Tunable Efficiency of Nanocomposites for Optoelectronic Applications

Abstract

Metal oxide semiconductor photocatalyst is frequently used to oxidize organic and inorganic compounds in air and water due to its strong oxidation power, non-toxicity, low cost and others. One can achieve significant improvement of photocatalytic activity and photovoltaic efficiency in solar region by modification of metal oxide semiconductor surface with doping of noble metals (Au). Au nanoparticles are commonly used nanomaterials for improving the sensing performance of surface plasmon resonance (SPR) sensors. SPR exhibit strong absorption corresponding to excitation wavelength regions. Consequently, a large electric field due to SPR is excited on the surface of the nanoparticles. The SPR sensitivity is closely related to the excited electric field. Therefore larger the electric field has more sensitive of SPR sensors to the change of its surrounding medium. This can help in increased stability and trapping capability of plasmonic nanoparticles that will boost the development of numerous applications in science and technology. The inclusion of Au nanoparticles in metal oxide semiconductors shows very interesting optical responses including nonlinear effects linked to absorption by SPR. The generated high energetic electrons in the plasmonic nanoparticles may migrate to the adjacent oxide semiconductor if their energies are larger than the barrier at the interface between the metal and semiconductor. The energy of some electrons are not large enough surmount to barrier, they may also be injected into the semiconductor through the tunneling effect. This can generate electron-hole pair, which can increase laser technology, organic pollutants, solar cell, sensor, environmental purification and photo catalytic utilizations.