Significantly improved measurement accuracy in determining the thermal expansion coefficient of single layer graphene

We have investigated Raman spectra of the G and 2D lines of a single-layer graphene (SLG) with metallic contacts. The shift of the G and 2D lines is correlated to two different factors. Before performing annealing treatment or annealing under low temperature, the electron transfer on graphene surface is dominated by nonuniform strain effect. As the annealing treatment is enhanced, however, a suitable annealing treatment can eliminate the nonuniform strain effect where the relative work function (WF) between graphene and metal becomes a main factor to determine electronic transfer. Moreover, it is confirmed that the optimized annealing treatment can also decrease effectively the structural defect and induced disorder in graphene due to metallic contacts.

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Hybrid dye sensitized solar cell based on single layer graphene quantum dots

Dyes and Pigments ◽

10.1016/j.dyepig.2019.108118 ◽

2020 ◽

Vol 175 ◽

pp. 108118 ◽

Cited By ~ 3

Author(s):

Farhad Jahantigh ◽

S.M. Bagher Ghorashi ◽

Amir Bayat

Keyword(s):

Quantum Dots ◽

Solar Cell ◽

Graphene Quantum Dots ◽

Single Layer ◽

Single Layer Graphene ◽

Dye Sensitized Solar Cell ◽

Dye Sensitized ◽

Layer Graphene

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Out-of-Plane Thermal Expansion Coefficient and Biaxial Young’s Modulus of Sputtered ITO Thin Films

Coatings ◽

10.3390/coatings11020153 ◽

2021 ◽

Vol 11 (2) ◽

pp. 153

Author(s):

Chuen-Lin Tien ◽

Tsai-Wei Lin

Keyword(s):

Thin Films ◽

Thermal Expansion ◽

Thermal Stress ◽

Young’S Modulus ◽

Thermal Expansion Coefficient ◽

Expansion Coefficient ◽

Young's Modulus ◽

Heating Temperature ◽

Glass Substrates ◽

Ito Thin Films

This paper proposes a measuring apparatus and method for simultaneous determination of the thermal expansion coefficient and biaxial Young’s modulus of indium tin oxide (ITO) thin films. ITO thin films simultaneously coated on N-BK7 and S-TIM35 glass substrates were prepared by direct current (DC) magnetron sputtering deposition. The thermo-mechanical parameters of ITO thin films were investigated experimentally. Thermal stress in sputtered ITO films was evaluated by an improved Twyman–Green interferometer associated with wavelet transform at different temperatures. When the heating temperature increased from 30 °C to 100 °C, the tensile thermal stress of ITO thin films increased. The increase in substrate temperature led to the decrease of total residual stress deposited on two glass substrates. A linear relationship between the thermal stress and substrate heating temperature was found. The thermal expansion coefficient and biaxial Young’s modulus of the films were measured by the double substrate method. The results show that the out of plane thermal expansion coefficient and biaxial Young’s modulus of the ITO film were 5.81 × 10−6 °C−1 and 475 GPa.

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Millisecond lattice gasification for high-density CO2- and O2-sieving nanopores in single-layer graphene

Science Advances ◽

10.1126/sciadv.abf0116 ◽

2021 ◽

Vol 7 (9) ◽

pp. eabf0116

Author(s):

Shiqi Huang ◽

Shaoxian Li ◽

Luis Francisco Villalobos ◽

Mostapha Dakhchoune ◽

Marina Micari ◽

...

Keyword(s):

Single Layer ◽

High Density ◽

Single Layer Graphene ◽

Pore Density ◽

Vacancy Defects ◽

Carbon Gasification ◽

Layer Graphene ◽

Gas Molecules ◽

Good Agreement

Etching single-layer graphene to incorporate a high pore density with sub-angstrom precision in molecular differentiation is critical to realize the promising high-flux separation of similar-sized gas molecules, e.g., CO2 from N2. However, rapid etching kinetics needed to achieve the high pore density is challenging to control for such precision. Here, we report a millisecond carbon gasification chemistry incorporating high density (>1012 cm−2) of functional oxygen clusters that then evolve in CO2-sieving vacancy defects under controlled and predictable gasification conditions. A statistical distribution of nanopore lattice isomers is observed, in good agreement with the theoretical solution to the isomer cataloging problem. The gasification technique is scalable, and a centimeter-scale membrane is demonstrated. Last, molecular cutoff could be adjusted by 0.1 Å by in situ expansion of the vacancy defects in an O2 atmosphere. Large CO2 and O2 permeances (>10,000 and 1000 GPU, respectively) are demonstrated accompanying attractive CO2/N2 and O2/N2 selectivities.

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