kim, Jin Young,Jin, Jong Sung,Kim, Jong Pil,Jeong, Euh Duck,Suh, Hongsuk
, p. 113 - 121 (2016/01/15)
Novel conjugated copolymers containing tetrafluorophenylene unit have been synthesized and evaluated in bulk heterojunction solar cell. The tetrafluorophenylene unit, as the strong electron deficient moeity, has been applied for the syntheses of donor-acceptor type copolymers with a narrow-band-gap for bulk heterojunction solar cells. DTBT, tetrafluorophenylene and four types of BDT derivatives as the electron rich units were incorporated using Stille polymerization to generate PE-BDTF, PO-BDTF, PE-BDTTF and PO-BDTTF. The introduction of even 1% of tetrafluorophenylene unit substituting DTBT of BDTDTBT type of polymers results in significant decrease of the band gap of the polymers. The device with PO-BDTF:PC71BM (1:1) showed an open-circuit voltage (VOC) of 0.75 V, a short circuit current (JSC) of 11.80 mA/cm2, and a fill factor (FF) of 0.59, which yields PCE of 5.22%.
Syntheses and properties of copolymers with N-alkyl-2,2′-bithiophene-3,3′-dicarboximide unit for polymer solar cells
Kim, Juae,Kim, Shin Hyun,Kim, Taehyo,Shim, Joo Young,Park, Dongkyung,Kim, Jinwoo,Kim, Il,Kim, Jin Young,Suh, Hongsuk
, p. 2238 - 2246 (2015/09/22)
We report new random copolymers using the electron-deficient unit N-alkyl-2,2′-bithiophene-3,3′-dicarboximide (BTI) for organic solar cells. For absorption over a broader range of the solar spectrum, push-pull types of conjugated polymers PBTIBDT-3, PBTIBDT-5, and PBTIBDT-7, containing 4,8-bis(2-octyldodecyloxy) benzo[1,2-b;3,4-b']dithiophene (BDT) as electron-pushing unit and BTI as electron-pulling unit, were synthesized. The polymers were synthesized by coupling electron-pushing and electron-pulling units by Stille polymerization with Pd(0) catalyst. The incorporation of more BTI units induced more red shift of the absorption spectra of the polymer thin films. The device comprising PBTIBDT-5 and PC71 BM (1:1) showed VOC = 0.76 V, JSC = 3.28 mA/cm2, and fill factor (FF) = 0.51, giving a power conversion efficiency of 1.26%.
Polymer solar cells based on quinoxaline and dialkylthienyl substituted benzodithiophene with enhanced open circuit voltage
Song, Kwan Wook,Lee, Tae Ho,Ko, Eui Jin,Back, Kyung Hun,Moon, Doo Kyung
, p. 1028 - 1036 (2014/03/21)
A poly[benzodithiophene-alt-di-2-thienyl-quinoxaline] series (PBDTDPQ-EH, PBDTDPQ-OD, and PBDTDPQ-HDT) was synthesized via Stille coupling. Deep highest occupied molecular orbital (HOMO) levels were achieved by the introduction of 2-decyl-4-hexyl-thiophen-yl (HDT) side chains. The introduction of the various side chains increased the molecular weight of the polymers, and the polymers dissolved well in common organic solvents at room temperature. The HOMO energy level (-5.20 to -5.49 eV) decreased because of the 2D conjugated structure. X-ray diffraction analysis showed that PBDTDPQ-OD had a slightly edge-on structure. In the case of PBDTDPQ-HDT, however, the structure was amorphous due to the thiophene side chain, and the extent of π stacking increased. After fabricating bulk-heterojunction-type polymer solar cells, the OPV characteristics were evaluated. The values of open-circuit voltage (V oc), short-circuit current (Jsc), fill factor, and power conversion efficiency (PCE) were 0.88 V, 7.9 mA cm-2, 45.4%, and 3.2%, respectively.
