Table 4.

The comparison of key properties of different synthetic methods [61–63].

Synthetic method	Synthesis	Reaction temp. (°C)	Reaction time	Solvent	Surface-capping agents	Size distribution	Shape control	Yield
Coprecipitation	Very simple	20–90	Minutes	Water	During/after reaction	Relatively narrow	Not good	High
Microemulsion	Complicated	20–50	Hours	Organic agents	During reaction	Relatively narrow	Good	Low
Thermal decomposition	Complicated	100–320	Hours-days	Organic agents	During reaction	Very narrow	Very good	High
Hydrothermal	Simple	200–250	Hours-days	Water-ethanol	During reaction	Very narrow	Very good	Medium