| Dye Sensitized Nanocrystalline Photovoltaic Solar Cells are very prospective cleaning devices for the conversion of solar energy into electricity.They have simple structures,low coasts and could be manufactured easily.They are inert to the change of light intensity and environment temperature,having high incident photo-to-current conversion efficiency and light stability,and no pollutions.So they have attracted intense attentions since appeared in 1991.How to get higher inceident photon-to-current conversion efficiency and prolong the lifetime of the solar cells has being the focus.In order to sovel the backward of light stability and enlarge the optical absorption range of photosensitive dyes,3 kinds of phthalocyanines Zinc(â…¡) containing carboxyl group,tyrosine group and carbazole group.3 kinds of multi-nuclear phthalocyanine Zinc(â…¡) with 4-hydroxyphenyl-2,3-phthalazin-1-one(DHPZ) bridge and 2 kinds of phthalocyanine Lutetium(â…¢) were designed and prepared.Their UV-visible analyses,IR,Luminescence intensities analysis,the Incident Photon-to-current Conversion Efficiency(IPCE),the total efficiency were studied.It demonstrated that introducing hole-transporting group on the phthalocyanine ring,the electron density on the metal is increased.By irradiation of sunlight,the excited state molecule injectes electron into the conduction band of the nonostructured TiO2 and formes the oxidation state of Zn(â…¡) or Lu(â…¢) on the semi-conductor surface.Then the carbazole group can transfer electron to Zn(â…¡) or Lu(â…¢) and reduce it to the ground state of Zn or Lu, forming the carbazole radical and avoiding the backeward electron encountered with the oxidation states of dyes.The oxidation carbazole can obtain electron from electrolyte such as I-/I3- and the cycle complete with a result of preventing backward electron transfer efficiently. On the other hand,the optical absorption can be enlarged to 689 nm due to the conjugation between the carbazole and phthalocyanine ring.The 4-hydroxyphenyl-2,3-phthalazin-1-one(DHPZ) bridge has a strong conjugation between phthalocyanine rings and decrease the face-to face dimer or higher order aggregater. Thus the electric current density increases from 0.26 to 0.36 with the DHPZ brigde increasing. The rare earth metal Lutetium has seven redox statuses by irradiation of sunlight;in the result that there is a dual-transition at 688 nm and 713 nm.On the other hand,the optical absorption is enlarged to 713 nm due to the in-plane sandwich-type complexes.The total efficiency of photosensitive dye cells had been increased from 0.14 to 0.32 by the good maching with sunlight. |
