title: Synthesis of a new conjugated polymer composed of pyrene and bithiophene units for organic solar cells.
abstract: An alternating conjugated copolymer composed of pyrene and bithiophene units, poly(DHBT-alt-PYR) has been synthesized. The synthesized polymer was found to exhibit good solution processibility and thermal stability, losing less than 5% of their weight on heating to approximately 370 degrees C. The synthesized polymer showed its maximum absorption and peak PL emission at 401 and 548 nm, respectively. The optical band gap energy of the polymer was determined by absorption onset to be 2.64 eV. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the polymer was determined to be -5.48 and -2.84 eV by cyclic voltametry (CV) and the optical band gap. The polymer photovoltaic devices were fabricated with a typical sandwich structure of ITO/PEDOT:PSS/active layer/LiF/Al using poly(DHBT-alt-PYR) as an electron donor and C60-PCBM or C70-PCBM as electron acceptors. The open circuit voltage, short circuit current and fill factor of the device using C70-PCBM as an acceptor were 0.75 V, 3.80 mA/cm2 and 0.28, respectively, and the maximum power conversion efficiency of the device was 0.80%.
authors.affiliation: Department of Chemistry, and Chemistry Institute for Functional Materials, Pusan National University, Busan 609-735, Republic of Korea.
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Choong-Hwa
authors.initials: CH
authors.lastname: Jung
authors.forename: Jun
authors.initials: J
authors.lastname: Kang
authors.forename: Hee-Joon
authors.initials: HJ
authors.lastname: Kim
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Shin
authors.forename: Sung Cheol
authors.initials: SC
authors.lastname: Yoon
authors.forename: Sang-Jin
authors.initials: SJ
authors.lastname: Moon
authors.forename: Changjin
authors.initials: C
authors.lastname: Lee
authors.forename: Do-Hoon
authors.initials: DH
authors.lastname: Hwang