Generation of singlet oxygen at room temperature mediated by energy transfer from photoexcited porous<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi></mml:mrow></mml:math>

Fujii, Minoru; Minobe, Shingo; Usui, Motofumi; Hayashi, Shinji; Groß, E.; Diener, J.; Kovalev, D.

doi:10.1103/physrevb.70.085311

Cited by 49 publications

(43 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The lifetime of generated singlet oxygen can be estimated from a decay curve of the singlet-oxygen PL. The lifetime is found to be about 3.9 ms, [65] which is shorter than the literature value (21 ms). [2] The shortening of the lifetime may result from the collisions of singlet oxygen with the walls of porous Si pores and the resultant non-radiative relaxation, because a majority of the singlet oxygen is generated in the pores.…”

Section: Singlet-oxygen Generation In Liquidscontrasting

confidence: 54%

“…This emission line can thus be assigned to the radiative relaxation of D PL intensity for a solution containing oxidized powder is much smaller than for a solution containing fresh powder. [65] Direct evidence for the photosensitized formation of singlet oxygen is obtained from PL excitation spectra. In Figure 14, the intensity of the singlet-oxygen PL is plotted as a function of the excitation energy.…”

Section: Singlet-oxygen Generation In Liquidsmentioning

confidence: 99%

See 1 more Smart Citation

Silicon Nanocrystals: Photosensitizers for Oxygen Molecules

2005

View full text Add to dashboard Cite

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.

show abstract

Section: Singlet-oxygen Generation In Liquidscontrasting

confidence: 54%

Section: Singlet-oxygen Generation In Liquidsmentioning

confidence: 99%

Silicon Nanocrystals: Photosensitizers for Oxygen Molecules

2005

View full text Add to dashboard Cite

show abstract

“…[91] While we attributed the quenching mechanism to electron transfer, it was later shown to be predominantly one of energy transfer. [103] Oxygen is a triplet state, diradical molecule in its ground state. The energy transfer process generates singlet oxygen (Equations 4 and 5), which is a powerful oxidant that is used in the treatment of skin cancer.…”

Section: Quenching Mechanisms: Charge and Energy Transfermentioning

confidence: 99%

Photoluminescence‐Based Sensing With Porous Silicon Films, Microparticles, and Nanoparticles

Sailor

2009

Adv Funct Materials

150

107

View full text Add to dashboard Cite

Here, chemical sensors made from porous Si are reviewed, with an emphasis on systems that harness photoluminescence and related energy‐ and charge‐transfer mechanisms available to porous Si‐derived nanocrystallites. Quenching of luminescence by molecular adsorbates involves the harvesting of energy from a delocalized nanostructure that can be much larger than the molecule being sensed, providing a means to amplify the sensory event. The interaction of chemical species on the surface of porous Si can exert a pronounced influence on this process, and examples of some of the key chemical reactions that modify either the surface or the bulk properties of porous Si are presented. Sensors based on micron‐scale and smaller porous Si particles are also discussed. Miniaturization to this size regime enables new applications, including imaging of cancerous tissues, indirect detection of reactive oxygen species (ROS), and controlled drug release. Examples of environmental and in vivo sensing systems enabled by porous Si are provided.

show abstract

“…In addition, photoexcitation of quantum confined silicon nanostructures in aqueous aerated media has been shown to produce singlet oxygen [32][33][34][35]. The ability of the porous Si nanostructure to degrade into relatively harmless silicic acid byproducts makes porous Si an attractive alternative to molecular (typically porphyrinbased [195]) sensitizers for photodynamic therapy [196,197].…”

Section: Cancer Treatmentmentioning

confidence: 99%

Porous silicon in drug delivery devices and materials☆

Anglin

Cheng

Freeman

et al. 2008

Advanced Drug Delivery Reviews

807

618

View full text Add to dashboard Cite

Porous Si exhibits a number of properties that make it an attractive material for controlled drug delivery applications: The electrochemical synthesis allows construction of tailored pore sizes and volumes that are controllable from the scale of microns to nanometers; a number of convenient chemistries exist for the modification of porous Si surfaces that can be used to control the amount, identity, and in vivo release rate of drug payloads and the resorption rate of the porous host matrix; the material can be used as a template for organic and biopolymers, to prepare composites with a designed nanostructure; and finally, the optical properties of photonic structures prepared from this material provide a self-reporting feature that can be monitored in vivo. This paper reviews the preparation, chemistry, and properties of electrochemically prepared porous Si or SiO 2 hosts relevant to drug delivery applications.

show abstract

Generation of singlet oxygen at room temperature mediated by energy transfer from photoexcited porousSi

Cited by 49 publications

References 13 publications

Silicon Nanocrystals: Photosensitizers for Oxygen Molecules

Silicon Nanocrystals: Photosensitizers for Oxygen Molecules

Photoluminescence‐Based Sensing With Porous Silicon Films, Microparticles, and Nanoparticles

Porous silicon in drug delivery devices and materials☆

Contact Info

Product

Resources

About