Publications by Sheng Meng | EPFL Graph Search

Electronic Structures and Catalytic Activities of Niobium Oxides as Electrocatalysts in Liquid-Junction Photovoltaic Devices

Ulf Anders Hagfeldt, Sheng Meng, Sining Yun, Hang Liu

Two types of nanosized niobium oxides and their composites, pseudohexagonal Nb2O5 (TT-Nb2O5), monoclinic NbO2 (M-NbO2), and the coexistence of TT-Nb2O5 and M-NbO2 (TT-Nb2O5/M-NbO2), are successfully synthesized through the urea-metal chloride route, and th ...

WILEY-V C H VERLAG GMBH2019

First Principles Design of Dye Molecules with Ullazine Donor for Dye Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Sheng Meng, Yunfei Jiao, Wanli Ma

We design a series of metal-free donor-pi-bridge molecules (denoted VB0-VB4) based on a new donor group-ullazine donor-as sensitizers for dye sensitized solar cell (DSSC) applications. Density functional theory (DFT) and time-dependent DFT calculations rev ...

American Chemical Society2013

Structure-Property Relations in All-Organic Dye-Sensitized Solar Cells

Michael Graetzel, Sheng Meng, Fan Zhang, Yunfei Jiao

A structureproperty relationship in all-organic dye solar cells is revealed by first-principles molecular dynamics and real-time time-dependent density functional theory simulations, accompanied with experimental confirmation. An important structural featu ...

Wiley-Blackwell2013

Bis(pyrazol-1-yl)methane as Non-Chromophoric Ancillary Ligand for Charged Bis-Cyclometalated Iridium(III) Complexes

Michael Graetzel, Mohammad Khaja Nazeeruddin, Davide Di Censo, Rosario Scopelliti, Il Jung, Sheng Meng

New charged cyclometalated iridium(III) complexes Ir(ppy)2(L) [ppy = 2-phenylpyridine; L = bis(pyrazol-1-yl)methane (for 1); L = bis(3,5-dimethylpyrazol-1-yl)methane (for 2)] were synthesized and their electrochemical and photophysical properties st ...

Wiley-Blackwell2012

Theoretical investigation of the C-60/copper phthalocyanine organic photovoltaic heterojunction

Efthimios Kaxiras, Jun Ren, Sheng Meng

Molecular heterojunctions, such as the one based on copper phthalocyanine (CuPc) and carbon fullerene (C-60) molecules, are commonly employed in organic photovoltaic cells as electron donor-acceptor pairs. We have investigated the different atomic structur ...

2012

Design of Dye Acceptors for Photovoltaics from First-Principles Calculations

Michael Graetzel, Mohammad Khaja Nazeeruddin, Efthimios Kaxiras, Sheng Meng

We investigate a set of donor-pi-acceptor (D-pi-A) dyes with new acceptor groups for dye-sensitized solar cells, using time-dependent density-functional-theory calculations of the electronic structure and optical absorption. We considered three types of mo ...

American Chemical Society2011

D-pi-A Dye System Containing Cyano-Benzoic Acid as Anchoring Group for Dye-Sensitized Solar Cells

Michael Graetzel, Guido Rothenberger, Shaik Mohammed Zakeeruddin, Robin Humphry-Baker, Takeru Bessho, Efthimios Kaxiras, Sheng Meng

A D-pi-A dye (KM-1) incorporating cyanobenzoic acid as a new acceptor/anchoring group has been synthesized for dye-sensitized solar cells (DSCs) with a high molar extinction coefficient of 66 700 M-1 cm(-1) at 437 nm. Theoretical calculations show that the ...

American Chemical Society2011

Properties of copper (fluoro-)phthalocyanine layers deposited on epitaxial graphene

Efthimios Kaxiras, Jun Ren, Sheng Meng

We investigate the atomic structure and electronic properties of monolayers of copper phthalocyanines (CuPc) deposited on epitaxial graphene substrate. We focus in particular on hexadecafluorophthalocyanine (F16CuPc), using both theoretical and experimenta ...

American Institute of Physics2011

Electron and Hole Dynamics in Dye-Sensitized Solar Cells: Influencing Factors and Systematic Trends

Efthimios Kaxiras, Sheng Meng

We investigate electron and hole dynamics upon photon excitation in dye-sensitized solar cells, using a recently developed method based on real-time evolution of electronic states through time-dependent density functional theory. The systems we considered ...

American Chemical Society (ACS)2010

Optical properties of clusters and molecules from real-time time-dependent density functional theory using a self-consistent field

Efthimios Kaxiras, Jun Ren, Sheng Meng

We present a detailed study of optical absorption spectra of finite-size structures, using a method based on time-dependent density-functional theory (TDDFT), which involves a self-consistent field for the propagation of the Kohn-Sham wavefunctions in real ...

Taylor & Francis2010

Selective adsorption and electronic interaction of F16CuPc on epitaxial graphene

Efthimios Kaxiras, Jun Ren, Sheng Meng, Xi Chen

We investigate the electronic coupling between copper hexadecafluoro-phthalocyanine (F16CuPc) and epitaxial graphene (EG) on 6H-SiC (0001) using a combined approach of low-temperature scanning tunneling spectroscopy and electronic structure calculations. T ...

2010

Topological Frustration in Graphene Nanoflakes: Magnetic Order and Spin Logic Devices

Oleg Yazyev, Efthimios Kaxiras, Sheng Meng

Magnetic order in graphene-related structures can arise from size effects or from topological frustration. We introduce a rigorous classification scheme for the types of finite graphene structures (nanoflakes) which lead to large net spin or to antiferroma ...

2009

Comment on graphene nanoflakes with large spin: Broken-symmetry states

Oleg Yazyev, Efthimios Kaxiras, Sheng Meng

American Chemical Society (ACS)2008