In nanomaterials, optical excitation can occur through various mechanisms, such as:
1. Band-to-Band Transitions: Electrons absorb photons and transition from the valence band to the conduction band in semiconductors. 2. Plasmon Resonance: In metallic nanoparticles, collective oscillations of electrons (plasmons) can be excited by light, leading to enhanced electromagnetic fields. 3. Exciton Formation: In quantum dots and other nanostructures, electron-hole pairs (excitons) are formed upon light absorption.
