18229-38-4Relevant academic research and scientific papers
Synthesis and photovoltaic properties of copolymers with a fluoro quinoxaline unit
Song, Suhee,Kim, Seungmin,Kim, Wonjun,Park, Seong Soo,Park, Sung Heum,Jin, Youngeup
, p. 821 - 830 (2018)
Two novel accepter units, namely, difluoroquinoxaline and monofluoroquinoxaline, were prepared and used for the synthesis of the conjugated polymers containing electron donor–acceptor pairs for use in organic photovoltaics. The introduction of a fluorine atom into the quinoxaline moiety resulted in polymers with lowered highest occupied molecular orbital (HOMO) energy levels; this increased the open circuit voltage of the devices based on the synthesized polymers. The conjugated polymers containing difluoroquinoxaline and monofluoroquinoxaline, namely, thiophene and benzodithiophene, were synthesized using the Stille polymerization reaction to produce PEHBQxF2, PEHBQxF1, PEHBDTQxF2, and PEHBDTQxF1. The HOMO energy levels of PEHBQxF2, PEHBQxF1, PEHBDTQxF2, and PEHBDTQxF1 were determined to be ?5.66, ?5.52, ?5.54, and ?5.39 eV, respectively. The device with PEHBDTQxF2/PC71BM (1:2, w/w) and containing diiodooctane (3 vol %) exhibited the best photovoltaic performance, with its VOC being 0.79 V, JSC being 10.44 mA/cm2, FF being 68%, and PCE being 5.58%.
Photovoltaic polymers based on difluoroqinoxaline units with deep HOMO levels
Song, Suhee,Keum, Sangha,Lee, Ji-Hyun,Lee, Jihoon,Kim, Seungmin,Park, Seong Soo,Kim, Jin Young,Park, Sung Heum,Jin, Youngeup
, p. 1489 - 1497 (2018)
We report the synthesis of low bandgap polymers with a difluoroquinoxaline unit by Stille polymerization for use in polymer solar cells (PSCs). A new series of copolymers with 2,3-didodecyl-6,7-difluoro quinoxaline as the electron-deficient unit and alkyloxybenzo[1,2-b:4,5-b′]dithiophene and thiophene as the electron-rich unit were synthesized. The photovoltaic properties of the devices based on the synthesized polymers revealed that the fluorine atoms at the quinoxaline units aid in decreasing the highest occupied molecular orbital (HOMO) energy levels; this in turn increased the open circuit voltage of the devices. The polymers with long alkyl chains exhibited good solubility that increased their molecular weight, but the power conversion efficiency was low. Efficient polymer solar cells were fabricated by blending the synthesized copolymers with PC71BM, and the PCE increased up to 5.11% under 100 mW cm?2 AM 1.5 illumination. These results demonstrate that the importance of having a control polymer to be synthesized and characterized side by side with the fluorine analogues.
Thieno[3,4-b]pyrazines: Synthesis, structure, and reactivity
Kenning, Don D.,Mitchell, Kari A.,Calhoun, Tessa R.,Funfar, Melanie R.,Sattler, Daniel J.,Rasmussen, Seth C.
, p. 9073 - 9076 (2007/10/03)
A general synthetic route has been developed for the efficient preparation of 2,3-disubstituted thieno[3,4-b]-pyrazines. These methods eliminate problems in the preparation of the precursor 3,4-diaminothiophene and utilize α-diones prepared through the reaction of the appropriate organocuprates with oxalyl chloride. This combination allows the convenient preparation of thieno[3,4-b]pyrazine and its 2,3-disubstituted analogues (where substituent = methyl, hexyl, octyl, decyl, dodecyl, and phenyl) in high yield. Characterization of the structure and reactivity of this class of compounds is also described, including the results of structural, electrochemical, and pKa studies.
