Chemical Physics Letters, Vol.663, 137-144, 2016
Efficient spirobifluorene-core electron-donor material for application in solution-processed organic solar cells
Efficient spirobifluorene-based organic small molecule (RTh-Sp-CF3) was synthesized in a simple manner via Suzuki coupling reaction containing an alkyl bithiophene as donor and 3,5-bis (trifluoromethyl) benzene as acceptor unit. The spirobifluorene-based small molecule was utilized as an electron-donor materials with well-known electron-acceptor material, phenyl-C-61-butyric acid methyl ester (PC61BM) in the solution-processed small molecule organic solar cells (SMOSCs). The incorporation of 3,5-bis (trifluoromethyl) benzene unit as electron-acceptor has significantly tuned the energy levels of small molecule and obtained the HOMO and LUMO energy levels of 5.35 eV and 3.92 eV, respectively. SMOSCs fabricated with RTh-Sp-CF3 accomplished an overall power conversion efficiency (PCE) of similar to 2.12% with short circuit current (Jsc) of similar to 8.42 mA/cm(2) and the open-circuit voltage (Voc) of similar to 0.66 V. The reasonable Jsc and Voc of devices might be attributed to the presence of strong electron-withdrawing fluorine units in RThSp-CF3, which resulted from the improved absorption and electrochemical properties. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:3,5-Bis (trifluoromethyl) benzene;Electrochemical properties;Spirobifluorene;Small molecule;Organic solar cells