photoninduced

Photon-induced, often written as photoinduced, describes processes initiated by the absorption of photons, by which light energy drives photophysical or photochemical transformations. It spans gas, liquid, and solid phases, including surfaces and interfaces, and encompasses a broad range of wavelengths from the ultraviolet through the visible to the near-infrared, corresponding to the energy of the absorbed photons.

Mechanisms include photophysical processes such as excitation to singlet or triplet states, fluorescence, phosphorescence, intersystem crossing, internal conversion; and photochemical processes such as bond cleavage, isomerization, electron transfer, or radical formation. In some cases, multiple photons are absorbed (two-photon or multiphoton processes), enabling reactions with sub-bandgap energies or high spatial precision.

Applications and examples: photocatalysis, photopolymerization for coatings and 3D printing, photodissociation in atmospheric chemistry, photoinduced electron transfer in molecular electronics, photoinduced desorption from surfaces, and light-driven phase transitions in materials such as some transition-metal oxides and organic-inorganic perovskites. In solar energy, photon-induced charge separation underpins photovoltaic operation and photoelectrochemical cells.

Characterization commonly employs spectroscopy and time-resolved methods, including pump-probe and transient absorption, to study excited-state lifetimes, quantum yields, and reaction pathways. The term is used broadly across chemistry, physics, and materials science and is often used interchangeably with photoinduced or photochemical when describing light-driven processes.