Charge carrier lifetime in DLC films

Dłużniewski, M.; Kania, Sylwester

doi:10.1016/j.diamond.2004.07.015

Cited by 4 publications

(1 citation statement)

References 7 publications

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“…In a recent study, we found that patterned photochemical grafting of TFAAD on single-crystal diamond yielded a broad transition region while an identical experiment on nanocrystalline diamond yielded a sharp chemical pattern, and we suggested that the diffusion of holes may be important. Our present results on amorphous carbon reinforce this picture: the lifetime of photogenerated charge carriers in amorphous carbon can be very long, up to the millisecond range, and diffusion lengths have been estimated to be up to ∼700 nm, − consistent with the width of the observed 1-dodecene reaction front.…”

Section: Discussionsupporting

confidence: 87%

Enhancement of Photochemical Grafting of Terminal Alkenes at Surfaces via Molecular Mediators: The Role of Surface-Bound Electron Acceptors

et al. 2008

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The use of ultraviolet light to functionalize the surface of carbon-based materials with terminal alkenes has emerged as a way to overcome the high chemical stability of these surfaces to create functional interfaces. It was previously shown that surface-bound trifluoroacetic acid protected 10-aminodec-1-ene (TFAAD) can be used to promote the grafting of unreactive alkenes using 254 nm light, but the mechanism by which this enhancement occurs was not understood. Here, we present a detailed study of how surface-bound TFAAD enhances the grafting of organic molecules to the surface of hydrogen-terminated amorphous carbon. Infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy experiments show that pregrafting TFAAD onto carbon surfaces greatly enhances the subsequent grafting of 1-dodecene, dodecane and dodecane-d 26 by locally facilitating photoemission of electrons. Using a photopatterned TFAAD “seed” layer, we demonstrate that subsequent grafting of these hydrocarbons is enhanced in regions immediately adjacent to the seed and proceeds almost exclusively parallel to the carbon surface. The roles of liquid-phase radical species, valence band holes, and the photochemical fragmentation of surface species in controlling the overall reaction mechanism are discussed.

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Section: Discussionsupporting

confidence: 87%

Enhancement of Photochemical Grafting of Terminal Alkenes at Surfaces via Molecular Mediators: The Role of Surface-Bound Electron Acceptors

et al. 2008

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Synthesis and Optoelectronic Properties of Hexahydroxylated 10‐O‐R‐Substituted Anthracenes via a New Modification of the Friedel–Crafts Reaction Using O‐Protected ortho‐Acetal Diarylmethanols

Bodzioch

Marciniak

Różycka‐Sokołowska

et al. 2012

Chemistry A European J

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A new modification of the Friedel-Crafts type intramolecular cyclization involving O-protected ortho-acetal diarylmethanols as a new type of reactant, was carried out for the first time in a medium containing a large amount of water at room temperature and enabled synthesis of a series of electron-rich, hexahydroxylated 10-O-R-substituted anthracenes, where R is an alkyl (Me, nBu, n-C(16)H(33)) or arylalkyl group (CH(2)Ph, CH(2)-2-Napht, CH(2)C(6)H(4)CH(2)OAr) and also evaluation of their electronic and optoelectronic properties in solution, crystal, and solid thin film. In this transformation, a central 10-O-R-substituted benzene ring was formed, fused to rings originating from two independent aromatic aldehydes. The reaction proceeded via two identified mechanisms involving acetal and/or free aldehyde groups. The acid sensitive acetal and dibenzyl alkoxy functions have never been used together in the intramolecular Friedel-Crafts type cyclization. The new compounds revealed deep blue fluorescence and quantum yields in solution around 0.3. The electrical properties investigated for thin films obtained by vacuum deposition on glass were 10-O-R-substituent dependent and showed much faster transient current decay in the case of the 10-O-CH(2)Ph derivative than for the material with a 10-O-Me substituent (the lifetime of charge carriers was 25 times shorter in this case). The AFM images of thin films, Stokes shifts, and X-ray analysis of π-stacking interactions in crystals of the new materials have been also obtained.

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Charge carrier lifetime in boron carbide thin films

Bao

Yan

Chrisey

2011

Applied Physics Letters

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Charge carrier lifetime is a critical parameter to improve the conversion efficiency of radioisotope power sources and the sensitivity of neutron detectors based on boron carbide thin films. The effective charge carrier lifetime in B 4 C boron carbide films has been investigated by using transient photoconductivity decay. The carrier lifetime depends on the characterization conditions as well as the structure of the films. The measured lifetime could be up to ϳ1 ms in B 4 C film, which is much longer than that in conventional semiconductors. The photoresistance change in B 4 C films and the photovoltaic response of B 4 C / n-Si͑100͒ heterojunctions have also been studied.

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Charge carrier lifetime in DLC films

Cited by 4 publications

References 7 publications

Enhancement of Photochemical Grafting of Terminal Alkenes at Surfaces via Molecular Mediators: The Role of Surface-Bound Electron Acceptors

Enhancement of Photochemical Grafting of Terminal Alkenes at Surfaces via Molecular Mediators: The Role of Surface-Bound Electron Acceptors

Synthesis and Optoelectronic Properties of Hexahydroxylated 10‐O‐R‐Substituted Anthracenes via a New Modification of the Friedel–Crafts Reaction Using O‐Protected ortho‐Acetal Diarylmethanols

Charge carrier lifetime in boron carbide thin films

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