Synthesis and photovoltaic properties of new conjugated polymers based on di(2-furyl)thiazolo[5,4-d]thiazole and benzo[1,2-b:4,5-b′]dithiophene
Hu, Chao,Wu, Zhongwei,Cao, Kangli,Sun, Baoquan,Zhang, Qing
, p. 1098 - 1105 (2013/03/28)
Di(2-furyl)thiazolo[5,4-d]thiazole (DFTT) has been studied as building block for conjugated polymers. New polymer PBDTODFTT and PBDTTDFTT based on DFTT and two different benzo[1,2-b:4,5-b′]dithiophene (BDT) repeating units have been synthesized and applied as donors in bulk hetero-junction polymer solar cell devices. The polymer PBDTODFTT and PBDTTDFTT have optical bandgap of 2.00 eV and 1.98 eV, and show HOMO energy level of -5.46 eV and -5.36 eV, respectively. The solar cell devices based on PBDTTDFTT:PC61BM blend as active layers have achieved an open-circuit voltage of 0.83 V and a power conversion efficiency of 3.06% under the illumination of AM 1.5 G (100 mW/cm2).
Effects of π-conjugated bridges on photovoltaic properties of donor-π-acceptor conjugated copolymers
Wang, Xiaochen,Sun, Yeping,Chen, Song,Guo, Xia,Zhang, Maojie,Li, Xiaoyu,Li, Yongfang,Wang, Haiqiao
experimental part, p. 1208 - 1216 (2012/06/30)
A series of conjugated donor (D)-π-acceptor (A) copolymers, P(BDT-F-BT), P(BDT-T-BT), and P(BDT-TT-BT), based on benzodithiophene (BDT) donor unit and benzothiadiazole (BT) acceptor unit with different π-bridges, were designed and synthesized via a Pd-catalyzed Stille-coupling method. The π-bridges between the BDT donor unit and BT acceptor unit are furan (F) in P(BDT-F-BT), thiophene (T) in P(BDT-T-BT) and thieno[3,2-b]thiophene (TT) in P(BDT-TT-BT). It was found that the π-bridges significantly affect the molecular architecture and optoelectronic properties of the copolymers. With the π-bridge varied from furan to thiophene, then to thieno[3,2-b]thiophene, the shape of the molecular chains changed from z-shaped to almost straight line gradually. Band gaps of P(BDT-F-BT), P(BDT-T-BT) and P(BDT-TT-BT) were tuned from 1.96 to 1.82 to 1.78 eV with HOMO levels up-shifted from -5.44 to -5.35 to -5.21 eV, respectively. Bulk heterojunction solar cells with the polymers as donor and PC71BM as acceptor demonstrated power conversion efficiency varied from 2.81% for P(BDT-F-BT) to 3.72% for P(BDT-T-BT) and to 4.93% for P(BDT-TT-BT). Compared to furan and thiophene, thieno[3,2-b]thiophene π-bridge in the copolymers shows superior photovoltaic performance. The results indicate that the photovoltaic performance of some high efficiency D-A copolymers reported in literatures could be improved further by inserting suitable π-bridges.
Synthesis and characterization of thieno[3,4-b]thiophene-based copolymers bearing 4-substituted phenyl ester pendants: Facile fine-tuning of homo energy levels
Yamamoto, Tomoyuki,Ikai, Tomoyuki,Kuzuba, Mitsuhiro,Kuwabara, Takayuki,Maeda, Katsuhiro,Takahashi, Kohshin,Kanoh, Shigeyoshi
scheme or table, p. 6659 - 6662 (2012/03/26)
A study was conducted to design and synthesize PTB-based polymers bearing 4-substituted phenyl esters in place of the alkyl esters as the pendants of the thieno[3,4-b]thiophene (TT) unit. It was found that their highest occupied molecular orbital (HOMO) energy levels were readily fine-tuned by changing the substituents on the phenyl groups. Four novel TT monomers bearing various phenyl ester groups (TT1-TT4) were easily prepared in one pot from commercially available phenol derivatives and the key precursor compound, 4,6-dibromothieno[3,4-b]thiophene-2-carboxylic acid, which was synthesized by modified literature procedures. The molecular weights of the obtained polymers were determined by size-exclusion chromatography (SEC) in tetrahydrofuran (THF). The thermal stability of these polymers was investigated by thermal gravimetric analysis (TGA) under a nitrogen atmosphere. The results show that all polymers have good thermal stability with 5% weight loss temperatures (Td) above 300 °C, which is adequate for application in PSC devices.
