The Experts below are selected from a list of 1284 Experts worldwide ranked by ideXlab platform

Antoine Kahn - One of the best experts on this subject based on the ideXlab platform.

  • High-Work-Function Molybdenum Oxide Hole Extraction Contacts in Hybrid Organic–Inorganic Perovskite Solar Cells
    2016
    Co-Authors: Philip Schulz, Jan Tiepelt, Jeffrey A Christians, Igal Levine, Eran Edri, Erin M Sanehira, Gary Hodes, David Cahen, Antoine Kahn
    Abstract:

    We investigate the effect of high work function contacts in halide perovskite absorber-based photovoltaic devices. Photoemission spectroscopy measurements reveal that band bending is induced in the absorber by the deposition of the high work function Molybdenum Trioxide (MoO3). We find that direct contact between MoO3 and the perovskite leads to a chemical reaction, which diminishes device functionality. Introducing an ultrathin spiro-MeOTAD buffer layer prevents the reaction, yet the altered evolution of the energy levels in the methylammonium lead iodide (MAPbI3) layer at the interface still negatively impacts device performance

  • effect of contamination on the electronic structure and hole injection properties of moo3 organic semiconductor interfaces
    Applied Physics Letters, 2010
    Co-Authors: Jens Meyer, Michael Kroger, Antoine Kahn
    Abstract:

    The electronic structure and hole-injection properties of ambient contaminated Molybdenum Trioxide (MoO3) surfaces are studied by ultraviolet and inverse photoemission spectroscopy, and current-voltage measurements. Contamination reduces the work function (WF), electron affinity (EA) and ionization energy by about 1 eV with respect to the freshly evaporated film, to values of 5.7 eV, 5.5 eV, and 8.6 eV, respectively. However, the WF and EA remain sufficiently large that the hole-injection properties of MoO3 are not affected by contamination. The results are of particular importance in view of potential applications of transition metal oxides for low-cost manufacturing of devices in low-vacuum or nonvacuum environment.

  • role of the deep lying electronic states of moo3 in the enhancement of hole injection in organic thin films
    Applied Physics Letters, 2009
    Co-Authors: Michael Kroger, Sami Hamwi, Jens Meyer, Thomas Riedl, Wolfgang Kowalsky, Antoine Kahn
    Abstract:

    The electronic structures of vacuum-deposited Molybdenum Trioxide (MoO3) and of a typical MoO3/hole transport material (HTM) interface are determined via ultraviolet and inverse photoelectron spectroscopy. Electron affinity and ionization energy of MoO3 are found to be 6.7 and 9.68 eV, more than 4 eV larger than generally assumed, leading to a revised interpretation of the role of MoO3 in hole injection in organic devices. The MoO3 films are strongly n-type. The electronic structure of the oxide/HTM interface shows that hole injection proceeds via electron extraction from the HTM highest occupied molecular orbital through the low-lying conduction band of MoO3.

  • p type doping of organic wide band gap materials by transition metal oxides a case study on Molybdenum Trioxide
    Organic Electronics, 2009
    Co-Authors: Michael Kroger, Sami Hamwi, Jens Meyer, Thomas Riedl, Wolfgang Kowalsky, Antoine Kahn
    Abstract:

    A study on p-doping of organic wide band gap materials with Molybdenum Trioxide using current transport measurements, ultraviolet photoelectron spectroscopy and inverse photoelectron spectroscopy is presented. When MoO3 is co-evaporated with 4,4 0 -Bis(N-carbazolyl)-1,1 0-biphenyl (CBP), a significant increase in conductivity is observed, compared to intrinsic CBP thin films. This increase in conductivity is due to electron transfer from the highest occupied molecular orbital of the host molecules to very low lying unfilled states of embedded Mo3O9 clusters. The energy levels of these clusters are estimated by the energy levels of a neat MoO3 thin film with a work function of 6.86 eV, an electron affinity of 6.7 eV and an ionization energy of 9.68 eV. The Fermi level of MoO3-doped CBP and N,N 0

  • p type doping of organic wide band gap materials by transition metal oxides a case study on Molybdenum Trioxide
    Organic Electronics, 2009
    Co-Authors: Michael Kroger, Sami Hamwi, Jens Meyer, Thomas Riedl, Wolfgang Kowalsky, Antoine Kahn
    Abstract:

