Perylene Compounds Optical And Electrical Properties

The solar energy is abundant and infinite green energy source and it is one of thebest ways to solve the energy crisis. In recent years, Dye-Sensitized Solar Cells(DSPEC)have be payed more and more attention because of large-area fabrication, potentiallylow cost and ease of designing materials based on the molecular level. However, thereare many problems to solve, such as improving the properties of the electrode,counter-electrode, sensitizing-dyes, electrolytes. By these ways photon-to-currentconversion efficiency can be increased.Two types of perylene imide derivatives (10 compounds) are synthesized, whichhave different structures and substituents differ from electro-attraction or repulsionproperties. The purification methods are also carried out.The series of synthesized dyes have been determinated by means of UV-VIS, IR,FES and SPS. Theirs structures and photoelectric properties have been investigated andcompared. These compounds then have been self-assembled to the nanocrystalline TiO₂electrodes. The photon-to-current conversion efficiency of dye-sensitizednanocrystalline TiO₂ electrodes is researched using Photocurrent action spectra and EIS.It's found out that many factors can be influenced photon-to-current conversionefficiency in the systems, such as lengths of substituted carbon chain, whether or notexist conjugate structure and power of electron attraction or repulsion on substituent. Ifadequate imide substituent groups have been introduced to perylene systems, it must bein favor of electron-transfer within moleculars and promote separation of electrons andholes, restrain recombination of electrons and holes. So the photon-to-currentconversion efficiency must be enhanced. As photosensitive agents,these types ofcompounds have been self-assembled to the nanocrystalline TiO₂ electrodes, strongerphoto-electronic responds in the VIS region can be observed. Absorption of solar rays by TiO₂ electrodes is largely expanded and photon-to-current conversion efficiency ofsolar energy cells must be greatly increased.