Molecular Engineering for Enhanced Charge Transfer in Thin-Film Photoanode

• DOI: 10.1021/acsami.7b08098
• Publication Date: 2017-09-15T17:42:05Z
• Authors: Jeong Soo Kim; Byung-Man Kim; Un-Young Kim; HyeonOh Shin; Jung Seung Nam; Deok-Ho Roh; Jun-Hyeok Park; Tae-Hyuk Kwon
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

We developed three types of dithieno[3,2-b;2′,3′-d]thiophene (DTT)-based organic sensitizers for high-performance thin photoactive TiO2 films and investigated the simple but powerful molecular engineering different bonding between triarylamine electron donor conjugated DTT π-bridge by introduction single, double, triple bonds. As a result, with only 1.3 μm transparent 2.5-μm scattering layers, triple-bond sensitizer (T-DAHTDTT) shows highest power conversion efficiency (η = 8.4%; VOC 0.73 V, JSC 15.4 mA·cm–2, FF 0.75) in an iodine electrolyte system under one solar illumination (AM 1.5, 1000 W·m–2), followed single-bond (S-DAHTDTT) 7.6%) double-bond (D-DAHTDTT) 6.4%). suggest that superior performance T-DAHTDTT comes from enhanced intramolecular charge transfer (ICT) induced bond. Consequently, exhibits most active photoelectron injection transport on film during operation, which leads to photocurrent density among systems studied. analyzed these correlations mainly terms efficiency, level photocharge storage, charge-transport kinetics. This study suggests bond increases dye-sensitized cell (DSC) enhancing not through improved ICT also evenly distributed surface coverage.