Selective detection of physisorbed hydrocarbons using photothermal cantilever deflection spectroscopy

Bagheri, Mehrdad; Chae, Inseok; Lee, Dongkyu; Kim, Seonghwan; Thundat, Thomas

doi:10.1016/j.snb.2013.10.078

Cited by 25 publications

(20 citation statements)

References 20 publications

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“…Another advantage of the technique is that it works for physisorbed molecules, making sensor regeneration at room temperature easy. 9,10,8 The sensitivity of detection in the nanomechanical spectroscopic technique depends on the thermal mass of the sensor. Therefore, lowering the thermal mass of the detector could result in superior sensitivity in chemical sensing.…”

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confidence: 99%

Photothermal Electrical Resonance Spectroscopy of Physisorbed Molecules on a Nanowire Resonator

2015

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Mid-infrared (IR) photothermal spectroscopy of adsorbed molecules is an ideal technique for molecular recognition in miniature sensors with very small thermal mass. Here, we report on combining the photothermal spectroscopy with electrical resonance of a semiconductor nanowire for enhanced sensitivity, selectivity, and simplified readout. Wide band gap semiconductor bismuth ferrite nanowire, by virtue of its very low thermal mass and abundance of surface states in the band gap, facilitates thermally induced charge carrier trapping in the surface states, which affects its electrical resonance response. Electrical resonance response of the nanowire varies significantly depending on the photothermal spectrum of the adsorbed molecules. We demonstrate highly selective detection of mid-IR photothermal spectral signatures of femtogram level molecules physisorbed on a nanowire by monitoring internal dissipation response at its electrical resonance.

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confidence: 99%

Photothermal Electrical Resonance Spectroscopy of Physisorbed Molecules on a Nanowire Resonator

2015

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“…Conventional IR detection is based on the Beer-Lambert principle, which depends on the ratio of the intensities of scattered (or transmitted) photons and the incident photons, whereas the PCDS detection mechanism relies on the heat generated during the photon absorption process. Therefore, based on the relaxation process, the peak intensities between the PCDS and conventional IR absorption can be different [11,15]. However, the peak positions (wavelength) show excellent agreement between the PCDS and conventional techniques.…”

Section: Nanomechanical Ir Absorption Spectrummentioning

confidence: 99%

“…It should be noted that only molecules having a dipole moment can be IR active. Fourier Transform infrared spectroscopy (FTIR) is a routinely used technique based on vibrational spectroscopy which shows the molecular finger print of the material being investigated [15]. Both conventional IR spectroscopy and FTIR rely on the Beer-Lambert principle, which relates the absorption of light to the properties of the material through which the light is traveling.…”

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confidence: 99%

Methane sensing at room temperature using photothermal cantilever deflection spectroscopy

Rahimi

Chae

Hawk

et al. 2015

Sensors and Actuators B: Chemical

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“…One of the most under exploited properties of a cantilever sensor is its extremely high sensitivity to temperature variation when it is fabricated as a bi-material beam. This extreme high thermomechanical sensitivity of a bi-material cantilever can be exploited for measuring the extremely small thermal changes due to nonradiative decay of molecular vibrations of the adsorbed molecules [14][15][16][17][18][19][20][21][22][23][24][25]. The molecular vibrations of the adsorbed molecules can be resonantly excited by illuminating using infrared (IR) light.…”

Section: Molecular Adsorption-induced Cantilever Deflection Approachmentioning

confidence: 99%

Photothermal cantilever deflection spectroscopy

2014

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Microcantilever sensors offer high sensitivity in the detection of adsorbed molecules based either on resonance frequency shift or changes in cantilever deflection, as both of these signals can be detected with very high resolution. Despite the high sensitivity offered by this platform, cantilevers suffer from poor selectivity due to the lack of sufficiently selective interfacial layers which can be immobilized on cantilever surfaces. This problem can be overcome by using photothermal cantilever deflection spectroscopy (PCDS), which exploits the high thermomechanical sensitivity of bi-material microcantilevers. A bi-material cantilever responds to heat generated by the nonradiative decay process when the adsorbed molecules are resonantly excited with infrared (IR) light. The variation in the cantilever deflection as a function of illuminating IR wavelength corresponds to the conventional IR absorption spectrum of the adsorbed molecules. In addition, the mass of the adsorbed molecules can be determined by measuring the resonance frequency shift of the cantilever as an orthogonal signal for the quantitative analysis. This multi-modal PCDS offers unprecedented opportunities for obtaining very high selectivity in chemical and biological sensing without using selective interfacial layers or extrinsic labels.

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Selective detection of physisorbed hydrocarbons using photothermal cantilever deflection spectroscopy

Cited by 25 publications

References 20 publications

Photothermal Electrical Resonance Spectroscopy of Physisorbed Molecules on a Nanowire Resonator

Photothermal Electrical Resonance Spectroscopy of Physisorbed Molecules on a Nanowire Resonator

Methane sensing at room temperature using photothermal cantilever deflection spectroscopy

Photothermal cantilever deflection spectroscopy

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