Browsing by Subject "SMALL MOLECULES"

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    Synthesis and determination of fluorescence properties of new soluble diketopyrrolopyrrole type photosensitizers
    (ELSEVIER) Türkçen, S; Dinçalp, H; Saltan, GM
    Four organic small molecules bearing phenyl diketopyrrolopyrrole (DPP) unit as the main acceptor group and indole as the main thermal group with soluble units, coded as DPP3(a-b) and DPP4(a-b), were synthesized and their optical/electrochemical properties were investigated. Intense visible absorption bands around 480 nm were assigned to the DPP main core, as well as bands around 600 nm were attributed to the formation of charge-transfer complex between the electron-rich indole units and electron-withdrawing DPP core in chloroform solution. All of the compounds were found to be fluorescent in solution and on thin films with emission wavelengths between 500 and 700 nm. The fluorescence decay kinetic measurements of these dyes were also studied. The synthesized compounds have electrochemical energy band gaps from 2.15 to 2.28 eV. Then, the potential usage of the final products in bulk heterojunction solar cells (BFIJ-OSCs) were evaluated. (C) 2019 Elsevier B.V. All rights reserved.
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    Synthesis, characterization and optoelectronic properties of a new perylene diimide-benzimidazole type solar light harvesting dye
    (PERGAMON-ELSEVIER SCIENCE LTD) Dinçalp, H; Çimen, O; Ameri, T; Brabec, CJ; Içli, S
    A perylene diimide type small molecule (BI-PDI) has been synthesized through Suzuki coupling reaction between N,N'-bis(2,6-diisopropylphenyl)-1,7-dibromoperylene-3,4,9,10-tetracarboxylic diimide and 2-(2-hydroxyphenyl)-7-phenyl-1H-benzimidazole-4-boronic acid. BI-PDI small molecule has showed an absorption band between 350 and 750 nm on thin films. HOMO and LUMO energy levels of BI-PDI dye have been calculated to be about -5.92 eV and -3.82 eV, respectively. Solution-processed bulk heterojunction (BHJ) solar cells have been constructed using BI-PDI as donor and [6,6]-phenyl-C-61-butyric acid methyl ester (PC61BM) as acceptor or poly(3-hexylthiophene) (P3HT) as donor and BI-PDI as acceptor. The external quantum efficiencies (EQE) of the devices cover the most of the visible region between 400 and 700 nm for both configurations. Photovoltaic performances of BI-PDI-based organic solar cells are limited by the aggregation tendency of PDI structure and poor hole/electron mobilities of the active layer. (C) 2014 Elsevier B.V. All rights reserved.