Antireflection Films For Solar Cells

It is important work for scientific researchers to improve utility ratio of solar energy, especially to improve conversion efficiency of solar cells, there are many ways which can be used to improve it, depositing antireflection films on solar cells is the most doable one, and can debase the cost of solar cells. At present, the more wide ways are spray and brush and so on, but these ones have many disadvantages, for example polluting environment, poor adhesion etc. magnetron sputtering is a green one and the adhesion of the film with the substrate is very good. The materials of antireflection films are MgF2, Si3N4, Ta2O5 etc, these materials also have many disadvantages themselves. SiO2, TiO2 are the good materials as antireflection films, and TiO2 have characteristics of photocatalytic, self-cleaning and antifogging films and so on.This paper aims to study antireflection films for solar cells.Firstly, The TiO2 thin films are deposited by DC reactive magnetron sputtering apparatus, and characterlized by n&k analyzer1200, X-ray diffraction spectroscopy (XRD), scanning electronic microscopy(SEM), ALPHA-STEP500. and it was analyzed that the effect on performance and structure of films with the change of argon flow, total gas pressure, the substrate-to-target distance and temperature. The results is the following.(1)With the condition of table 4.1, the low reflectance vale will move towards the center wavelenghth(550nm), the influence on refractive index of the films is very little, the extinction coefficient(k) have trend of increase and the thickness of the films decrease when increasing the oxygen flow. The rutile phase increase and the surface morphology is dense and smoothnes with increasing the oxygen flow.(2) With the condition of table 4.2, the average reflectance decreases and the low reflectance vale moves towards shortwave, the influence on the extinction coefficient(k) of the films is very little, refractive index has trend of decrease and the thickness of the films decrease when increasing the total gas pressure, and the refractive index fix on a constant value when the total pressure exceeds a certain value. The phase of TiO2 change from rutile to anatase and the size of surface grain change from big to small.(3) With the condition of table 4.3, with increasing of temperature the average reflectance value decreases and the minimum reflectance point moves towards red direction. Furthermore, temperature has little effect on the extinction coefficient (k). However, the refractive index value decreases remarkably when the temperature reaches about 240℃, but it does not change much when the temperature is below 180℃and the thickness of the films increase when increasing the temperature. With increase of temperature the crystal structure...