14011 IUPAC Gold Book - extrinsic defect 10.1351/goldbook.14011 14011 current synonym: extrinsic surface defect 1 Imperfection in a solid semiconductor (or insulator) connected with surface defects of any sort involving extrinsic chemical units in relation to the chemical formula of the solid, particularly adsorbed species of any sort. These extrinsic surface defects play an essential role in heterogeneous photocatalysis. For example, they can serve as photocatalytic centres (sites). Surface defects, as well as bulk defects located in the near-surface region, can serve as entities that absorb ultraviolet, visible, or infrared radiation and generate free charge carriers. Surface defects can trap charge carriers and serve as recombination centres, thereby influencing the concentration of photocarriers at the surface of photocatalyst particles. Doping of a catalyst creates an extrinsic defect. heterogeneous photocatalysis https://goldbook.iupac.org//terms/view/14018 photocarriers https://goldbook.iupac.org//terms/view/14040 photocatalytic centres https://goldbook.iupac.org//terms/view/14043 recombination centres https://goldbook.iupac.org//terms/view/14081 PAC, 2011, 83, 931. 'Glossary of terms used in photocatalysis and radiation catalysis (IUPAC Recommendations 2011)' on page 952 (https://doi.org/10.1351/PAC-REC-09-09-36) https://goldbook.iupac.org/terms/view/14011/html https://goldbook.iupac.org/terms/view/14011/json https://goldbook.iupac.org/terms/view/14011/plain Citation: 'extrinsic defect' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.14011 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-06-29T13:26:49+00:00