Search query: 3 dimension Heterostructure

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abstract: Abstract Photocatalytic hydrogen evolution has emerged as a promising technology to alleviate energy and environmental issues. Numerous inorganic semiconductors have been designed for efficient photocatalytic hydrogen evolution, but which are generally limited by the heavy metal contamination. All organic semiconductors have attracted great interest due to the low cost, stable properties and tunable chemical structures. In our paper, TPA 3CN, with the superior donor acceptor (D A) structure, was synthesized via the molecular engineering of triphenylamine (TPA) and (3 cyano 4,5,5 trimethyl 2(5H) furanylidene) malononitrile (3 CN) Then an all organic TPA 3CN/2D C3N4 heterostructure is formed by linking the TPA 3CN of stronger electron withdrawing property with two dimension graphitic carbon nitride (2D C3N4) which realizes the broader solar absorption compared to the pristine CNS, as well as the quicker electron transfer rate. Significantly, the TPA 3CN/2D C3N4 shows superior photocatalytic performance of 1558.6 mmol (twice as 2D C3N4) under 5 h visible light irradiation (l 400 nm) and its apparent quantum efficiency (AQE) reaches 9.3% at 420 nm. This work offers an innovative opinion for rational development of efficient all organic photocatalysts for solar energy utilization.
author_names: JiaJun Fu

Zhao Mo

Ming Cheng

Fan Chou Xu

Yanhua Song

Xingdong Ding

Zhigang Chen

Hanxiang Chen

Huaming Li

Hui Xu
title: An all organic TPA 3CN/2D C3N4 heterostructure for high efficiency photocatalytic hydrogen evolution
year: 2020

abstract: Intensive efforts have been devoted to the exploration of new optoelectronic devices based on two dimensional transition metal dichalcogenides (TMDCs) owing to their strong light matter interaction and distinctive material properties. In particular, photodetectors featuring both high speed and high responsivity performance are of great interest for a vast number of applications such as high data rate interconnects operated at standardized telecom wavelengths. Yet, the intrinsically small carrier mobilities of TMDCs become a bottleneck for high speed application use. Here, we present high performance vertical van der Waals heterostructure based photodetectors integrated on a silicon photonics platform. Our vertical MoTe 2 graphene heterostructure design minimizes the carrier transit path length in TMDCs and enables a record high measured bandwidth of at least 24 GHz under a moderate bias voltage of 3 V. Applying a higher bias or employing thinner MoTe 2 flakes boosts the bandwidth even to 50 GHz. Simultaneously, our device reaches a high external responsivity of 0.2 A W 1 for incident light at 1,300 nm, benefiting from the integrated waveguide design. Our studies shed light on performance trade offs and present design guidelines for fast and efficient devices. The combination of two diemensional heterostructures and integrated guided wave nano photonics defines an attractive platform to realize high performance optoelectronic devices, such as photodetectors, light emitting devices and electro optic modulators. The low carrier mobilities of TMDCs pose a challenge for applications in high speed photodetection. Integrating vertical two dimensional heterostructures with photonic waveguides allows the intrinsic speed limitations to be overcome and record high photodetection bandwidths to be achieved.
author_names: Nikolaus Flory

Ping Ma

Yannick Salamin

Alexandros Emboras

Takashi Taniguchi

Kenji Watanabe

Juerg Leuthold

Lukas Novotny
title: Waveguide integrated van der Waals heterostructure photodetector at telecom band with high speed and high responsivity
venue: Nature Nanotechnology
year: 2020

abstract: van der Waals heterostructures combining two dimensional magnetic and semiconducting layers constitute a promising platform for interfacing magnetism, electronics, and optics. Here, we use resonant optical reflection spectroscopy to observe the magnetic proximity effect in a gate tunable MoSe_{2}/CrBr_{3} heterostructure. The high quality of the interface leads to a giant zero field splitting of the K and K^ valley excitons in MoSe_{2} equivalent to an external magnetic field of 12 T, with a weak but distinct electric field dependence that hints at potential for electrical control of magnetization. The magnetic proximity effect allows us to use resonant optical spectroscopy to fully characterize the CrBr_{3} magnet, determining the easy axis coercive field, the magnetic anisotropy energy, and critical exponents associated with spin susceptibility and magnetization.
author_names: Livio Ciorciaro

