Size-dependence of melting thermodynamics of nano-Bi

Bismuth nanoparticles serve as core functional units in various electronic devices. Due to the size effect, the particle size of nano-Bi significantly influences its melting thermodynamic properties, thereby influencing the development and application of corresponding functional materials. In this paper, firstly, the theoretical relationships between the melting temperature, integral melting thermodynamic properties of nano-bismuth and particle size were derived, respectively. Experimentally, spherical nano-Bi with different particle sizes (average radius ranging from 39.94 nm to 85.85 nm) were prepared by a solvothermal method. The melting temperature, melting enthalpy and melting entropy were measured using a differential scanning calorimeter. The experimental results were compared with the theoretical predictions, revealing that the melting temperature, melting enthalpy and melting entropy of nano-bismuth decrease with a reduction in particle size. Furthermore, within the investigated particle size range, these melting thermodynamic properties exhibit a linear correlation with the reciprocal of the particle size. This study elucidates the regulatory mechanism of particle size on the melting thermodynamics of nano-Bi. It not only deepens the theoretical understanding of nanothermodynamics but also provides crucial design principles for the performance optimization of nano-Bi-based devices.