Photosensitizer

A photosensitizer being used in photodynamic therapy

Photosensitizers are light absorbers that alter the course of a photochemical reaction. They usually are catalysts.[1] They can function by many mechanisms, sometimes they donate an electron to the substrate, sometimes they abstract a hydrogen atom from the substrate. At the end of this process, the photosensitizer returns to its ground state, where it remains chemically intact, poised to absorb more light.[2][3][4] One branch of chemistry which frequently utilizes photosensitizers is polymer chemistry, using photosensitizers in reactions such as photopolymerization, photocrosslinking, and photodegradation.[5] Photosensitizers are also used to generate prolonged excited electronic states in organic molecules with uses in photocatalysis, photon upconversion and photodynamic therapy. Generally, photosensitizers absorb electromagnetic radiation consisting of infrared radiation, visible light radiation, and ultraviolet radiation and transfer absorbed energy into neighboring molecules. This absorption of light is made possible by photosensitizers' large de-localized π-systems, which lowers the energy of HOMO and LUMO orbitals to promote photoexcitation. While many photosensitizers are organic or organometallic compounds, there are also examples of using semiconductor quantum dots as photosensitizers.[6]

  1. ^ "Photosensitization". IUPAC Gold Book. International Union of Pure and Applied Chemistry. 2014. doi:10.1351/goldbook.P04652.
  2. ^ Cite error: The named reference :02 was invoked but never defined (see the help page).
  3. ^ Zhang Y, Lee TS, Petersen JL, Milsmann C (May 2018). "A Zirconium Photosensitizer with a Long-Lived Excited State: Mechanistic Insight into Photoinduced Single-Electron Transfer". Journal of the American Chemical Society. 140 (18): 5934–5947. doi:10.1021/jacs.8b00742. PMID 29671586.
  4. ^ "Photosensitization". IUPAC Compendium of Chemical Terminology. 2009. doi:10.1351/goldbook.P04652. ISBN 978-0-9678550-9-7.
  5. ^ Alger M (1996). Polymer science dictionary (2nd ed.). London: Chapman & Hall. ISBN 978-0412608704.
  6. ^ Liu Y, Ma Y, Zhao Y, Sun X, Gándara F, Furukawa H, et al. (January 2016). "Weaving of organic threads into a crystalline covalent organic framework". Science. 351 (6271): 365–9. Bibcode:2016Sci...351..365L. doi:10.1126/science.aad4011. PMID 26798010.