Publications by Anna Krammer | EPFL Graph Search

Infrared and conductive properties of TCO films deposited by magnetron sputtering at different temperatures

Low-emissive Transparent Conductive Oxide (TCO) coatings, such as Indium Tin Oxide (ITO) films, can be used to reduce radiative losses that affect Hybrid photovoltaic-thermal (PV-T) devices. This work shows the optical properties of ITO deposited by magnet ...

EDP Sciences2024

Development of novel orange colored photovoltaic modules with improved angular stability and high energy efficiency

Andreas Schueler, Anna Krammer, Maxime Lagier, Jérémy Jacques Antonin Fleury

This work illustrates a novel approach for the development of orange multilayer interference coatings with improved angular stability of color while maximizing energy efficiency. The high energy efficiency of these interference coatings is based on thin fi ...

2024

Synergistic interactions between PtRu catalyst and nitrogen-doped carbon support boost hydrogen oxidation

Andreas Schueler, Jeremy Luterbacher, Xile Hu, Anna Krammer, Weiyan Ni, Lichen Bai, Miyeon Chang, Seunghwa Lee, Songlan Sun, Seongmin Jin, Yiwei Zheng

Hydroxide exchange membrane fuel cell (HEMFC) is a potentially cost-effective energy conversion technology. However, current state-of-the-art HEMFCs require a high loading of platinum-group-metal (PGM) catalysts, especially for the hydrogen oxidation react ...

NATURE PORTFOLIO2023

Electrical control of glass-like dynamics in vanadium dioxide for data storage and processing

Andras Kis, Andreas Schueler, Anna Krammer, Elison de Nazareth Matioli, Reza Soleiman Zadeh Ardebili, Mohammad Samizadeh Nikooytabalvandani, Philip Johannes Walter Moll, Guilherme Migliato Marega

Metal–oxide–semiconductor junctions are the building blocks of modern electronics and can provide a variety of functionalities, from memory to computing. The technology, however, faces constraints in terms of further miniaturization and compatibility with ...

2022

Electronic Regulation of Nickel Single Atoms by Confined Nickel Nanoparticles for Energy-Efficient CO2 Electroreduction

Andreas Schueler, Xile Hu, Anna Krammer, Wenhao Ren

Modulating the electronic structure of atomically dispersed active sites is promising to boost catalytic activity but is challenging to achieve. Here we show a cooperative Ni single-atom-on-nanoparticle catalyst (NiSA/NP) prepared via direct solid-state py ...

Wiley-VCH Verlag GmbH2022

An efficient nickel hydrogen oxidation catalyst for hydroxide exchange membrane fuel cells

Andreas Schueler, Jeremy Luterbacher, Xile Hu, Anna Krammer, Florent Emmanuel Héroguel, Weiyan Ni, Liang Yao, Seunghwa Lee

Hydroxide exchange membrane fuel cells are promising as an energy conversion technology, but require platinum group metal electrocatalysts for their application. A Ni-based hydrogen oxidation reaction catalyst is now shown to exhibit unprecedented electroc ...

2022

VO2:Ge based thermochromic solar absorber coatings

Josef Andreas Schuler, Anna Krammer

Flat plate solar collectors face the problem of overheating and the ensuing high thermal stresses and general collector damage lead to high maintenance costs. To address this challenge, absorber coatings with a passive optical switch at critically high ope ...

ELSEVIER2022

In-line electronic and structural characterization of reactively sputtered Cu-Co-Mn black spinel oxides

Andreas Schueler, Anna Krammer, Maxime Lagier

Cu-Co-Mn spinel oxide thin films are deposited by reactive magnetron sputtering. The x-ray diffraction (XRD) spectrum suggests a nanocrystalline spinel film when sputtered at approximate to 465 degrees C. In-line scanning tunneling microscopy confirms nano ...

A V S AMER INST PHYSICS2021

Ug-value and edge heat loss of triple glazed insulating glass units:A comparison between measured and declared values

Andreas Schueler, Anna Krammer

Triple glazed low-e coated insulating glass units with argon filling of five different suppliers on the European market with a declared thermal transmittance in the undisturbed centre of glass (Ug-value) of 0.6 W/m(2)K have been purchased from resellers an ...

ELSEVIER2021

Strong coloration of nanoporous tungsten oxides by in-vacuo lithiation for all-solid-state electrochromic devices

Andreas Schueler, Olivia Valérie Charlotte Bouvard, Luc Burnier, Anna Krammer, Maxime Lagier

Electrochromic windows allow for an improved management of solar heat gains in buildings and enhanced visual comfort of building users. All-solid-state electrochromic devices can be especially durable. During their fabrication lithium has to be inserted, p ...

ELSEVIER SCIENCE SA2021

Co-Sputtered Monocrystalline GeSn for Infrared Photodetection

Andreas Schueler, Josef Andreas Schuler, Anna Fontcuberta i Morral, Luc Burnier, Nicolas Philippe Laurent Humblot, Anna Krammer, Andrea Giunto

We demonstrate monocrystalline growth of GeSn on Ge and Si substrates by co-sputtering. We discuss the evolution of film growth with thickness, elucidating the effects of substrate temperature, sputtering source, and the importance of hydrogen dilution in ...