    Abstract A study on p-doping of organic wide band gap materials with Molybdenum Trioxide using current transport measurements, ultraviolet photoelectron spectroscopy and inverse photoelectron spectroscopy is presented. When MoO3 is co-evaporated with 4,4′-Bis(N-carbazolyl)-1,1′-biphenyl (CBP), a significant increase in conductivity is observed, compared to intrinsic CBP thin films. This increase in conductivity is due to electron transfer from the highest occupied molecular orbital of the host molecules to very low lying unfilled states of embedded Mo3O9 clusters. The energy levels of these clusters are estimated by the energy levels of a neat MoO3 thin film with a work function of 6.86 eV, an electron affinity of 6.7 eV and an ionization energy of 9.68 eV. The Fermi level of MoO3-doped CBP and N,N′-bis(1-naphtyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (α-NPD) thin films rapidly shifts with increasing doping concentration towards the occupied states. Pinning of the Fermi level several 100 meV above the HOMO edge is observed for doping concentrations higher than 2 mol% and is explained in terms of a Gaussian density of HOMO states. We determine a relatively low dopant activation of ∼0.5%, which is due to Coulomb-trapping of hole carriers at the ionized dopant sites.

Philip Schulz - One of the best experts on this subject based on the ideXlab platform.

  • high work function Molybdenum oxide hole extraction contacts in hybrid organic inorganic perovskite solar cells
    ACS Applied Materials & Interfaces, 2016
    Co-Authors: Philip Schulz, Jan Tiepelt, Jeffrey A Christians, Igal Levine, Eran Edri, Erin M Sanehira, Gary Hodes, David Cahen
    Abstract:

    We investigate the effect of high work function contacts in halide perovskite absorber-based photovoltaic devices. Photoemission spectroscopy measurements reveal that band bending is induced in the absorber by the deposition of the high work function Molybdenum Trioxide (MoO3). We find that direct contact between MoO3 and the perovskite leads to a chemical reaction, which diminishes device functionality. Introducing an ultrathin spiro-MeOTAD buffer layer prevents the reaction, yet the altered evolution of the energy levels in the methylammonium lead iodide (MAPbI3) layer at the interface still negatively impacts device performance.

  • High-Work-Function Molybdenum Oxide Hole Extraction Contacts in Hybrid Organic–Inorganic Perovskite Solar Cells
    2016
    Co-Authors: Philip Schulz, Jan Tiepelt, Jeffrey A Christians, Igal Levine, Eran Edri, Erin M Sanehira, Gary Hodes, David Cahen, Antoine Kahn
    Abstract:

    We investigate the effect of high work function contacts in halide perovskite absorber-based photovoltaic devices. Photoemission spectroscopy measurements reveal that band bending is induced in the absorber by the deposition of the high work function Molybdenum Trioxide (MoO3). We find that direct contact between MoO3 and the perovskite leads to a chemical reaction, which diminishes device functionality. Introducing an ultrathin spiro-MeOTAD buffer layer prevents the reaction, yet the altered evolution of the energy levels in the methylammonium lead iodide (MAPbI3) layer at the interface still negatively impacts device performance

David Cahen - One of the best experts on this subject based on the ideXlab platform.

  • high work function Molybdenum oxide hole extraction contacts in hybrid organic inorganic perovskite solar cells
    ACS Applied Materials & Interfaces, 2016
    Co-Authors: Philip Schulz, Jan Tiepelt, Jeffrey A Christians, Igal Levine, Eran Edri, Erin M Sanehira, Gary Hodes, David Cahen
    Abstract:

    We investigate the effect of high work function contacts in halide perovskite absorber-based photovoltaic devices. Photoemission spectroscopy measurements reveal that band bending is induced in the absorber by the deposition of the high work function Molybdenum Trioxide (MoO3). We find that direct contact between MoO3 and the perovskite leads to a chemical reaction, which diminishes device functionality. Introducing an ultrathin spiro-MeOTAD buffer layer prevents the reaction, yet the altered evolution of the energy levels in the methylammonium lead iodide (MAPbI3) layer at the interface still negatively impacts device performance.

  • High-Work-Function Molybdenum Oxide Hole Extraction Contacts in Hybrid Organic–Inorganic Perovskite Solar Cells
    2016
    Co-Authors: Philip Schulz, Jan Tiepelt, Jeffrey A Christians, Igal Levine, Eran Edri, Erin M Sanehira, Gary Hodes, David Cahen, Antoine Kahn
    Abstract:

    We investigate the effect of high work function contacts in halide perovskite absorber-based photovoltaic devices. Photoemission spectroscopy measurements reveal that band bending is induced in the absorber by the deposition of the high work function Molybdenum Trioxide (MoO3). We find that direct contact between MoO3 and the perovskite leads to a chemical reaction, which diminishes device functionality. Introducing an ultrathin spiro-MeOTAD buffer layer prevents the reaction, yet the altered evolution of the energy levels in the methylammonium lead iodide (MAPbI3) layer at the interface still negatively impacts device performance

Katsuaki Suganuma - One of the best experts on this subject based on the ideXlab platform.

