UV-Induced Grafting of Alkenes to Silicon Surfaces: Photoemission versus Excitons

Autor:	Robert J. Hamers, Rose E. Ruther, Xiaoyu Wang, Jeremy A. Streifer
Rok vydání:	2010
Předmět:	chemistry.chemical_classification Silicon Alkene Exciton chemistry.chemical_element General Chemistry Electron Photochemistry Grafting Biochemistry Catalysis Colloid and Surface Chemistry chemistry Ultraviolet light Recombination
Zdroj:	Journal of the American Chemical Society. 132:4048-4049
ISSN:	1520-5126 0002-7863
DOI:	10.1021/ja910498z
Popis:	The mechanism of photochemical grafting of alkenes to H-terminated silicon has remained poorly understood. Here we demonstrate the importance of a previously unrecognized initiation process, photoelectron ejection (photoemission), as a facile way of initiating photochemical grafting of liquid alkenes to silicon surfaces when using ultraviolet light. A comparison of Si samples with vastly different photocarrier lifetimes showed no difference in the efficiency of alkene grafting. However, differences in the reactivities of different alkenes with different terminal groups that correlate with the electron affinities of these groups were observed. Our results indicate that photoemission is an effective way of initiating grafting because the irreversible nature of photoemission leaves the sample with a net excess of holes that have no corresponding electrons with which to recombine, while in a competing exciton mechanism, the net concentration of holes is limited by recombination processes.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::982c4f48d03048affbd913a1f1fe8ac5 https://doi.org/10.1021/ja910498z Zobrazit plný text záznamu