Nucleation of plasmonic nanobubbles induced by the thermoplasmonic effect of gold nanoparticle dimers

• An LBM method was developed to simulate the evolution of plasmonic nanobubbles generated by nanoparticle dimer. • The fluence threshold of nanobubble nucleation exhibits a monotonic dependence on dimer size. • The sequence of nucleation in a dimer composed of two nanoparticles with different sizes can be altered by adjusting the laser polarization direction. Plasmonic nanobubbles are increasingly investigated for their distinctive optical properties. Understanding the mechanisms driving nanobubble formation is essential for controlling nanobubbles and optimizing photothermal effects in applications such as nanoparticle manipulation, solar vapor generation, and biomedicine. This work aims to provide a comprehensive description of the nanobubble nucleation on gold nanoparticle dimers in water. Under laser excitation, since the near-field coupling of surface plasmon resonances and the heat transfer between plasma and water can be modulated by adjusting the distance between the particles, the interparticle coupling effect in nanoparticle dimers results in unique optical and photothermal properties. Using the Lattice Boltzmann method, the interplay of heat transfer coupling and thermoplasmonics effect arising from plasmon coupling effects and their role on the nanobubble nucleation generated by gold nanoparticle dimers is revealed. Such effects result in a monotonic dependence of fluence threshold on dimer size, unlike the non-monotonic dependence in isolated nanoparticles. Interestingly, for the asymmetric plasma nanostructure, a dimer composed of two nanoparticles with different sizes, the position of nanobubble nucleation can be controlled by simply changing the incident laser polarization direction under the influence of the two coupling effects. This work establishes a theoretical framework for understanding the collective photothermal behavior of nanoparticles in nanoparticle solutions.