  • growth and extension of one step sol gel derived Molybdenum Trioxide nanorods via controlling citric acid decomposition rate
    Crystal Growth & Design, 2015
    Co-Authors: Shuren Cong, Tohru Sugahara, Yukiko Hirose, Shijo Nagao, Katsuaki Suganuma
    Abstract:

    A simple sol–gel solution route for the synthesis of α-phase Molybdenum Trioxide (α-MoO3) nanorods is investigated in terms of growth mechanism with controlling the citric acid decomposition rate. The single-phase and single-crystal nanorod arrays of MoO3 grown in random directions from a silica glass substrate had mean diameters and lengths of 10 and 500 nm, respectively, as determined through chemical analysis. The citric acid plays a critical role for the nanorods growth process from investigating the relative molar ratio of molybdate and citric acid in the precursor. Moreover, the dissociation timing of the citric acid, which was controlled by the other two synthesis parameters, i.e., sintering time and solvents, also greatly influences growth and phase transition of the MoO3 nanorods, which was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The synthesis parameters were optimized to design the length and density of the nanorod arrays. The longest nanorods can be obtained ...

  • Growth and Extension of One-Step Sol–Gel Derived Molybdenum Trioxide Nanorods via Controlling Citric Acid Decomposition Rate
    2015
    Co-Authors: Shuren Cong, Tohru Sugahara, Yukiko Hirose, Shijo Nagao, Tingting Wei, Jinting Jiu, Katsuaki Suganuma
    Abstract:

    A simple sol–gel solution route for the synthesis of α-phase Molybdenum Trioxide (α-MoO3) nanorods is investigated in terms of growth mechanism with controlling the citric acid decomposition rate. The single-phase and single-crystal nanorod arrays of MoO3 grown in random directions from a silica glass substrate had mean diameters and lengths of 10 and 500 nm, respectively, as determined through chemical analysis. The citric acid plays a critical role for the nanorods growth process from investigating the relative molar ratio of molybdate and citric acid in the precursor. Moreover, the dissociation timing of the citric acid, which was controlled by the other two synthesis parameters, i.e., sintering time and solvents, also greatly influences growth and phase transition of the MoO3 nanorods, which was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The synthesis parameters were optimized to design the length and density of the nanorod arrays. The longest nanorods can be obtained up to 600 nm using a dimethylacetamide solvent, a molar ratio of Mo:citric acid = 0.5:1.5, and sintering at 673 K for 15 min in an ambient atmosphere. Findings of the present study describe that the factors of the nanorods’ growth and phase changing are deeply correlated with disassemble steps of the Mo metal–citric acid complex in the sol–gel precursor solution, which may contribute to applying the material development in several electronic devices using MoO3 nanostructures

Erin M Sanehira - One of the best experts on this subject based on the ideXlab platform.

  • high work function Molybdenum oxide hole extraction contacts in hybrid organic inorganic perovskite solar cells
    ACS Applied Materials & Interfaces, 2016
    Co-Authors: Philip Schulz, Jan Tiepelt, Jeffrey A Christians, Igal Levine, Eran Edri, Erin M Sanehira, Gary Hodes, David Cahen
    Abstract:

    We investigate the effect of high work function contacts in halide perovskite absorber-based photovoltaic devices. Photoemission spectroscopy measurements reveal that band bending is induced in the absorber by the deposition of the high work function Molybdenum Trioxide (MoO3). We find that direct contact between MoO3 and the perovskite leads to a chemical reaction, which diminishes device functionality. Introducing an ultrathin spiro-MeOTAD buffer layer prevents the reaction, yet the altered evolution of the energy levels in the methylammonium lead iodide (MAPbI3) layer at the interface still negatively impacts device performance.

  • High-Work-Function Molybdenum Oxide Hole Extraction Contacts in Hybrid Organic–Inorganic Perovskite Solar Cells
    2016
    Co-Authors: Philip Schulz, Jan Tiepelt, Jeffrey A Christians, Igal Levine, Eran Edri, Erin M Sanehira, Gary Hodes, David Cahen, Antoine Kahn
    Abstract:

    We investigate the effect of high work function contacts in halide perovskite absorber-based photovoltaic devices. Photoemission spectroscopy measurements reveal that band bending is induced in the absorber by the deposition of the high work function Molybdenum Trioxide (MoO3). We find that direct contact between MoO3 and the perovskite leads to a chemical reaction, which diminishes device functionality. Introducing an ultrathin spiro-MeOTAD buffer layer prevents the reaction, yet the altered evolution of the energy levels in the methylammonium lead iodide (MAPbI3) layer at the interface still negatively impacts device performance