Martin Kroner

Kenji Watanabe

Takashi Taniguchi

Atac Imamoglu
title: Observation of Magnetic Proximity Effect Using Resonant Optical Spectroscopy of an Electrically Tunable MoSe_{2}/CrBr_{3} Heterostructure.
venue: Physical review letters
year: 2020

abstract: Two dimensional material van der Waals (vdW) heterostructures provide an excellent platform for design of novel optoelectronics. In this work, transition metal dichalcogenide WS2 nanodiscs (WS2 NDs) of lateral dimension of 200 400 nm and layer number of 4 7 were synthesized on graphene using a layer by layer, transfer free chemical vapor deposition. On this WS2 NDs/graphene vdW heterostructures, localized surface plasmonic resonance (LSPR) was achieved, resulting in remarkably enhanced light absorption as compared to the counterpart devices with a continuous WS2 layer (WS2 CL/graphene) Remarkably, the photoresponsivity of 6.4 A/W on the WS2 NDs/graphene photodetectors is seven times higher than that (0.91 A/W) of the WS2 CL/graphene vdW heterostructures at an incident 550 nm light intensity of 10 mW/cm2. Furthermore, the WS2 NDs/graphene photodetectors exhibit higher sensitivity to lower lights. Under 550 nm light illumination of 3 mW/cm2, which is beyond the sensitivity limit of the WS2 CL/graphene photodetectors, high photoresponsivity of 8.05 A/W and detectivity of 2.8 x 1010 Jones are achieved at Vsd 5 V. This result demonstrates that the LSPR WS2 NDs/graphene vdW heterostructure is promising for scalable high performance optoelectronics applications.
author_names: Mohammed A Alamri

Maogang Gong

Brent Cook

Ryan Goul

Judy Z Wu
title: Plasmonic WS2 Nanodiscs/Graphene van der Waals Heterostructure Photodetectors.
venue: ACS applied materials interfaces
year: 2019

abstract: Abstract Nickel cobalt layered double hydroxides (NiCo LDHs) nanosheets (NSs) were synthesized on a flexible carbon cloth (CC) substrate by a simple hydrothermal method. Then the manganese dioxide (MnO2) NSs were directly deposited on the NiCo LDH/CC to form three dimensional (3D) self supported core shell MnO2/NiCo LDH/CC flexible electrodes. The MnO2 NSs with three different loading amount on NiCo LDH/CC substrate, named MnO2 1/NiCo LDH/CC, MnO2 2/NiCo LDH/CC and MnO2 3/NiCo LDH/CC, were hydrothermally synthesized in 0.01 M, 0.02 M and 0.03 M potassium permanganate (KMnO4) solution, respectively. The morphology and electrochemical performance of these obtained composite electrodes were observed and analyzed. The MnO2 2/NiCo LDH/CC electrode exhibits a capacitive performance of 312 F g 1 at 0.2 A g 1 (937 mF cm 2 at 1 mV s 1) and maintains 97% of the original capacitance after 5000 charge discharge cycles. The good mechanical stability and excellent cycle performance of MnO2 2/NiCo LDH/CC electrode is benefit from the numerous channels for rapid electron transport provided by the large specific surface area and self supported of NiCo LDH nanoflakes. Therefore, the MnO2 2/NiCo LDH/CC composite electrode is a potential candidate in wearable energy storage device.
author_names: Lianlian Liu