IEEE2020

Thermochromic solar absorber coatings with elevated transition temperature

Anna Krammer

Due to their simple design and operation, solar thermal collectors for domestic hot water gener-ation and space heating are one of the most common solar energy harvesting systems in use today. Dur-ing cold periods all the absorbed energy is useful. During ...

EPFL2020

Radio-Frequency Characteristics of Ge-doped Vanadium Dioxide Thin Films with Increased Transition Temperature

Igor Stolichnov, Mihai Adrian Ionescu, Andreas Schueler, Teodor Rosca, Anna Krammer, Riyaz Mohammed Abdul Khadar, Matteo Cavalieri, Fatemeh Qaderi Rahaqi, Andrei Müller

This work investigates and reports on the radio-frequency (RF) behavior in the frequency range of 5 – 35 GHz of germanium-doped (Ge-doped VO2) vanadium dioxide thin films, deposited on silicon substrates via sputtering and pulsed laser deposition (PLD) wit ...

2020

A Novel Reconfigurable CMOS Compatible Ka Band Bandstop Structure Using Split-Ring Resonators and Vanadium Dioxide (VO2) Phase Change Switches

Mihai Adrian Ionescu, Andreas Schueler, Emanuele Andrea Casu, Junrui Zhang, Anna Krammer, Riyaz Mohammed Abdul Khadar, Andrei Müller

The article presents the design, fabrication and characterization of a novel complementary metal-oxidesemiconductor (CMOS) compatible reconfigurable Ka band bandstop structure using split ring resonators (SRR) while employing the Vanadium Dioxide (VO2) pha ...

IEEE2019

In-situ and post annealing effect on the microstructure and the optical properties of black Cu-Co-Mn oxide spinel coating for Parabolic Trough Collector (PTC) applications

Andreas Schueler, Josef Andreas Schuler, Anna Krammer, Samaneh Daviran

The present paper deals with the deposition of Cu-Co-Mn oxides thin film by magnetron sputtering to produce a black selective coating for solar Parabolic Trough Collector (PTC) systems. The effect of temperature was studied between the nominal temperature ...

IOP Science2019

Millimeter-wave-triggering of insulator-to-metal transition in Vanadium dioxide

Anja Skrivervik, Mihai Adrian Ionescu, Andreas Schueler, Anna Krammer, Fatemeh Qaderi Rahaqi, Andrei Müller

We establish insulator-to-metal transition (IMT) in Vanadium dioxide (VO2) by millimeter-wave (mm-wave) actuation, using two coupled dipole antennas: a simple one as a continuous mm-wave-source and the other one with an embedded VO2 part as an absorber. We ...

IEEE2019

Predicting the thermal performance of thermochromic flat plate solar collectors

Andreas Schueler, Josef Andreas Schuler, Anna Krammer

A thermochromic vanadium dioxide (VO2) based absorber coating is proposed. The optical response of the multilayered absorber is first simulated, then, the spectral reflectance of the deposited absorber is measured. The determined solar absorptance and ther ...

IOP Science2019

Ni3N as an Active Hydrogen Oxidation Reaction Catalyst in Alkaline Medium

Andreas Schueler, Josef Andreas Schuler, Xile Hu, Anna Krammer, Weiyan Ni

Hydroxide-exchange membrane fuel cells can potentially utilize platinum-group-metal (PGM)-free electrocatalysts, offering cost and scalability advantages over more developed proton-exchange membrane fuel cells. However, there is a lack of non-precious elec ...

Wiley-VCH Verlag GmbH2019

3D Smith charts scattering parameters frequency-dependent orientation analysis and complex-scalar multi-parameter characterization applied to Peano reconfigurable vanadium dioxide inductors

Mihai Adrian Ionescu, Andreas Schueler, Josef Andreas Schuler, Montserrat Fernandez-Bolanos Badia, Emanuele Andrea Casu, Junrui Zhang, Anna Krammer, Matteo Cavalieri, Andrei Müller

Recently, the field of Metal-Insulator-Transition (MIT) materials has emerged as an unconventional solution for novel energy efficient electronic functions, such as steep slope subthermionic switches, neuromorphic hardware, reconfigurable radiofrequency fu ...

Nature Research2019

MoS2/VO2 vdW heterojunction devices: Tunable rectifiers, photodiodes and field effect transistors

Mihai Adrian Ionescu, Andreas Schueler, Olivier Martin, Arnaud Magrez, Chen Yan, Emanuele Andrea Casu, Nicolò Oliva, Anna Krammer

In this work we report a new class of ultra-thin film devices based on n-n van der Waals (vdW) heteroj unctions of MoS2 and VO2, which show remarkable tunable characteristics. The favorable band alignment combined with the sharp and clean vdW interface det ...

2018