| dc.description.abstract | The environmental problems related to the fossil energy is one of the energy issues causing great attention. Alternative energy sources becomes one of the important subject people are searching for. Solar cell, which converts light energy into electricity, is the most promising technology amongst the renewable energy. Dye-sensitized solar cell, DSSC, is considered as an alternative to the conventional solar cells due to its transparence, flexibility, high conversion efficiency, and low cost. Ruthenium complexes exhibit relatively high DSSC performance. However, ruthenium complexes did not efficiently absorb the photons in the Far-Red (FR)/Near-Infrared (NIR) region. To improve the performances of DSSCs, it would be essential to develop FR/NIR sensitizer. In this thesis, we designed and synthesized two new donor-π-conjugated-acceptor (D-π-A) unsymmetrical squaraine dyes, WCH-SQ10 and WCH-SQ11. These two squaraine dyes, have a triphenylamine as an electron donor, 3,4-Ethylenedioxythiophene as a conjugate moiety, and quinoline with COOH as an acceptor. WCH-SQ10 showed absorption maximum (λmax) centered at 686 nm with a molar absorption coefficient (ε) of 92376 M-1 cm-1 and λmax of WCH-SQ11 centerd at 673 nm with a ε of 87154 M-1 cm-1. The full width at half-maximum (FWHM) are 122 nm and 120 nm for WCH-SQ10 and WCH-SQ11, respectively. The overall conversion efficiency (ŋ) for WCH-SQ10 was 1.77 % (Jsc = 9.25 mA/cm2，Voc = 374 mV，FF = 0.51), for WCH-SQ11 was 1.96 % (Jsc = 9.06 mA/cm2，Voc = 391 mV，FF = 0.55) under the illumination of AM (air mass) 1.5 global simulated sunlight (100 mW/cm2). Incident photon-to-current conversion efficiency (IPCE) spectra of the devices sensitized by WCH-SQ10 and WCH-SQ11, reveal the efficiency at wavelength from 800 nm to 1100 nm. The results suggest that squaraine dye is a promising FR/NIR sensitizer.
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