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Laser interaction with materials for thin film deposition: From fundamentals to functional films

English title Laser interaction with materials for thin film deposition: From fundamentals to functional films
Applicant Lippert Thomas
Number 172708
Funding scheme Project funding (Div. I-III)
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Material Sciences
Start/End 01.08.2017 - 31.07.2021
Approved amount 514'104.00
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Keywords (6)

photo catalysis; micro-batteries; oxide thin films; plasma properties; oxynitrides; PLD

Lay Summary (German)

Lead
Dieses Forschungsprojekt beruht auf der Herstellung dünner Filme mittels gepulster Laserverdampfung (PLD). Für viele Materialien ist PLD eine der am weitesten verbreiteten Herstellungstechniken für dünne Filme. Diese Filme sind oft ein sehr wichtiger Bestandteil von Bauelementen (elektrisch, optisch) in angewandten Anwendungsfeldern als auch für Grundlagenforschung. Oft können Filme als Modelsysteme hergenommen werden um spezifische Eigenschaften zu studieren, die an konventionellen Proben schwierig zu messen sind. Im Rahmen dieses Projektes betrachten wir zum einen grundlegende Ablationsprozesse um besser das Leistungsvermögen aber auch die Limitationen von PLD zu verstehen. Auf der anderen Seite wollen wir aus Materialen Filme herstellen die von potentiellem Interesse für die sogenannte künstliche Photosynthese sind. Also Materialien, die Licht benutzen um z.B. Wasserstoff als umweltfreundlichen Treibstoff herzustellen, um daraus wiederum elektrische Energie zu gewinnen.
Lay summary

Dieses Projekt ist in zwei Teilprojekte unterteilt:

Im Teilprojekt 1) werden die grundlegenden Ablationsprozesse studiert die wichtig sind um dünne Filme herzustellen. Eine der wichtigsten offenen Fragen ist, wie der Ablationsprozess die chemische Zusammensetzung des Ausgangsmaterials im Film verändert. Weiterhin haben wir nach wie vor kein fundiertes Verständnis des Zusammenwirkens verschiedenster Ablationsparameter auf die Eigenschaften der Filme. Ein grundlegenderes Verständnis der Möglichkeiten und Grenzen des Ablationsprozesses ist daher notwendig um PLD auf eine rationale Basis zu stellen, die es erlaubt zuverlässiger und vorhersagbarer Filme mit einer komplexen Zusammensetzung und gewünschten Eigenschaften herzustellen.

Im Teilprojekt 2 konzentrieren wir uns auf eine spezielle Klasse von halbleitenden Materialien, sogenannte Oxinitride, die als dünne Filme dargestellt und untersucht werden sollen. Die optischen und elektrischen Eigenschaften dieser Materialien sind sehr attraktiv für Anwendungen im Bereich der solaren Wasserspaltung, wobei der sichtbare Bereich des optischen Spektrums verwendet wird. Fragestellungen die gezielt mit solchen Filmen untersucht werden sollen sind die Korrelation zwischen Effizienz und Kristallinität und die Rolle der Probenoberfläche bei der Wasserspaltung. Die Oberfläche, d.h. die Grenzfläche zwischen Halbleiter und Wasser ist genau der Bereich, in dem die elektro-chemischen Reaktionen stattfinden. Die wohldefinierte Herstellung und Charakterisierung von Oberflächen bzw. Grenzflächen wird daher ein sehr wichtiges Werkzeug für das Verständnis für solare Wasserspaltung sein. Die Ergebnisse dieses Teilprojektes werden auch wichtig für ein zukünftiges, rationales Design neuer Oxinitride mit verbesserter Effizienz sein.

Direct link to Lay Summary Last update: 25.04.2017

Lay Summary (English)

Lead
This research project is based on the fabrication of thin films by pulsed laser deposition (PLD). PLD is among the most widespread deposition method for the growth of thin films of many different materials. This films are often essential part of devices and find many applications in Applied Science. They can also be used for fundamental investigation for they represent ideal model system to probe properties of materials that are difficult to investigate with standard samples. Here we address on one side the fundamentals of the PLD process to get more insights into its potentials and limitations. On the other side, we tackle the fabrication as thin films of materials of interest for the so-called artificial photosynthesis, i.e. the use solar light to generate hydrogen that can then be used as a clean fuel to produce electric energy.
Lay summary

This research project is divided into two sub-projects 1) and 2).

In Sub-project 1) we will investigate the fundamental process of laser ablation to fabricate thin films of different materials. One of the most important open problems is for example the often observed different composition and therefore properties of the deposited thin films as compared to the starting materials, which is caused by various process parameter. Along the same line, we do not have a thorough description of the influence of several inter-correlated experimental parameters on the physical and chemical properties of the film. Despite the widespread use of this technology for thin film deposition of a variety of different materials successful and unsuccessful results are often not supported by a clear understanding of ablation process itself.  A deeper understanding of capabilities and limits of the ablation process will allow a much more reliable and rational application of this technique.

