Growth of ultrasmall nanoparticles based on thermodynamic size focusing

This study presents a new concept to synthesize quantum dots or nanoparticles with smaller size (<2 nm) based on the thermodynamic size focusing. Conventionally, control over crystal size is achieved by interrupting crystal growth and/or limiting the reaction rate at lower temperature. Alternatively, we synthesized ultrasmall nanoparticles via a simple thermal quenching-isothermal annealing process called the thermal size focusing. This approach, avoiding the difficulty of controlling the rapid nanoparticles' growth in the interruption method or long synthesis time in the low-temperature process, provides an efficient way for obtaining ultrasmall nanoparticles.