Browsing by Subject "Organic photovoltaics"

Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    Improvement of intramolecular charge transfer within a donor-acceptor blend by doping novel synthesized benzothiadiazole small molecules in solid state
    (Elsevier B.V., 2014) Dinçalp H.; Murat G.; Içli S.
    Three electron-deficient small molecules based on 2,1,3-benzothiadiazole (BTD) units namely, 4,7-bis(3-methoxyphenyl)-2,1,3-benzothiadiazole (BT1), (3-{7-[3-(dimethylamino)phenyl]-2,1,3-benzothiadiazole-4-yl}phenyl) dimethylamine (BT2) and 3,3′-(2,1,3-benzothiadiazole-4,7-dyl)dianiline (BT3) were synthesized and their photophysical properties were investigated systematically to understand their potential usage in ternary organic solar cells (OSCs) as additive material to enhance the cell efficiency. All these molecules show broad absorption bands in 350-750 nm on glass substrate and their optical band gaps were calculated to be around 2.50-2.80 eV. BTD fluorescence dynamics were measured in polymer:BT1:fullerene blends with varying emission wavelengths of active layer. Fluorescence emission and time resolved measurements indicated photoinduced energy shift from BT1 dye to fullerene and also from polymer to BT1 dye upon excitation of the active layer. © 2014 Elsevier B.V. All rights reserved.
  • No Thumbnail Available
    Item
    Functionalized bay-substituted perylene diimide additives for inverted organic photovoltaic devices based on P3HT/PCBM
    (National Institute of Optoelectronics, 2015) Dinçalp H.; Çmen O.; Murat Saltan G.; Çl S.
    The photovoltaic performances of inverted organic solar cells including P3HT:PCBM active layer with perylene diimides (PDIs) substituted with different subunits at bay positions of perylene ring were investigated. The improvement of photoluminescence intensity for P3HT:PCBM blend was achieved by the increase of PDI1 additive amount from 6.6 to 10 wt%. In P3HT:PDI1:PCBM ternary blend, preliminary results obtained from cell measurements indicated that PDI1 dopant has improved the cell efficiency by 38% compared to the control cell. Carrier mobility studies revealed that electron or hole mobility capacities of the perylene additives in ternary blends gave a more detailed explanation for efficiencies both binary and ternary systems.
  • No Thumbnail Available
    Item
    Synthesis and photophysical characterization of isoindigo building blocks as molecular acceptors for organic photovoltaics
    (Elsevier B.V., 2018) Dinçalp H.; Saltan G.M.; Zafer C.; Mutlu A.
    Five isoindigo-based donor-acceptor-donor (D-A-D) type small molecules have been synthesized in order to investigate their intramolecular charge transfer characteristics. UV–vis absorption of these dyes exhibits a wide absorption band ranging from 300 to 650 nm with two distinct bands, giving the narrow bandgaps between 1.72 and 1.85 eV. Taking into account their HOMO-LUMO energy levels and bandgaps, isoindigo dyes have been used in the active layer of organic solar cell (OSC) devices. When these small molecule semiconductors were used as acceptors with the donor poly(3-hexylthiophene-2,5-diyl (P3HT) polymer in the inverted OSC devices, the highest power conversion efficiency (PCE) was obtained as 0.10% for pyrene-substituted isoindigo derivative. © 2018 Elsevier B.V.
  • No Thumbnail Available
    Item
    Bromo-substituted cibalackrot backbone, a versatile donor or acceptor main core for organic optoelectronic devices
    (Elsevier B.V., 2018) Dinçalp H.; Saltan G.M.; Zafer C.; Kıymaz D.A.
    Cibalackrot (Ci-I), one of the latest highly conjugated compound possessing bis-lactam structure, was investigated with respect to their brominated derivatives in order to determine their suitable substitution points for the syntheses of new class of small molecules for optoelectronic devices. 7,14-Bis(4-bromophenyl) (Ci-II) and 3,10-dibromo (Ci-III) derivatives of cibalackrot possess moderately narrow band gaps of 2.15 and 2.09 eV, respectively. Notably, Ci-III dye exhibits more red-shifted ultraviolet–visible (UV–vis) absorption and fluorescence emission spectra as compared to that of Ci-II dye because Ci-III shows more prominent intramolecular charge transfer (ICT) complex than that of Ci-II dye. Electron mobilities of the order of 7.0 × 10−4 cm2/V and 3.1 × 10−4 cm2/V were measured using Ci-II and Ci-III as active layer, respectively. Charge transfer properties of the molecules were investigated in bulk heterojunction device configuration wherein Ci-III showed p-type behavior against n-type PCBM in photovoltaic device. Photovoltaic performance of Ci-III dye which was used as donor component is 20 times higher than that of the device in which this dye was used as acceptor. © 2018 Elsevier B.V.