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Ma Y.,State Key Laboratory for Mesoscopic Physics | Wang S.,State Key Laboratory for Mesoscopic Physics | Zheng L.,State Key Laboratory for Mesoscopic Physics | Lu Z.,State Key Laboratory for Mesoscopic Physics | And 4 more authors.
Chinese Journal of Chemistry | Year: 2014

For the first time in 2009, the inorganic-organic hybrid perovskite materials were applied in liquid dye-sensitized solar cells. In 2013, the power conversion efficiency successfully reached 15%, followed by great amount of research papers bursting out. Till August 2014, the highest efficiency is certified to 17.9%, and the reported efficiency is even up to 19.3%. They quickly go beyond dye-sensitized solar cells and organic solar cells. It is expected the perovskite has its efficiency same to the single-crystal silicon cells. The game changer of solar cells is coming. The perovskite solar cells are cheap and easily to be made, which will benefit both science and industry. This review summarized recent development of both perovskite materials and solar cell devices, not only including new material developments of perovskite compositions, structures, and fabrication methods, but also focusing on device structures, charge transfer mechanism and stability properties of perovskite solar cells. Their perspective is also estimated. Copyright © 2014 SIOC, CAS, Shanghai & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhou Z.,Shanghai University | Zhou Z.,University of Oxford | Zhou Z.,Aberystwyth University | Zhang Y.,Shanghai University | And 6 more authors.
Lecture Notes in Electrical Engineering | Year: 2013

This paper gives out a theoretical framework of electron/X-ray Huang diffuse scattering intensity at the immediate vicinity of Bragg reflection in reciprocal space. Nodal lines of two types in the simulated patterns of Huang diffuse scattering intensity are discussed in connection with a loop shape factor and the Huang diffuse scattering intensity from infinitesimal loops. It is suggested that the Huang diffuse scattering method is supplementary to the conventional TEM amplitude contrast imaging techniques and it has advantages in characterizing the morphology of very small dislocation loop when other methods fail. © 2013 Springer-Verlag.


Wan Y.,State Key Laboratory for Mesoscopic Physics | Wan Y.,Peking University | Zhang H.,State Key Laboratory for Mesoscopic Physics | Zhang K.,State Key Laboratory for Mesoscopic Physics | And 7 more authors.
ACS Applied Materials and Interfaces | Year: 2016

Monolayer MoS2, with fascinating mechanical, electrical, and optical properties, has generated enormous scientific curiosity and industrial interest. Controllable and scalable synthesis of monolayer MoS2 on various desired substrates has significant meaning in both basic scientific research and device application. Recent years have witnessed many advances in the direct synthesis of single-crystalline MoS2 flakes or their polycrystalline aggregates on numerous diverse substrates, such as SiO2-Si, mica, sapphire, h-BN, and SrTiO3, etc. In this work, we used the dual-temperature-zone atmospheric-pressure chemical vapor deposition method to directly synthesize large-scale monolayer MoS2 on fused silica, the most ordinary transparent insulating material in daily life. We systematically investigated the photoluminescence (PL) properties of monolayer MoS2 on fused silica and SiO2-Si substrates, which have different thermal conductivity coefficients and thermal expansion coefficients. We found that there exists a stronger strain on monolayer MoS2 grown on fused silica, and the strain becomes more obvious as temperature decreases. Moreover, the monolayer MoS2 grown on fused silica exhibits the unique trait of a fractal shape with tortuous edges and has stronger adsorbability. The monolayer MoS2 grown on fused silica may find application in sensing, energy storage, and transparent optoelectronics, etc. © 2016 American Chemical Society.


Yan Y.,State Key Laboratory for Mesoscopic Physics | Liao Z.-M.,State Key Laboratory for Mesoscopic Physics | Ke X.,University of Antwerp | Van Tendeloo G.,University of Antwerp | And 8 more authors.
Nano Letters | Year: 2014

The photothermoelectric effect in topological insulator Bi 2Se3 nanoribbons is studied. The topological surface states are excited to be spin-polarized by circularly polarized light. Because the direction of the electron spin is locked to its momentum for the spin-helical surface states, the photothermoelectric effect is significantly enhanced as the oriented motions of the polarized spins are accelerated by the temperature gradient. The results are explained based on the microscopic mechanisms of a photon induced spin transition from the surface Dirac cone to the bulk conduction band. The as-reported enhanced photothermoelectric effect is expected to have potential applications in a spin-polarized power source. © 2014 American Chemical Society.


Li C.-Z.,State Key Laboratory for Mesoscopic Physics | Li C.-Z.,Peking University | Li J.-G.,State Key Laboratory for Mesoscopic Physics | Li J.-G.,Peking University | And 10 more authors.
ACS Nano | Year: 2016

Cd3As2 is a model material of Dirac semimetal with a linear dispersion relation along all three directions in the momentum space. The unique band structure of Cd3As2 is made with both Dirac and topological properties. It can be driven into a Weyl semimetal by symmetry breaking or a topological insulator by enhancing the spin-orbit coupling. Here we report the temperature and gate voltage-dependent magnetotransport properties of Cd3As2 nanoplates with Fermi level near the Dirac point. The Hall anomaly demonstrates the two-carrier transport accompanied by a transition from n-type to p-type conduction with decreasing temperature. The carrier-type transition is explained by considering the temperature-dependent spin-orbit coupling. The magnetoresistance exhibits a large nonsaturating value up to 2000% at high temperatures, which is ascribed to the electron-hole compensation in the system. Our results are valuable for understanding the experimental observations related to the two-carrier transport in Dirac/Weyl semimetals, such as Na3Bi, ZrTe5, TaAs, NbAs, and HfTe5. © 2016 American Chemical Society.


Yuan X.,State Key Laboratory for Mesoscopic Physics | Wang H.,State Key Laboratory for Mesoscopic Physics | Wang H.,Peking University | Ouyang Q.,State Key Laboratory for Mesoscopic Physics | Ouyang Q.,Peking University
Physical Review Letters | Year: 2011

The negative index of refraction of nonlinear chemical waves has become a recent focus in nonlinear dynamics researches. Theoretical analysis and computer simulations have predicted that the negative index of refraction can occur on the interface between antiwaves and normal waves in a reaction-diffusion (RD) system. However, no experimental evidence has been found so far. In this Letter, we report our experimental design in searching for such a phenomenon in a chlorite-iodide-malonic acid (CIMA) reaction. Our experimental results demonstrate that competition between waves and antiwaves at their interface determines the fate of the wave interaction. The negative index of refraction was only observed when the oscillation frequency of a normal wave is significantly smaller than that of the antiwave. All experimental results were supported by simulations using the Lengyel-Epstein RD model which describes the CIMA reaction-diffusion system. © 2011 American Physical Society.

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