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ACS Appl Mater Interfaces ; 11(47): 44413-44420, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31691552


Two-dimensional materials have been extensively investigated in the fields of electrochemical sensors, field-effect transistors, and other electronic devices due to their large surface areas, high compatibility with device integration, and so on. Conventional electrodes, such as precious metal layers that are deposited on polymer or silicon wafers, have gradually revealed increasing difficulties in adapting to various device structures, especially for two-dimensional materials, which prefer high exposure of surface atoms. Here, we demonstrate a tailorable metal-ceramic (Cu-TiC0.5) layered structure as novel electrodes with high mechanical property and conductivity and fabricate a highly sensitive gas sensor with graphene lying on this proposed electrodes. The Cu-TiC0.5 layered structure exhibits remarkably high tensile yield strength and compressive yield strength, which increase 7 and 8 times than those of the pure copper, respectively. Meanwhile, excellent flexibility and conductivity could also be obtained with the further thinning of the Cu-TiC0.5 layered composite, which shows its potential applications in flexible electronics. Finally, we demonstrated that a graphene-based gas sensor fabricated on tailored metal-ceramic electrodes was ultrasensitive and robust, which benefits from the good thermal conductivity and peculiar gas channels etched on the surface of copper alloy electrodes.

Chem Commun (Camb) ; 52(7): 1369-72, 2016 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-26616404


We demonstrate the first systematic study of the diameter-dependent photoelectrochemical performance of single silicon nanowires within a broad size range from 200 to 2000 nm. SiNWs with a diameter of 1415 nm exhibit the highest solar energy conversion efficiency, which can be mainly traced to their diameter-dependent light absorption properties.

Técnicas Eletroquímicas/métodos , Nanofios , Processos Fotoquímicos , Silício/química
Phys Chem Chem Phys ; 17(12): 8182-6, 2015 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-25728709


The role of MoS2 as an effective interfacial layer in graphene/silicon solar cells is systematically investigated by varying MoS2 film annealing temperature and thickness. It is found that the power conversion efficiency (PCE) is increased by ∼100% from ∼2.3% to ∼4.4% with 80 °C annealed MoS2 film whereas it drops significantly to ∼0.6% with 200 °C annealed MoS2 film. The results are well explained based on the device energy band diagram. That is, the incorporation of MoS2(80) films leads to the formation of type II structure, facilitating hole transport; while valence band mismatch is formed with MoS2(200) films due to the increase in the work function of MoS2. Besides, the PCE increases gradually with decreasing MoS2 film thickness, and "saturates" at about 2 nm. The PCE can be further enhanced to ∼6.6% with the aid of silicon surface passivation. Our work demonstrates that MoS2 is an excellent interfacial layer to improve the PCE with low-temperature annealing (80 °C in air), which may be helpful in developing efficient and low-cost G/Si solar cells.

Phys Chem Chem Phys ; 17(6): 4757-62, 2015 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-25589409


The hydrothermal growth of ZnO nanorods on graphene draws a specific interest for the advantages of low-temperature processability over a large area and low cost, but challenges still remain in directly growing uniform ZnO seed layers on pristine graphene without impairing its beneficial properties. In this work, the direct growth of ZnO seed layers on graphene via H2O-based atomic layer deposition (ALD) has been investigated. It is found that uniform ZnO thin films can be deposited on graphene via ALD using a combination of single-layer graphene/Cu stacks as substrates and a facile pre-H2O treatment process. After growing ZnO nanorods on graphene, its photovoltaic application in a Cu2ZnSn(SxSe1-x)4 (CZTSSe) solar cell is demonstrated. The performance of graphene-based cells approaches that of ITO-based cells with similar architectures, highlighting that graphene is a potential replacement for ITO in optoelectronic devices. The method reported herein for fabricating ZnO nanorods on graphene using ALD-ZnO as seed layers preserves its properties, and is thus applicable to a wide variety of graphene-based nanoelectronic devices.

Chem Commun (Camb) ; 51(16): 3383-6, 2015 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-25622299


We quantitatively investigated excitons' decaying pathways of photon-excited SiNW arrays to determine the reason for their low performances. It is demonstrated that excitons decay through both carriers' separation and energy transfer due to Si's indirect-band-gap feature, and these two pathways could be regulated through surface modification.

ACS Appl Mater Interfaces ; 6(12): 9742-50, 2014 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-24865360


Photoelectrochemical (PEC) water splitting to produce H2 is a renewable method for addressing the worldwide energy consumption increasing and fossil fuels storage shrinking. In order to achieve sustainable PEC H2 production, the semiconductor electrodes should have good photo-absorption ability, proper band positions, and chemical stability in aqueous condition. Different from the large-band-gap semiconductors such as TiO2, which can work efficiently under UV light, Si is an narrow-band-gap semiconductor that can efficiently absorb visible light; however, Si is indirect semiconductor and susceptible to photocorrosion in aqueous solution. In this paper, we demonstrate a new strategy of first protecting and then activating to develop a stable visible light photoanode for photoelectrochemical hydrogen production. This AgNPs/PEDOT/SiNW arrays show an encouraging solar-to-chemical energy conversion efficiency of 2.86 % and a pronounced incident photo-to-current conversion efficiency (IPCE) across the whole visible region. Our strategy proposed here contributes to further improvement of corrosion protection and solar energy harvesting for narrow-band-gap semiconductors that employed in visible light photoelectrochemical and photoelectric conversion applications.