Liang Fang

Fang Wu

Jia Hu

Shu-fang Zhang

Haijun Luo

Bashan Hu

Miao Zhou
title: Self supported core shell heterostructure MnO2/NiCo LDH composite for flexible high performance supercapacitor
year: 2020

abstract: Recently, CO2 reduction to fuels has been the subject of great much numerous studies, but selectivity and activity remain inadequate. Progress has been made on single site two dimensional catalysts based on graphene coupled to a metal and nitrogen for CO2RR but the product is usually CO and the metal N environment remains ambiguous. We report a novel 2D graphene nitrene heterostructure (grafiN6) providing well defined active sites (N6) that can bind 1 to 3 metals for CO2RR. We find that homo bimetallic FeFe grafiN6 could reduce CO2 to CH4 at 0.61 V and to CH3CH2OH at 0.68 V vs RHE, with high product selectivity. Moreover, the heteronuclear FeCu grafiN6 system may be significantly less affected by HER, while maintaining low limiting potential 0.68 V) for C1 and C2 mechanisms. Binding metals to one N6 site but not the other could promote efficient electron transport facilitating some reaction steps. This framework for single multiple metal sites might also provide unique catalytic sites for other catalytic process.
author_names: Shiqiang Chen

Hao Yuan

Sergey I Morozov

Lei Ge

Li Li

Lai Xu

William A Goddard
title: Design of a Graphene Nitrene Two Dimensional Catalyst Heterostructure Providing a Well Defined Site Accommodating 1 to 3 Metals, with Application to CO2 Reduction Electrocatalysis for the 2 Metal Case.
venue: The journal of physical chemistry letters
year: 2020

abstract: In this paper, a two dimensional/two dimensional (2D/2D) heterostructure of Ti3C2/g C3N4 (T/CN) was constructed and used to activate peroxymonosulfate (PMS) for the degradation of diclofenac (DCF) in water in the presence of light illumination. Compared with single photocatalytic process by T/CN (0.040/min) and with pure g C3N4 nanosheets in PMS system (0.071/min) 5.0 and 3.0 times enhanced activities were achieved in the T/CN PMS system at optimum Ti3C2 (1.0 wt% loading under light illumination (0.21/min) Moreover, the decomposing processes of DCF in T/CN PMS system were applicable in a wide initial pH range (3~14) therefore, overcoming the limitation of pH dependence in traditional PMS system. Based on the synergistic effect of photocatalysis and PMS oxidation processes, the 1O2 was generated as primary reactive species for the removal of DCF in T/CN PMS system. The DCF degradation mechanism was further proposed through the results of liquid chromatography mass spectrometry (LC MS) and density functional theory (DFT) calculations.
author_names: Jie He

Jingling Yang

Fengxing Jiang

Peng Liu

Mingshan Zhu
title: Photo assisted peroxymonosulfate activation via 2D/2D heterostructure of Ti3C2/g C3N4 for degradation of diclofenac.
venue: Chemosphere
year: 2020

abstract: Abstract Multi level and multi angle designations of photocatalysts have attracted great attention to address the insufficient photogenerated charge generation and transformation in photocatalysis. In this study, we reported an ultrathin 1D/2D W18O49/g C3N4 nanocomposites with unique multiscale structure and electronic property through direct growth of 1D plasmonic W18O49 nanowires onto the surface of 2D ultrathin g C3N4 nanosheets. Owing to the unique multiscale structure and electronic property, the synthesized nanocomposites present enhanced photocatalytic activity, owns the maximum removal efficiency of 96.3% and rate constant of 0.0464 min 1 for Ibuprofen (IBF) after 60 min under AM 1.5G light. Meanwhile, under near infrared (NIR) light irradiation, the optimum UWN 3 present 39.2% removal efficiency of IBF and the reaction rate reached 0.0027 min 1 after 120 min. Additionally, the degradation pathway indicated that the decarboxylation process was the main decomposition route of IBF in this reaction system, and OH radical species attack process also contributed to the degradation of IBF. Scavenge experiments and mechanism analysis illustrated that IBF degradation in this reaction system mainly depends on h+ O2 and OH radical species, and the promoted photocatalytic performance of the synthesized ultrathin 1D/2D W18O49/g C3N4 nanocomposites are stem from the synergism of the multichannel photogenerated charge transfer pathways. The combination of the multichannel charge transfer pathways mentioned above resulted in the highly efficient photocatalytic activity of the ultrathin 1D/2D W18O49/g C3N4 nanocomposites.
author_names: Yaocheng Deng

