Tetrazine- and Pyridazine-based D-A’-A Derivatives for Dye-sensitized Solar Cells

• Main Authors: Hao-ju Chou, 周浩儒
• Other Authors: 林建村
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/80371687673895781490

碩士 === 國立中央大學 === 化學學系 === 103 === Sensitizers of D-A’-A type (D = donor; A’ = auxiliary acceptor; A = anchoring acceptor) have been widely investigated due to their good light-harvesting efficiency, low HOMO/LOMO gap, and excellent photostability. In this research, a series of new D-A’-A type sensitizers (HJ dyes) composed of a bis(n-hexylthienyl)tetrazine (TTz) or bis(n-hexylthienyl)pyridazine (TPz) core, an arylamine donor, such as triphenylamine, 9-(2-ethylhexyl)-9H-carbazole, N,N-diphenylthiophene-2-amine, and 4-(hexyloxy)-N- (4-(hexyloxy)phenyl)-N-phenylaniline as the electron donor entity and the 2-cyanoacetic acid as the acceptor as well as anchor have been synthesized for DSSC applications. These new dyes with tetrazine or pyridazine auxiliary acceptors have electronic absorption ranging from 300 to 600 nm, and the highest molar extinction coefficient reaching approximately 60,000 M-1cm-1. The HOMO (-5.89 to -5.43 eV) and LUMO (-3.54 to -3.16 eV) energy levels of the dyes calculated from the electrochemical and photophysical data assure favorable electron injection and regeneration. The light-to-electricity conversion efficiency of DSSC based on the HJ dyes is in a wide range of 0.35 to 6.25% under simulated AM 1.5 G illuminations. Low efficiencies of the cells can be attributed to the serious dye aggregation and the electron trapping effect, which is also supported by the theoretical calculation. Upon addition of CDCA as the co-adsorbent, the best performance has been slightly improved to 6.31%, which is of 76% of the N719-based standard DSSC.