Design, Synthesis And Applications Of Aromatic Amine Dyes

Dye-sensitized solar cells have been attracting many researchers'attention in the field of photovoltaic conversation of solar energy because of their simple preparation and low cost. A photosensitive dye as the core of such a cell, it harvestes the sunlight to form excited state and then the electon is transferred to the external circuit, simultaneously, the dye is regenerated by the iodide/triiodide couple as a redox system in the electrolyte. Until now, the performances of Ru-complexes have been greatest, however, the use of precious mental ruthenium brings about the high cost and the separation and purification of the dye is also very difficult. So, organic dyes are increasingly applied in DSSCs by virtue of their high molar extinction coefficient, easy preparation and purification, low cost, as well as their rich structures.Under the above research background, in this thesis, firstly, A1 and A2 have been designed, synthesized and applied to DSCs with 2-(N,N-dicyclohexyl)thiophenine as the electron donor, thiophene asπ-conjugated bridge,2-cyanoacrylic acid and rhodanine acetic acid respectively as the electron acceptor. The energy conversion efficiency of a DSC based on A1 is 3.11% and which is only 0.5% when a DSC based on A2, which indicates that the LUMO level of A2 is too close to the TiO2 conduction band to obtain a insufficient driving force. Whatever, thiophenines can be adopted to sensitizers as an electron donor.Secondly, B1, B2, C1 and C2 have been designed and synthesized with triphenylamine as the electron donor, 2-cyanoacrylic acid as the electron acceptor and differentπ-conjugated bridges. The electron acceptor of B1 and B2 are ethyl cyanoacetate and t-butyl cyanoacetate, respectively, although they are not carboxylic acid, they enlarge the spectral response and possess obvious charge separation according spectroscopy and theoretical calculation because of their special connection type in molecular. When C1 and C2 are applied to DSCs, the energy conversion efficiency of a DSC based on C1 and DCA, which is due to the better coplanarity compared to C2, is 5.80% and which is 6.21% when a DSC based on C2 under the same conditions, however, the Voc and FF of a DSC based on C1 displays higher than that of C2. More importantly, the IPCE curve of a DSC based on C1 becomes more enlarger and higher when increases the thickness of TiO2 film and which becomes opposite when a DSC based on C2, which implies that there is still some room for the development of C1.Lastly, D1 and D2 have been designed and synthesized with triphenylamine as the electron donor, terephthalonitrile as the electron acceptor, thiazole and thiophene respectively asπ-conjugated bridges. The structures of the dyes have been characterized by high resolution mass spectrometer (HRMS), proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR) technology. According the single-photon and two-photon performance test, compared to reference compound D, D1 and D2 in the single-photon absorption spectra have some red shift, and they have large two-photon absorption cross section(σ),1447 GM and 1329 GM which are larger than that of D which is 1016 GM. Of course, largeσis benefit for further application. And all of these are confirmed by electrochemical tests and theoretical calculations.