Optical properties energy conversion

Chemistry produces many materials, other than drugs, that have to be optimized in their properties and preparation. Chemoinformatics methods will be used more and more for the elucidation and modeling of the relationships between chemical structure, or chemical composition, and many physical and chemical properties, be they nonlinear optical properties, adhesive power, conversion of light into electrical energy, detergent properties, hair-coloring suitabHty, or whatever. 

Following these studies were a series of works which examined the SH response from polycrystalline and crystalline silver electrode surfaces biased within the ideally polarizable region [42-44, 54-64], These studies showed the sensitivity of SHG to adsorption of ions to the electrode surface. More importantly, they showed that the sensitivity arose from the changes in the optical properties of the electrode surface itself, and not from the optical properties of the ionic and simple molecular species at the surface. Conversely, the SH response from an adsorbate, such as a dye molecule, can become an important factor if either the fundamental or SH photon energy is resonant with electronic transitions in the adsorbate [65, 66]. For more details on these SH studies of both ORC effects and adsorption phenomena on polycrystalline substrates, the reader is referred to Refs. 7 and 9. 

In recent years there has been a considerable amount of research on transition metal complexes due to the large number of potential or already realized technical applications such as solar energy conversion through photo-redox processes, optical information and storage systems, photolithographic processes, etc. Moreover, metal complexes are also of considerable importance in biology and medicine. Most of these applications are directly related to the electronic and vibronic properties of the ground and lowest excited states. 

With rich luminescent properties, long-lived CT excited states and a variety of bimolecular photochemical reaction pathways, the mixed-ligand square-planar diimine dithiolene complexes of d8 metal ions show great promise for solar-energy conversion, as luminescent probes or in photocatalytic applications. Complexes of this type have also received attention for the nonlinear optical properties, such as second harmonic generation, related to the MMLL CT excited state (14, 129). 

Another important characteristic of semiconductors is their optical absorption properties. The optical properties of semiconductors are crucial to their uses as photovoltaic energy conversion devices, photonic detectors, light-emitting diodes, solid state lasers, and optical switches see Semiconductor Interfaces). Some semiconductors absorb both visible and ultraviolet light, while others only absorb photons in the... 

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