Synthesis And Property Study Of Photoinduced Electron Transfer Arrays Based On Perylene Diimide

Photosynthesis is the most effective way to utilize solar energy in nature, andphotoinduced electron transfer, the initial process in natural photosynthetic reactioncenter, is the most important way of energy conversion. Therefore the synthesis ofphotoinduced electron transfer arrays is of great importance for solar energycollection and photoelectric conversion. As perylene diimides have fantasticproperties, such as good thermal and chemical stability, high fluorescence quantumyield and adjustable emitting color, the donor-acceptor arrays based on perylenediimide have been widely used. As a kind of typical p type semiconductor material,triphenylamine derivatives are electron-rich as well as porphyrin. Their energy levelsmatch well with perylene diimide, leading to be excellent donors in donor-acceptorarrays based on perylene.We synthetized two new triphenylamine-perylene arrays (MTPA-TRC-PDI,MTPA-TRC-PBI) and a porphyrin-perylene array (HTPPt-PBI), their structures werecharacterized by1H NMR and MS. The UV-Vis spectra show that the interactionsbetween intramolecular chromophores are very weak in the ground-state. The resultsobtained from electrochemical testing show that both LUMO and HOMO energylevels of MTPA and HTPP is higher than perylene. Moreover, the LUMO of TRCmerges with the LUMO of MTPA to form the LUMO+1of triphenylamine-perylenearrays, generating a typical D-A1-A2chromophoric structure wherein MTPA, TRCand perylene modules play the roles of D, A1and A2respectively. Steady-andtransient-fluorescence spectra indicate that a sequential electron transfer process fromLUMO of MTPA to TRC and then to perylene module and hole transfer from theexcited perylene to triphenylamine module occurred in triphenylamine-perylenearrays; meanwhile electron transfer from HTPP to PBI and energy transfer from PBIto HTPP were observed in HTPPt-PBI. Transient absorption spectra show that thelifetimes of charge-separated state MTPA+.-TRC-PDI-.and MTPA+.-TRC-PBI-.canreach as long as22.5ns and74.8ns respectively.Because of good photoelectric properties of perylene diimide, the supramolecularaggregates based on it have attracted much attention in recent years. Theself-assembly of perylene diimide was preliminarily explored through fast solvent diffusion methods, one-dimensional belts and rods were obtained in the mixture ofdichloromethane and methanol.