Chengyang Feng

Lin Tang

Yaoyu Zhou

Zhaoming Chen

Haopeng Feng

Jiajia Wang

Jiangfang Yu

Yani Liu
title: Ultrathin low dimensional heterostructure composites with superior photocatalytic activity: Insight into the multichannel charge transfer mechanism
year: 2020

abstract: Incommensurate stacking between two different types of two dimensional layered materials furnished the weak interfacial interaction due to the mismatch of their lattice structure, which can be harnessed for development of new generation lubricant additives. Herein, a facile approach is presented to synthesize the ZnO decorated reduced graphene oxide/MoS2 (Gr MS Zn) nanosheets. The Fourier transform infrared, X ray photoelectron spectroscopic, Raman, and transmission electron microscopic analyses confirmed the preparation of Gr MS Zn heterostructure. The MoS2 nanosheets having 3 7 molecular lamellae are thoroughly distributed over the graphene skeleton via weak interfacial interaction. The curved and bent structure of MoS2 nanosheets grown over the graphene lamellae subsidized the cohesive interaction and furnished the stable dispersion of Gr MS Zn in the fully formulated engine oil. The minute dose of Gr MS Zn as a nano additive to engine oil significantly enhanced the tribological performance between the steel steel tribopair by decreasing the friction (37% and the wear volume (87% The microscopic and spectroscopic analyses revealed the formation of a Gr MS Zn based surface protective tribo thin film of low shear strength. The enhanced tribo performance is collectively attributed to (a) uninterrupted supply of ultrathin Gr MS Zn nanosheets to tribo interfaces, (b) stable dispersion of Gr MS Zn, and (c) the significantly low shear strength, arising from weak interfacial interaction between the incommensurately stacked graphene and MoS2 nanosheets.
author_names: Ajay Chouhan

Tarun K Sarkar

Sangita Kumari

Srikanth Vemuluri

Om P Khatri
title: Synergistic lubrication performance by incommensurately stacked ZnO decorated reduced graphene oxide/MoS2 heterostructure.
venue: Journal of colloid and interface science
year: 2020

abstract: The emergence of antibiotic resistant bacteria is the biggest threat to our society. The rapid discovery of drug resistant bacteria is very urgently needed to guide antibiotic treatment development. The current manuscript reports the design of a 2D 0D heterostructure based surface enhanced Raman spectroscopy (SERS) platform, which has the capability for the rapid identification of the multidrug resistant strain of Salmonella DT104. Details of the synthesis and characterization of the heterostructure SERS platform using a two dimensional (2D) WS2 transition metal dichalcogenide (TMD) and zero dimensional (0D) plasmonic gold nanoparticles (GNPs) have been reported. The current manuscript reveals that the 2D 0D heterostructure based SERS platform exhibits extremely high Raman enhancement capabilities. Using Rh 6G and 4 ATP probe molecules, we determined that the SERS sensitivity is in the range of ~10 10 to 10 11 M, several orders of magnitude higher than 2D TMD on its own (10 3 M) or 0D GNPs on their own ~10 6 to 10 7 M) Experimental and theoretical finite difference time domain (FDTD) simulation data indicate that the synergistic effect of an electromagnetic mechanism (EM) and a chemical mechanism (CM) on the heterostructure is responsible for the excellent SERS enhancement observed. Notably, the experimental data reported here show that the heterostructure based SERS has the ability to separate a multidrug resistance strain from a normal strain of Salmonella by monitoring the antibiotic pathogen interaction within 90 minutes, even at a concentration of 100 CFU mL 1.
author_names: Avijit Pramanik

Shamily Patibandla

Salma Begum

Kaelin Gates

Ye Gao

Paresh Chandra Ray
title: A WS2 gold nanoparticle heterostructure based novel SERS platform for the rapid identification of antibiotic resistant pathogens
year: 2020