Side chain engineering in DTBDT-based small molecules for efficient organic photovoltaics
- Hong, Jisu; Choi, Ji Young; Kim, Kyunghun; Lee, Nam-Suk; Li, Jiqiang; Park, Chan Eon; An, Tae Kyu; Kim, Yun-Hi; Kwon, Soon-Ki
- Issue Date
- ROYAL SOC CHEMISTRY
- NANOSCALE, v.11, no.29, pp.13845 - 13852
- Journal Title
- Start Page
- End Page
- A new small-molecule donor with a dithieno[2,3-d:2 ',3 '-d ']-benzo[1,2-b:4,5-b ']-dithiophene (DTBDT) core and both alkyl and alkylthio substituents is designed and synthesized to improve the miscibility between DTBDT-based small molecules and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM). The alkyl substituent on the 4-position and the alkylthio substituent on the 5-position of the substituted thiophene are expected to improve intermolecular interactions and prevent severe aggregation of the small molecules. The new small molecule, DTBDT-S-C8-TTR, exhibits a homogenous blend morphology with small domains and edge-on-oriented crystalline structures in blends with PC71BM, and give a maximum power conversion efficiency (PCE) of 8.43%. To recover the crystallinity of the DTBDT-S-C8-TTR small molecules weakened after being blended with PC71BM, a solvent vapor annealing (SVA) treatment is performed. The SVA-treated blend films reveal well-developed crystalline domains with interconnected fibrillar structures. This blend morphology allows efficient charge carrier transport in blends and leads to increased PCEs. The maximum PCE of 9.18% achieved using DTBDT-S-C8-TTR suggests that substituting both alkylthio and alkyl groups into DTBDT can yield small-molecule-based organic photovoltaics (OPVs) displaying improved photovoltaic performances.
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- 자연과학대학 > 화학과 > Journal Articles
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