Je, Hwan-Il Shin, Eul-Yong Lee, Keun Jun Ahn, Hyungju Park, Sungmin Im, Sang Hyuk Kim, Yun-Hi Son, Hae Jung Kwon, Soon-Ki 2024-01-19T17:32:24Z 2024-01-19T17:32:24Z 2021-09-04 2020-05-20 1944-8244 https://pubs.kist.re.kr/handle/201004/118612 Understanding the effects of the chemical structures of donor polymers on the photovoltaic properties of their corresponding organic photovoltaic (OPV) devices under various light-intensity conditions is important for improving the performance of these devices. We synthesized a series of copolymers based on poly[(2,6-(4,8-bis(5-(2-thioethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))] (PBDB-TS) and studied the effects of chlorine substitution of its thiophene-substituted benzodithiophene (BDT-Th) unit on its photovoltaic properties. Chlorination of the polymer resulted in a bulk heterojunction (BHJ) morphology optimized for efficient charge transport with suppressed leakage current and an increased open-circuit voltage of the OPV device; this optimization led to a remarkable enhancement of the OPV device's power conversion efficiency (PCE) not only under the condition of 1 sun illumination but also under a low light intensity mimicking indoor light; the PCE increased from 8.7% for PBDB-TS to similar to 13% for the chlorinated polymers, PBDB-TS-3Cl, and PBDB-TS-4Cl under the 1 sun illumination condition and from 5.3% for PBDB-TS to 21.7% for PBDB-TS-4Cl under 500 lx fluorescence illuminance. Interestingly, although the OPV PCEs under 1 sun illumination were independent of the position of chlorine substitution onto the polymer, PBDB-TS-4Cl exhibited better performance under simulated indoor light than its derivative PBDB-TS-3Cl. Our results demonstrate that efficient light absorption and charge-carrier generation play key roles in achieving high OPV efficiency under low-light-intensity conditions. English American Chemical Society SOLAR-CELLS GENERATION GAP Understanding the Performance of Organic Photovoltaics under Indoor and Outdoor Conditions: Effects of Chlorination of Donor Polymers Article 10.1021/acsami.0c02712 1 ACS Applied Materials & Interfaces, v.12, no.20, pp.23181 - 23189 ACS Applied Materials & Interfaces 12 20 23181 23189 scie scopus 000537394100080 2-s2.0-85085263812 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Science & Technology - Other Topics Materials Science Article SOLAR-CELLS GENERATION GAP organic photovoltaic benzodithiophene chlorine substitution bulk heterojunction indoor light