Photoactivated Mixed In-Plane and Edge-Enriched p-Type MoS<sub>2</sub> Flake-Based NO<sub>2</sub> Sensor Working at Room Temperature

Agrawal, Abhay V.; Kumar, Rahul; Venkatesan, Swaminathan; Zakhidov, Alex; Yang, Guang; Bao, Jiming; Kumar, Mahesh; Kumar, Mukesh

doi:10.1021/acssensors.8b00146

Cited by 168 publications

(89 citation statements)

References 40 publications

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“…[ 37 ] Therefore, it is quite difficult to grow p‐type MoS 2 directly by CVD; moreover, from a gas‐sensing point of view, it would be interesting to investigate the properties of p‐type MoS 2 because it has been only rarely reported. [ 39 ] Recently, we succeed to synthesize few layers of p‐type MoS 2 by spin coating of a molybdenum acid peroxide sol–gel precursor (including 1% W) followed by sulfurization at 900 °C; more details are shown in our previous article. [ 40 ] The optical and AFM images ( Figure a,b) demonstrate the successful preparation of large‐area continuous films with a thickness of ≈3.5 nm.…”

Section: Resultsmentioning

confidence: 99%

“…The sensing mechanism of pure MoS 2 gas sensor (either n‐type or p‐type) has been well interpreted by the surface reaction with the target gases, which causes the changes in the resistance of the MoS 2 due to the charge transfer between the adsorbate and the support. [ 18,39 ] However, the sensing mechanism of our MoS 2 p–n junction sensor needs to be further studied. When n‐type MoS 2 and p‐type MoS 2 are brought into contact ( Figure a), the electrons are expected to transfer from the n‐type MoS 2 to p‐type MoS 2 , leaving a positive area on the surface of MoS 2 and forming a depletion layer; similarly, the holes near the interface of the p–n junction move from p‐type MoS 2 to n‐type MoS 2 , forming a negative charge area.…”

Section: Resultsmentioning

confidence: 99%

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MoS₂ Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO₂ Sensor

Zheng

et al. 2020

Adv Funct Materials

232

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Van der Waals p-n junctions of 2D materials present great potential for electronic devices due to the fascinating properties at the junction interface. In this work, an efficient gas sensor based on planar 2D van der Waals junctions is reported by stacking n-type and p-type atomically thin MoS 2 films, which are synthesized by chemical vapor deposition (CVD) and soft-chemistry route, respectively. The electrical conductivity of the van der Waals p-n junctions is found to be strongly affected by the exposure to NO 2 at room temperature (RT). The MoS 2 p-n junction sensor exhibits an outstanding sensitivity and selectivity to NO 2 at RT, which are unavailable in sensors based on individual n-type or p-type MoS 2 . The sensitivity of 20 ppm NO 2 is improved by 60 times compared to a p-type MoS 2 sensor, and an extremely low limit of detection of 8 ppb is obtained under ultraviolet irradiation. Complete and very fast sensor recovery is achieved within 30 s. These results are superior to most of the previous reports related to NO 2 detection. This work establishes an entirely new sensing platform and proves the feasibility of using such materials for the high-performance detection of gaseous molecules at RT.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

MoS₂ Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO₂ Sensor

Zheng

et al. 2020

Adv Funct Materials

232

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“…Generally, the pyrite‐type transition metal disulfide (FeS 2 ) with abundant S 2 2− ions show fast electrical transport and have employed as promising catalysts for electrocatalytic reactions,78–82 but the lack of basic active sites limited their intrinsic activity 83–88. Besides, metal chalcogenides can also be made into various heterostructures and nanocomposites, which show enhanced catalysis in electrochemical reactions ( Figure ) 96–116…”

Section: Introductionmentioning

confidence: 99%

Optimized Metal Chalcogenides for Boosting Water Splitting

et al. 2020

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splitting (2H 2 O → 2H 2 + O 2 ), consisting of hydrogen evolution and oxygen evolution reaction (HER/OER), can convert electricity to chemical energy in H 2 and O 2 for further energy applications. The practical application of overall water splitting, however, is still limited due to the lack of effective and stable catalysts to reduce reaction energy barrier and enhance Faraday efficient for both reactions. [6][7][8][9][10] Different materials have been studied for overall water splitting catalysis, like metal chalcogenides, metal carbides, oxides, etc. The transition metal carbides, especially graphene, have a better electroconductivity, ductility, and high surface area which display excellent performance in water splitting. [11][12][13] Oxides as another abundant species on the earth also show better water splitting performance, but their stability in hard media is not very good. [14][15][16] The layered double hydroxides (LDH) with unique structure, abundant interstratified electrons and channels for intermediate adsorption and desorption display wonderful water splitting performance. [17][18][19][20] Additionally, the metalorganic frameworks (MOFs) and their based nanocrystals as newly nanomaterials have got much attention in various fields, but their structure limited the active sites exposure for the complete coordinative metal sites. [21][22][23][24][25] Therefore, it is important to enable the cost-effective, large-scale production of these catalysts, and further improve the performance and efficiency of overall water splitting.Transition metal chalcogenides have many different compositions with various lattice structure, while those materials also have unique electronic structures. [26] Based on those superior properties, the transition metal chalcogenides show promising application in many energy applications, [27] such as electrochemical catalysis, photocatalysis, metal-air batteries, and other energy conversion reactions. Especially for their abundant defects sties, [26][27][28] tunable electronic structure, [29][30][31][32] and various morphology, [33][34][35][36][37] the transition metal chalcogenides exhibit boosting performance for water splitting. However, they still have some disadvantages, such as poor conductivity, activity, and stability, in water splitting limited their large-scale industrial application. [38][39][40][41][42] How to synthesize the active and stable transition metal chalcogenides is still a big challenge for wide application. In this Review, the several promising strategies are designed to prepare the active and stable transition metal chalcogenides (Scheme 1). → 2H 2 + O 2 ) is a very promising avenue to effectively and environmentally friendly produce highly pure hydrogen (H 2 ) and oxygen (O 2 ) at a large scale. Different materials have been developed to enhance the efficiency for water splitting. Among them, chalcogenides with unique atomic arrangement and high electronic transport show interesting catalytic properties in various electrochemical reactions, such as the ...

