Silicon nanocrystals: Photosensitizers for oxygen molecules

2019-09-11 20:50:21

silicon O2 Oxygen nanocrystals spin

责任者: Kovalev, Dmitri;Fujii, Minoru 单位: Physics Department, Technical University of Munich, D-85748 Garching, Germany 来源出处: Advanced Materials,2005,17(21):2531-2544 摘要: Molecular oxygen plays an important role in many of the chemical reactions involved in the synthesis of biological life. In this review, we explore the interaction between O2 and silicon nanocrystals, which can be employed in the photosynthesis of singlet oxygen. We demonstrate that nanoscale Si has entirely new properties owing to morphological and quantum size effects, i.e., large accessible surface areas and excitons of variable energies and with well-defined spin structures. These features result in new emerging functionality for nanoscale silicon: it is a very efficient spin-flip activator of O2, and therefore, a chemically and biologically active material. This whole effect is based on energy transfer from long-lived electronic excitations confined in Si nanocrystals to surrounding O2 via the exchange of single electrons of opposite spin, thus enabling the spin-flip activation of O2. Further, we discuss the implications of these findings for physics, chemistry, biology, and medicine. © 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim. 关键词: Nanostructured materials;Silicon;Photosensitizers;Oxygen;Photosynthesis;Electric excitation;Energy transfer;Biological life;Singlet oxygen;Silicon nanaocrystals