| dc.description.abstract | Dye-sensitized solar cell (DSC) is a hot research topic because of its multicoloured, semi-transparent, flexible and low cost. A lot of studies are related to find new sensitizers nevertheless blue dye is relatively rare. In this thesis, we focus on the synthesis of blue dyes for DSC. Our previous study showed that BTI-3, BTI-5 and BTI-6 with benzothienoisoindigo (BTI) unit as an auxiliary acceptor (Aa) are blue-green in DMSO due to their λmax values are too long. To blue-shift the λmax of the dyes, BTI-4 is design by changing the position of acceptor part to be connected to the thiophene of BTI unit instead of connecting to the benzene. The λmax value of BTI-4 is smaller than that of BTI-3, but still in blue-green when dissolved in DMSO. BTI-7 and BTI-13 are prepared by inserting an additional phenyl unit between donor and Aa of BTI-3 and BTI-5, respectively. The λmax values of both BTI-7 and BTI-13 are smaller than those of BTI-3 and BTI-5. However, the color of BTI-7 and BTI-13 in DMSO is still blue-green. Finally we prepared BTI-15 and BTI-17 by using n-hexyl and bromide as donor instead of fluorene, respectively. The λmax value of BTI-15 is blue-shifted in DMSO but the color is still blue-green, nevertheless BTI-17 in DMSO is blue. BTI-4 and BTI-7 adsorbed on TiO2 film is green, BTI-13, BTI-15, and BTI-17 adsorbed on TiO2 film is red. These five dyes were used as sensitizers for DSC, BTI-13 has the highest conversion efficiency of 4.41%, due to its high molar absorption coefficient and large dye loading which leads to high surface coverage of when adsorbed on TiO2 film. | en_US |