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“…Photodetectors based on few‐layered MoS 2 have exhibited outstanding photodetection properties, such as having a high photogain up to 13.3 and a fast photoresponse time of 70 µs . Recently, Kumar and co‐workers reported an edge‐enriched MoS 2 ‐based photoactivated probe that had a fast photoresponse NO 2 detection . Morpurgo and co‐workers also demonstrated that a monolayer of MoS 2 exhibited a maximum conductivity with suitable sulfur vacancies that was favorable for photogenerated hole‐trapping .…”

Section: Introductionmentioning

confidence: 99%

Edge‐Enriched Ultrathin MoS₂ Embedded Yolk‐Shell TiO₂ with Boosted Charge Transfer for Superior Photocatalytic H₂ Evolution

Wang

Zhu

Cao

et al. 2019

Adv Funct Materials

139

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Exploring TiO 2 -photocatalysts for sunlight conversion has high demand in artificial photosynthesis. In this work, edge-enriched ultrathin molybdenum disulfide (MoS 2 ) flakes are uniformly embedded into the bulk of yolk-shell TiO 2 as a cocatalyst to accelerate photogeneratedelectron transfer from the bulk to the surface of TiO 2 . The as-formed MoS 2 /TiO 2 (0.14 wt%) hybrids exhibit a high hydrogen evolution rate (HER) of 2443 μmol g −1 h −1 , about 1000% and 470% of that of pristine TiO 2 (247 μmol g −1 h −1 ) and bulk MoS 2 decorated TiO 2 (513 μmol g −1 h −1 ). Such a greatly enhanced HER is attributed to the exposed catalytic edges of the ultrathin MoS 2 flakes with a robust chemical linkage (TiS bond), providing rapid charge transfer channels between TiO 2 and MoS 2 . The catalytic stability is promoted by the antiaggregation of the highly dispersed MoS 2 flakes in the bulk of yolk-shell TiO 2 . The exponential fitted decay kinetics of time-resolved photoluminescence (ns-PL) spectra illustrates that embedding ultrathin MoS 2 flakes in TiO 2 effectively decreases the average lifetime of PL in the MoS 2 /TiO 2 hybrids (τ ave = 4.55 ns), faster than that of pristine TiO 2 (≈7.17 ns) and the bulk MoS 2 /TiO 2 (≈6.13 ns), allowing a superior charge separation and charge trapping process for reducing water.

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Photoactivated Mixed In-Plane and Edge-Enriched p-Type MoS₂ Flake-Based NO₂ Sensor Working at Room Temperature

Cited by 168 publications

References 40 publications

MoS₂ Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO₂ Sensor

MoS₂ Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO₂ Sensor

Optimized Metal Chalcogenides for Boosting Water Splitting

Edge‐Enriched Ultrathin MoS₂ Embedded Yolk‐Shell TiO₂ with Boosted Charge Transfer for Superior Photocatalytic H₂ Evolution

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Photoactivated Mixed In-Plane and Edge-Enriched p-Type MoS2 Flake-Based NO2 Sensor Working at Room Temperature

Cited by 168 publications

References 40 publications

MoS2 Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO2 Sensor

MoS2 Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO2 Sensor

Optimized Metal Chalcogenides for Boosting Water Splitting

Edge‐Enriched Ultrathin MoS2 Embedded Yolk‐Shell TiO2 with Boosted Charge Transfer for Superior Photocatalytic H2 Evolution

Contact Info

Product

Resources

About

Photoactivated Mixed In-Plane and Edge-Enriched p-Type MoS₂ Flake-Based NO₂ Sensor Working at Room Temperature

MoS₂ Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO₂ Sensor

MoS₂ Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO₂ Sensor

Edge‐Enriched Ultrathin MoS₂ Embedded Yolk‐Shell TiO₂ with Boosted Charge Transfer for Superior Photocatalytic H₂ Evolution