extrinsic absorption

of solid photocatalysts
https://doi.org/10.1351/goldbook.14010
Absorption of ultraviolet, visible, or infrared radiation in semiconductors and insulators corresponding to optical transitions of electrons from defect energy levels (within the bandgap energy) to conduction band levels, or holes to valence band levels (photoionisation of defects), or from the ground state level to excited levels of a given intrinsic defect of any sort.
Notes:
  1. Typically, extrinsic absorption bands are a few tenths to a few \(\pu{eV}\) distant from the fundamental absorption edge in semiconductors and insulators. The red limits of photocatalytic reactions are determined by photoexcitation of photocatalysts in the extrinsic absorption bands.
  2. Doping of a catalyst creates an extrinsic defect.
Source:
PAC, 2011, 83, 931. (Glossary of terms used in photocatalysis and radiation catalysis (IUPAC Recommendations 2011)) on page 951 [Terms] [Paper]
Citation: 'extrinsic absorption' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.14010 RIS BibTex EndNote
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