NOVELTY - Synthesizing nanocrystals, involves: contacting a first precursor, a ligand compound, and a second precursor in a solvent having a boiling point of less than or equal to 150 degrees C and a polarity index of less than or equal to 5; and performing a thermal decomposition reaction of the first precursor and the second precursor at a higher pressure than atmospheric pressure and at a higher temperature than a boiling point of the solvent, where at least one of the first and second precursor is a metal-containing precursor.    USE - For synthesizing nanocrystals, particularly metal nanocrystals or semiconductor nanocrystals (Claimed). The semiconductor nanocrystals are used in various fields such as a light emitting diode (LED), a solar cell, and a biosensor.    ADVANTAGE - The present method resolves problems of the prior art by synthesizing nanocrystals through a pressurized reaction in the solvent having a boiling point of less than or equal to 150 degrees C. In this process, a temperature of a reaction system is allowed to increase above the boiling point of the solvent, and thus, even a low boiling point solvent may be utilized to carry out a high temperature reaction that is required for obtaining high quality nanocrystals. Accordingly, the amount of the solvent remaining on the surface of the crystals as prepared is very small and the solvent remaining on the surface may be readily removed by washing. In addition, the nanocrystals having a smaller amount of the organic material may maintain desired properties such as crystallinity, full width at half maximum, and particle size.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a nanocrystal composition comprising a metal nanocrystal or a semiconductor nanocrystal to a surface of which a ligand compound is coordinated, where the metal nanocrystal or the semiconductor nanocrystal to a surface of which the ligand compound is coordinated has a solvent content of less than or equal to 20 wt.%, based on the total wt. of the nanocrystal and an organic material coordinated to it, where the organic material comprises the ligand compound and the solvent.