Of Sio <sub>, 2 </ Sub> Nanoparticles On The Optical Device Applications

SiO2 nanoparticles has been widely used in optical and optoelectronic devices since its excellent optical properties. The SiO2 colloid nanoparticles was fabricated by the method of Stober, and was self-assembly to various of optical devices using Electrostatic Self-assembly Method (ESAM). Electrostatic attraction is a useful interaction for assembling materials such as polyelectrolytes and charged colloidal particles.,which is easy to operate and low-cost without complicated large vacuum systems. In this paper, the applications of SiO2 nanoparticles in antireflection coating for solar cell and Enhanced efficiency of light emiiting diodes.Usually, Rigorous Coupled-Wave Analysis (RCWA) method is used to simulate the antireflection effect in surface textured structures. However, solving RCWA is relatively complicated and time-consuming. Instead, we utilize a simple alternative method, thin film characteristic matrix (TFCM) to calculate reflectivity of such structures. It is proven that, for the same nanostructure, TFCM's emulation results consist well with those of RCWA's.We report here a new structure for broadband antireflection coating (AR) with solution based process. It is low-cost and compatible with large scale manufacturing. The coatings are prepared by (1) depositing SiO2 sol-gel film on a glass substrate, (2) subsequently depositing SiO2 single-layer particle coating through electrostatic attraction, (3) finally depositing another very thin SiO2 sol-gel film to improve the mechanical strength of the whole coating structure. The AR effect of the coating of each layer is studied with transmittance and reflectance spectra at normal incidence. The low reflectance of this coating could become omnidirectional, since the silica particles are spherical in shape. The mechanical strength is immensely improved because of the additional thin SiO2 sol-gel layer. The average reflection losses of the coating are reduced by applying our three-layer structure AR-coating onto glass substrate. The surface texture can be applied to the substrates of different materials and shapes as an add-on coating.A non-closed packed SiO2 nanoparticle array on sapphire substrate using electrostatic self-assembly is fabricated by dip-coating technique. This structure can be worked as patterned sapphire substrate, and is independent on the subsequent epitaxial lateral overgrowth. As a result, the light output power of LED with SiO2 nanoparticle substrate was 17.8% greater than that of conventional LED, while the luminous flux was enhanced by 57%. Strong enhancement in output power is attributed to better epitaxial quality and more reflection at the interface of GaN/Sapphire.