I am working in MoO3 nanoparticle. when increasing the annealing temperature of MoO3 nanoparticle what will happen in crystallite size (increase or decrease the crystallite size)?
Dear colleague Pradeesh Guna
Have a nice time and good day.
There are many types of annealing; cold annealing, hot annealing, fast and slow annealing. The produced materials may be amorphous (short range order materials, SRO) and always characterized by defects or dangling bonds so it has a random structure and poor order also it may has many pores. So such these materials have low density and strength. Considering the aforementioned reasons the produced material may has a certain thickness, density and strength. Because of annealing the unsaturated defects or localized states may gradually annealed out (decreases), producing a large number of structure bonds. The reduction of the number of unsaturated defects reduces the density of localized states and shifts the amorphous to poly crystalline and/or crystalline state and consequently increases the materials' order and decreases the film thickness. So materials of medium and long range order; MRO, LRO may be introduced. As a resultant, nucleation of different shapes of crystallite size will be formed. The conclusion is high substrate temperature will give the chance of small crystallite size to merge with each other to form large size and consequently grain size with different high diameters will be appeared with high quality poly crystalline structure thus will enhance the structural properties and may all crystallite sizes merged together to form poly or single crystals with different shapes of crystallite size characterized by high density and low thickness. Depends on DTA or DSC thermogram if the annealing temperature is too high (more enough than crystallization temperature or near melting point) the number of structure bonds may has an opposite trends; bonds may be broken and destroyed also the structural units may be deformed to different small sizes and may also decreased.
I wish that be useful and help you.
Yours
A. EL-Denglawey
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