Dear Meetei,

The parameters change from type and method used for the synthesis of  different nanomaterials to be synthesized, whereas some common parameters are listed below:

By varying the temperature, stirring speed, acidity , ionic strength of the reaction mixture, short nucleation burst and slow nuclei growth controlling size and distribution in the initial step is important for imparting monodispersity to the synthesized particles whereas the size and shape can also be altered with the proper selection of the precursor salts (e.g. sulfates, chlorides and nitrates).

I hope this  may be of some help to you

A large number of methods are used for producing nano size for scientific studies and applications. annealing or growth  temperature ("low", that is close to room temperature or "high", that is T ~ 1000 °C)  decreasing the size of crystal i worked on nano rod Chang the the growth temperature in range 600-1000  we concluded  the diameter of crystal  decreased

There are several methods are known for Nanomaterials synthesis.  One among them is sol-gel method.  In this, the solvent density, the hydrolyzing rate of alkoxides, catalyst molecular size, temperature of the reaction system, time are some of them.

It is worth noting that the exact mechanism for nanoparticle formation is not completely understood.  For gold, and metallic nanoparticles in general, important physical factors are: stirring speed, temperature, stabilizer structure and size, time, and media viscosity.  I hope this helped!

Dear Meetei,

The parameters change from type and method used for the synthesis of  different nanomaterials to be synthesized, whereas some common parameters are listed below:

By varying the temperature, stirring speed, acidity , ionic strength of the reaction mixture, short nucleation burst and slow nuclei growth controlling size and distribution in the initial step is important for imparting monodispersity to the synthesized particles whereas the size and shape can also be altered with the proper selection of the precursor salts (e.g. sulfates, chlorides and nitrates).

I hope this  may be of some help to you

Well, I would agree with Ms. Purva that it depends upon your experiment. Which method are you using. If you are using some chemical methods such as hydrothermal method then the conditions would be different. If you are using CVD method then the conditions would be entirely different. So, I think you need to be more specific about the question regarding what exactly you are doing. But in general, in case of chemical method, different reaction parameters such as concentration of reactants, speed/intensity of stirring/sonication and their time, temperature of the reaction and the duration for the reaction are some key factors that affect the size of grown nanocrystals. On the other hand, if you use CVD, for example, then the parameters include the reaction time, temperature, distance between the substrate and reactant sample etc. I hope it can help you in some better understanding.

Good luck!

Temperature, pH value, precursors used, calcination time and temperature, pressure maintained during synthesis, stirring speed etc are few factors that affect the size and shape of nanparticles. Different substances react differently to these conditions.

I hope this would be helpful

In solution, nanocrystals are protected from aggregation by using capping molecules, and surfactants. The type and concentration of the stabilizers have an influence on particle size. Ostwald ripening, which strongly depends on temperature, affects the particle size. On increasing temperature small particles dissolves and settle over other to form large particle. So optimum temperature is required for nanoparticle synthesis.  

Thank you every one for the answers/suggestions you have provided. It benefited me a lot. As a consequence of the above question, I will raise a new question "What is the Physics behind the change in size of a nano-material/crystal/particle ?" I will ask this question as a new/separate question. Answer in the new/separate question is preferable as it will maximize number of audience/researcher.