In Sub-project 2) we focus a specific class of semiconductor materials called oxynitrides. This materials offer very appealing optical and electronic properties for application in solar water splitting. This films allows the investigations of their performance as a function of the sample crystallinity and, more importantly, as a function of the sample surface. The surface, or better the interface between the semiconductor and water, is exactly where the electrochemical reaction able to split the water molecules takes place. Well-defined surfaces/interfaces can be obtained with thin films which become for this reason invaluable tools to understand the solar water splitting process. The outcome of this sub-project will help the rational design of new oxynitride materials with improved performance.  

Direct link to Lay Summary Last update: 25.04.2017

Responsible applicant and co-applicants

Employees

Publications

Publication
Systematic Material Study Reveals TiNb 2 O 7 as a Model Wide‐Bandgap Photoanode Material for Solar Water Splitting
Burns Eric. W., Pergolesi Daniele, Schmidt Thomas J., Lippert Thomas, Daramalla Venkateswarlu (2020), Systematic Material Study Reveals TiNb 2 O 7 as a Model Wide‐Bandgap Photoanode Material for Solar Water Splitting, in Chemistry – A European Journal, 26(31), 7065-7073.
Improved Photoelectrochemical Water Splitting of CaNbO 2 N Photoanodes by CoPi Photodeposition and Surface Passivation
Haydous Fatima, Si Wenping, Guzenko Vitaliy A., Waag Friedrich, Pomjakushina Ekaterina, El Kazzi Mario, Sévery Laurent, Wokaun Alexander, Pergolesi Daniele, Lippert Thomas (2018), Improved Photoelectrochemical Water Splitting of CaNbO 2 N Photoanodes by CoPi Photodeposition and Surface Passivation, in The Journal of Physical Chemistry C, 123(2), 1059-1068.
Oxynitride Thin Films versus Particle-Based Photoanodes: A Comparative Study for Photoelectrochemical Solar Water Splitting
Haydous Fatima, Döbeli Max, Si Wenping, Waag Friedrich, Li Fei, Pomjakushina Ekaterina, Wokaun Alexander, Gökce Bilal, Pergolesi Daniele, Lippert Thomas (2018), Oxynitride Thin Films versus Particle-Based Photoanodes: A Comparative Study for Photoelectrochemical Solar Water Splitting, in ACS Applied Energy Materials, 2(1), 754-763.

Associated projects

Number Title Start Funding scheme
180181 Highly efficient solar H2 production by photo-biocatalytic water splitting 01.10.2018 Bilateral programmes
159198 The search for low temperature super protonic conductivity 01.09.2015 Project funding (Div. I-III)
147190 Influence of Strain and Interfaces on the Properties of Ion Conducting Thin Films for micro-Solid-Oxide-Fuel-Cells 01.05.2013 Project funding (Div. I-III)
152553 Positive or negative? Selecting the charge state of ions during pulsed laser deposition of thin films 01.07.2014 Project funding (Div. I-III)
142176 Small band-gap nanostructured perovskite materials for photovoltaic and photocatalytic hydrogen generation applications 01.01.2013 Romanian-Swiss Research Programme (RSRP)
147190 Influence of Strain and Interfaces on the Properties of Ion Conducting Thin Films for micro-Solid-Oxide-Fuel-Cells 01.05.2013 Project funding (Div. I-III)

Abstract

At the heart of this project are fundamental properties of thin films growth (mainly oxides) using pulsed laser ablation leading to the development of functional films. These films will partly be incorporated into device structures. The project is divided into two independent sub-projects: Fundamentals of Pulsed Laser Deposition and Thin Films Oxynitride Photocatalysts. The two sub-projects are interrelated with each other, assuring that the involved PhD students can benefit from their cooperations. 1.The sub-project Fundamentals of Pulsed Laser Deposition is aimed at an improved understanding of thin film deposition by pulsed laser deposition, to have a better control over the desired structural and physical properties. The project will be mainly focussed on the composition, structure, and quality of thin films. All of these aspects are strongly influenced by the process parameter and the laser induced plasma properties. 2.The sub-project Thin Films Oxynitride Photocatalysts aims at the growth and characterization of oxynitride thin films use for solar water splitting application. In the solar water splitting process the energy of the light from the sun is converted into chemical energy by generating hydrogen gas which can then be used as a fuel. The interest in oxynitride thin films is in a better fundamental understanding of this class of materials with promising properties.
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