Abstract:
In a dye sensitized (DS) devices, the working principle is based on the excitation and injection of
electrons in the dye molecules. Due to the narrower spectral response of the dyes used as the sensitizer in
the DS devices, the efficiency of the DS solar cells remains low, which is a major drawback in
popularizing and commercializing DS solar cells. Therefore, the study of spectral response broadening
methods applicable to DS devices is vital. In general, when synthesizing novel dyes, long carbon chains
have been used to absorbed infrared radiation. In this study, cyanine dye molecules containing carbon
chains of different chain lengths were used to observe the variations in the spectral response of the DS
structures. Four cyanine dye derivatives, with different carbon ligands were investigated under the
configuration, n-D-p structure. TiO2 was used as the n-type semiconductor, and the CuSCN was used as
the p-type semiconductor, representing the n and p in the above configuration respectively. The device
sensitized with the dye containing the longest central polymethine chain have shown a red shift in the
spectral response threshold, extending up to ~900 nm. Additionally, the other dye molecules with shorter
carbon ligands have a lesser extension in the spectral response.
