Light-induced photoluminescence enhancement in semiconductor nanomaterials: mechanisms and influencing factors

Semiconductor nanomaterials exhibit unique properties such as size-tunable chemical and physical properties, making them widely applicable in advanced fields, including optoelectronic devices, biomedical imaging, solar cells, and ultra-sensitive sensors. Many studies have revealed that light irradiation can significantly enhance the photoluminescence intensity of semiconductor nanomaterials, offering a promising approach to improve their luminescence efficiencies. This review comprehensively summarizes the factors contributing to light irradiation-induced photoluminescence enhancement (LI-PLE) based on existing literature, systematically categorizing them into seven pathways: (1) surfactant/ligand rearrangement and shell reconstruction; (2) photoactivation due to oxygen; (3) photoactivation due to water; (4) photoactivation due to water and oxygen; (5) photothermal annealing; (6) photoinduced surface passivation by polymer molecules; and (7) charging effect of trapped electrons. These pathways are primarily attributed to the healing or reduction of surface/interface defects. While some mechanisms have been experimentally validated, many explanations for the observed luminescence enhancement remain largely speculative. However, based on the information presented in the table, we summarize the possible factors contributing to LI-PLE across various material systems under specific conditions. Finally, we anticipate future research directions in this field, emphasizing the need for the development of more precise experimental techniques and the establishment of universal theoretical models to gain a deeper and more accurate understanding of the mechanisms underlying light irradiation enhancement. Such advancements will offer theoretical guidance for optimizing the performance of semiconductor optoelectronic devices.