Highly Sensitive Gas Sensor by the LaAlO<sub>3</sub>/SrTiO<sub>3</sub> Heterostructure with Pd Nanoparticle Surface Modulation

Chan, Ngai Yui; Zhao, Meng; Huang, Jianxing; Au, K.; Wong, M.H.; Yao, Hei Man; Lü, Wei; Chen, Yan; Ong, Chung Wo; Chan, Helen Lai Wa; Dai, Jiyan

doi:10.1002/adma.201401597

Cited by 83 publications

(60 citation statements)

References 42 publications

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“…[14][15][16] Catalytic functionalization of the SMO surfaces turns out to be indispensable for the further enhancement of gas sensitivity and selectivity. Catalysts such as Pt, [ 17 ] Pd, [ 18 ] Si, [ 19 ] and graphene [ 20 ] have been synthesized and functionalized on SMO nanostructures with the objective of improving biomarker detection performances. Thus far, diverse SMO-catalyst composite sensing layers have been proposed that use electrospun SMO nanofi brous structures functionalized with different catalytic nanoparticles (NPs) such as Pt-WO 3 hemitubes, [ 21 ] Pt-SnO 2 nanofi bers (NFs), [ 22 ] Pd-SnO 2 NFs, [ 23 ] and catalytic graphene functionalized with WO 3 nanotubes [ 24 ] for the detection of H 2 S and acetone in exhaled breath.…”

Section: Introductionmentioning

confidence: 99%

WO₃ Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates

Choi

Kim

Cho

et al. 2016

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A novel catalyst functionalization method, based on protein-encapsulated metallic nanoparticles (NPs) and their self-assembly on polystyrene (PS) colloid templates, is used to form catalyst-loaded porous WO3 nanofibers (NFs). The metallic NPs, composed of Au, Pd, or Pt, are encapsulated within a protein cage, i.e., apoferritin, to form unagglomerated monodispersed particles with diameters of less than 5 nm. The catalytic NPs maintain their nanoscale size, even following high-temperature heat-treatment during synthesis, which is attributed to the discrete self-assembly of NPs on PS colloid templates. In addition, the PS templates generate open pores on the electrospun WO3 NFs, facilitating gas molecule transport into the sensing layers and promoting active surface reactions. As a result, the Au and Pd NP-loaded porous WO3 NFs show superior sensitivity toward hydrogen sulfide, as evidenced by responses (R(air)/R(gas)) of 11.1 and 43.5 at 350 °C, respectively. These responses represent 1.8- and 7.1-fold improvements compared to that of dense WO3 NFs (R(air)/R(gas) = 6.1). Moreover, Pt NP-loaded porous WO3 NFs exhibit high acetone sensitivity with response of 28.9. These results demonstrate a novel catalyst loading method, in which small NPs are well-dispersed within the pores of WO3 NFs, that is applicable to high sensitivity breath sensors.

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Section: Introductionmentioning

confidence: 99%

WO₃ Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates

Choi

Kim

Cho

et al. 2016

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“…Recently, Dai et al took one step forward to utilize a two-dimensional electron gas at LaAlO 3 /SrTiO 3 interface for fast and selective detection of various oxidizing and reducing gases at room temperature. 43 However, despite presence of previous experimental reports on both CO 2 uptake [19][20][21] and band gap reduction 33,44 on bare SrTiO 3 (001) surfaces, a corresponding CO 2 sensing mechanism is still to be developed. Motivated by this, in this work, we perform a detailed ab initio study of CO 2 adsorption on the most stable SrTiO 3 surfaces.…”

Section: Introductionmentioning

confidence: 99%

Band gap modulation of SrTiO₃ upon CO₂ adsorption

Sopiha

Malyi

Persson

et al. 2017

Phys. Chem. Chem. Phys.

