nanoparticles has greatly become a topic of interest. This is because the conventional chemical methods are expensive and require the use of chemical compounds or organic solvents as reducing agents which are toxic as well [C.Manson, 2012]. Green chemistry reduces the risk of pollution at source level and it is enhanced to prevent waste rather than treat or clean up waste after it is formed. The principle focuses on choice of reagents which are ecofriendly. Although physical and chemical methods are
Moreover we have found that the sol-gel chemistry which is dividing into two categories aqueous and non-aqueous; has many benefits likely easily produce metastable materials, homogeneity in structure with high purity at different temperatures with simple laboratory equipment. Also its gives various morphologies at synthesis stage (chemical transformation of the molecular precursor to the oxidic network). The aqueous sol-gel chemistry has vastly popular to fabricate bulk metal oxides; they
compared to simple ZnO nanoparticle mesoporous films. To the best of our knowledge, the highest η (7.5%) was reported by hierarchical assembled ZnO nanocrystallites, which offer large specific surface area for dye loading while poly-dispersed aggregates act as efficient light scatters, enhancing the probability of photon absorption (Pandey, et al. 2017, Zhang Q et al. 2008, Petra J et al. 2003, Memarian N et al. 2011). Another strategy to boost η in ZnO DSSCs is the application of a ZnO buffer layer
processes. Photocatalysis is a simple and promising technique for solving various current environmental issues. Semiconductor absorbents offer a great potential for eliminating the organic pollutants present. Semiconductor photocatalysts for example, zinc oxide and titanium oxide have been applied to degradation of contaminants in waste water and air. On common example,For photocatalysis process, ZnO has also been considered as a suitable alternative for TiO2 due to The band-gap energy of ZnO is similar