Comparison of extra electrons in colloidal n-type Al3+-doped and photochemically reduced ZnO nanocrystals

Schimpf, Alina M.; Ochsenbein, Stefan T.; Buonsanti, Raffaella; Milliron, Delia J.; Gamelin, Daniel R.

doi:10.1039/c2cc34635d

Cited by 77 publications

(156 citation statements)

References 21 publications

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“…Plasmonic semiconductor oxide nanocrystals such as Al-doped ZnO (AZO), [1][2][3] indium-doped ZnO (IZO), 3,4 Ga-doped ZnO (GZO), 3 Sn-doped In 2 O 3 (ITO), [6][7] Sb-doped SnO 2 (ATO) 8,9 or others [10][11][12][13][14] have attracted growing attention due to their applicability in many optoelectronic applications, such as nearinfrared selective electrochromic devices, 15 (flexible) displays 11 and polymer light emitting diodes. 4 They also demonstrate excellent bio-sensing and chemical sensing capabilities 16 .…”

Section: Introductionmentioning

confidence: 99%

“…18 Extra electrons are introduced by aliovalent donor doping where the impurity atoms in a higher charge state replace some host cations in the lattice. 1 According to the Drude-Lorentz theory, the absorption will increase and resonance peak will shift to higher energies with increasing free charge carrier concentration. 19 The aliovalent doping is therefore expected to result in a reasonably high LSPA in oxide semiconductors at high doping levels when the host oxide becomes a degenerated semiconductor with high extrinsic electrical conductivity.…”

Section: Introductionmentioning

confidence: 99%

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A straightforward and “green” solvothermal synthesis of Al doped zinc oxide plasmonic nanocrystals and piezoresistive elastomer nanocomposite

et al. 2015

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Plasmonic oxide nanocrystals hold great promise in a wide range of applications, for which the availability of scalable and "green" synthesis methods is prerequisite, whereas until recently an excellent response has been demonstrated only for samples prepared through intricate synthesis paths. We report here a simple ethanol solvothermal synthesis route of Al doped ZnO plasmonic nanocrystals (Zn1-xAlxO) at doping levels x up to 0.15. The obtained Al doped ZnO samples consisted of nanoparticles and short nanorods with a diameter around 10 nm at x=0.15 doping level while reaching aspect ratio levels of 50 for lower doping levels. Detailed structural studies by powder X-ray diffraction Rietveld refinement, X-ray absorption and photoelectron spectroscopies show that all samples maintain the structure of phase-pure zincite of space group P63mc. The resulting powders exhibit strong infrared absorption, while remaining largely transparent for visible light, enabling the preparation of transparent colloidal dispersions. Furthermore, as a test of applicability in a practical device, the nanocrystals were used to prepare transparent piezoresistive Zn0.925Al0.075O -polydimethylsiloxane composites. The prepared sensor material exhibits excellent repeatable and reproducible piezoresistive behaviour.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A straightforward and “green” solvothermal synthesis of Al doped zinc oxide plasmonic nanocrystals and piezoresistive elastomer nanocomposite

et al. 2015

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“…An additional way, besides doping, to make ZnO NCs conductive is to photochemically charge them [79]. These NCs have the same optical properties of Al doped ZnO NCs, but show a different chemical reactivity [80]. Manthiram and Alivisatos [38] showed tungsten oxide nanocrystals with potential interest for photo--chemical applications, also owing to their robustness.…”

Section: Methodsmentioning

confidence: 99%

Plasmonics in heavily-doped semiconductor nanocrystals

et al. 2013

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Abstract:Heavily--doped semiconductor nanocrystals characterized by a tunable plasmonic band have been gaining increasing attention recently. Herein, we introduce this type of materials focusing on their structural and photo--physical properties. Beside their continuous--wave plasmonic response, depicted both theoretically and experimentally, we also review recent results on their transient ultrafast response. This was successfully interpreted by adapting models of the ultrafast response of noble metal nanoparticles. IntroductionThe optical features exhibited by metallic nano--systems have been the subject of an intensive theoretical and experimental research, resulting in applications in several fields, from surface--enhanced spectroscopy, to biological and chemical nano--sensing [1]. Such developments are primarily due to the localized surface plasmon resonance (LSPR), which results in intense optical absorption and scattering as well as sub--wavelength localization of large electrical fields in the vicinity of the nano--object [2--10]. The plasmonic response of these metallic nanostructures is strongly dependent on the type of metal of which they are made, on the dielectric function of the surrounding medium, on the particle shape and, even if to a lesser extent, on the particle size. Nanoparticles of several metals, such as Ag, Au, Cu and Pt, exhibiting plasmonic response in the ultraviolet and in the visible regions of the spectrum have been successfully synthesized in the past decades [11--15]. Elongated metallic nanoparticles have been shown to exhibit plasmonic response in the near infrared, due to excitation of the longitudinal plasmon mode [16--18]. It has been recently reported that direct optical excitation of the metal by intense femtosecond laser pulses induces an ultra--fast modulation of the plasmonic resonance, which can be used for ultra--fast modulation of signals [19], paving the way to ultrafast active plasmonics. A quantitative investigation of such dynamical features is therefore crucial for the development of a new generation of ultra--fast nano--devices. Pump--probe spectroscopy, giving access to the electronic excitation and subsequent relaxation processes in the material, is to date the most suitable tool for the experimental study of the ultrafast dynamical features exhibited by plasmonic nanostructures. So far, several noble metal structures have been investigated, including spherical nanoparticles [20--22] and nanorods [23], revealing that the physical processes of excitation and relaxation are actually similar to those observed in bulk (i.e. in thin films) metallic systems, that are the electron--electron, the electron--phonon and the phonon--phonon interactions [24,25].

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“…Since protons provide lower binding energy than Al ions, the photochemically charged NCs are more reactive and, in particular, more susceptible to oxidation. 110 Whitaker et al measured the EPR signal from NCs of different sizes, and compared the various gyromagnetic ratios. In this way they could prove that extra electrons were indeed added to the conduction band of the NCs.…”

Section: 104-107mentioning

confidence: 99%

New materials for tunable plasmonic colloidal nanocrystals

2014

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We present a review on the emerging materials for novel plasmonic colloidal nanocrystals. We start by explaining the basic processes involved in surface plasmon resonances in nanoparticles and then discuss the classes of nanocrystals that to date are particularly promising for tunable plasmonics: nonstoichiometric copper chalcogenides, extrinsically doped metal oxides, oxygen-deficient metal oxides and conductive metal oxides. We additionally introduce other emerging types of plasmonic nanocrystals and finally we give an outlook on nanocrystals of materials that could potentially display interesting plasmonic properties.

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Comparison of extra electrons in colloidal n-type Al3+-doped and photochemically reduced ZnO nanocrystals

Cited by 77 publications

References 21 publications

A straightforward and “green” solvothermal synthesis of Al doped zinc oxide plasmonic nanocrystals and piezoresistive elastomer nanocomposite

A straightforward and “green” solvothermal synthesis of Al doped zinc oxide plasmonic nanocrystals and piezoresistive elastomer nanocomposite

Plasmonics in heavily-doped semiconductor nanocrystals

New materials for tunable plasmonic colloidal nanocrystals

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