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CO 2 chemisorption on SrTiO 3 (001) surfaces is studied using ab initio calculations in order to establish new chemical sensing mechanisms. We find that CO 2 adsorption opens the material band gap, however, while the adsorption on the TiO 2 -terminated surface neutralizes surface states at the valence band (VB) maximum, CO 2 on the SrO-terminated surfaces suppresses the conduction band (CB) minimum. For the TiO 2 -terminated surface, the effect is explained by the passivation of dangling bonds, whereas for the SrO-terminated surface, the suppression is caused by the surface relaxation. Modulation of the VB states implies a more direct change in charge distribution, and thus the induced change in band gap is more prominent at the TiO 2 termination. Further, we show that both CO 2 adsorption energy and surface band gap are strongly dependent on CO 2 coverage, suggesting that the observed effect can be utilized for sensing application in a wide range of CO 2 concentrations.

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“…The formation of heterostructures based on 2D materials, especially the p-n heterojunctions, has been proven effective to enhance the sensor performance due to the ability to tune the chargec oncentrationa nd modulate the charge transport at the hetero-interfaces. [9] Normally,t he preparation of p-n heterostructures requires at least two steps,s uch as stepwise growth of one type of materialo na nother, layer by layer stacking,a nd post-growth selectivechemical conversion. [10] Yet, the one-step facile preparation of p-n heterostructures based on 2D materials remains achallenge.…”

Section: Introductionmentioning

confidence: 99%

Solution‐Processed p‐SnSe/n‐SnSe₂ Hetero‐Structure Layers for Ultrasensitive NO₂ Detection

Wang

Liu

Dai

et al. 2020

Chemistry A European J

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The formation of semiconductor heterostructures is an effective approach to achieve high performance in electrical gas sensing. However, such heterostructures are usually prepared via multi‐step procedures. In this contribution, by taking advantage of the crystal phase‐dependent electronic property of SnSex based materials, we report a one‐step colloid method for the preparation of SnSe(x%)/SnSe2(100−x%) p–n heterostructures, with x ≈30, 50, and 70. The obtained materials with solution processability were successfully fabricated into NO2 sensors. Among them, the SnSe(50 %)/SnSe2(50 %) based sensor with an active layer thickness of 2 μm exhibited the highest sensitivity to NO2 (30 % at 0.1 ppm) with a limit of detection (LOD) down to 69 ppb at room temperature (25 °C). This was mainly attributed to the formation of p–n junctions that allowed for gas‐induced modification of the junction barriers. Under 405 nm laser illumination, the sensor performance was further enhanced, exhibiting a 3.5 times increased response toward 0.1 ppm NO2, along with a recovery time of 4.6 min.

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Highly Sensitive Gas Sensor by the LaAlO₃/SrTiO₃ Heterostructure with Pd Nanoparticle Surface Modulation

Cited by 83 publications

References 42 publications

WO₃ Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates

WO₃ Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates

Band gap modulation of SrTiO₃ upon CO₂ adsorption

Solution‐Processed p‐SnSe/n‐SnSe₂ Hetero‐Structure Layers for Ultrasensitive NO₂ Detection

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Highly Sensitive Gas Sensor by the LaAlO3/SrTiO3 Heterostructure with Pd Nanoparticle Surface Modulation

Cited by 83 publications

References 42 publications

WO3 Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates

WO3 Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates

Band gap modulation of SrTiO3 upon CO2 adsorption

Solution‐Processed p‐SnSe/n‐SnSe2 Hetero‐Structure Layers for Ultrasensitive NO2 Detection

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Highly Sensitive Gas Sensor by the LaAlO₃/SrTiO₃ Heterostructure with Pd Nanoparticle Surface Modulation

WO₃ Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates

WO₃ Nanofiber-Based Biomarker Detectors Enabled by Protein-Encapsulated Catalyst Self-Assembled on Polystyrene Colloid Templates

Band gap modulation of SrTiO₃ upon CO₂ adsorption

Solution‐Processed p‐SnSe/n‐SnSe₂ Hetero‐Structure Layers for Ultrasensitive NO₂ Detection