Steinbach, Claudia

Schmid, Alexander

Nenning, Andreas

Fahrnberger, Florian

Hutter, Herbert

Kubicek, Markus

Fleig, Jürgen

2025-01-09T14:31:51Z

2025-01-09T14:31:51Z

2024-07-18

<div class="csl-bib-body"> <div class="csl-entry">Steinbach, C., Schmid, A., Nenning, A., Fahrnberger, F., Hutter, H., Kubicek, M., &#38; Fleig, J. (2024, July 18). <i>Prediction of space charges at SrTiO3|mixed ionic and electronic oxide heterojunctions from defect chemistry</i> [Conference Presentation]. 24th International conference on solid state ionics, London, United Kingdom of Great Britain and Northern Ireland (the).</div> </div>

http://hdl.handle.net/20.500.12708/208260

Solid oxide cells are promising devices for decarbonizing the energy economy, as they offer efficient energy storage and generate green alternatives to fossil fuels. In such electrochemical cells, the interfaces between various components are vital for the charge transfer kinetics and therefore for the overall performance of the cell. Although there are well-established models describing interfacial space charge regions for either electronic or ionic species, models describing space charge regions for both ionic and electronic charge carriers are far less developed. The latter type of space charge is, for example, present in high temperature solid oxide solar cells based on the interfaces between SrTiO3 (STO) and other mixed ionic and electronic conductors (MIECs) [1]. Experiments yield photovoltages up to > 1 V, but the interplay of ionic and electronic defects in determining the corresponding space charge potential is not truly understood. This work focuses on the investigation of space charge regions between highly electronic conducting MIECs and STO. YBa2Cu3O7-δ (YBCO), La0.6Sr0.4FeO3-δ (LSF), La0.6Sr0.4CoO3-δ (LSC), La0.65Sr0.35MnO3-δ (LSM) and La0.9Sr0.1CrO3-δ (LSCr) thin films were grown by pulsed laser deposition on (nominally) undoped STO single crystals. The resulting interfacial space charge zones are investigated by several approaches: First and most prominently, the resistances of space charge regions at the MIEC│MIEC interfaces were determined in a broad range of oxygen partial pressures at 500°C by means of electrochemical impedance spectroscopy. According to these measurements, investigated materials are distinguishable into MIECs leading to very pronounced space charges (LSM, LSCr), MIECs with moderate space charges (LSF, LSC), and oxides that do not lead to any measurable space charge resistance (YBCO). Interestingly, experiments of nanometer thin interlayers of LSM revealed that already a layer thickness of a single unit cell leads to the formation of a space charge with properties very similar to much thicker films. In a second approach, 18O tracer diffusion across the corresponding interfaces revealed information on the depletion of ionic defects (oxygen vacancies). Third, work function measurements by means of X-ray photoelectron spectroscopy were performed for LSCr, LSM and LSF layers on STO, which strongly support the space charge data obtained from impedance measurements. The same is true for the fourth approach, the analysis of space charges by means of photovoltages measured upon UV illumination of these MIEC│STO hetero-interfaces [1]. Finally, a model is developed, which correlates the ionic and electronic driving forces determining the space charge potentials. This model predicts a relation between space charge potentials and reducibilities of the MIECs, i.e. the transition points in Brouwer diagrams. Comparison with literature data on defect energies indeed confirms the predicted trends. [1] Morgenbesser, M.; Schmid, A.; Viernstein, A.; de Dios Sirvent, J.; Chiabrera, F.; Bodenmüller, N.; Taibl, S.; Kubicek, M.; Baiutti, F.; Tarancon, A.; Fleig, J. SrTiO3 based high temperature solid oxide solar cells: Photovoltages, photocurrents and mechanistic insight. Solid State Ionics 2021, 368, 115700.

en

space charge

SrTiO3

impedance measurements

Prediction of space charges at SrTiO3|mixed ionic and electronic oxide heterojunctions from defect chemistry

Presentation

Vortrag

Conference Presentation

M1

Surfaces and Interfaces

100

E164 - Institut für Chemische Technologien und Analytik

0000-0002-9610-8205

0000-0002-4457-4730

0000-0001-9313-3731

0009-0006-7060-6691

0000-0001-6623-9805

0000-0002-8401-6717

24th International conference on solid state ionics

15-07-2024

19-07-2024

On Site

Event for scientific audience

London

GB

Steinbach, Claudia

Chemie

1040

100

http://purl.org/coar/resource_type/c_18cp

conference paper not in proceedings

Publications

no Fulltext

en

none

E164-04-3 - Forschungsgruppe Festkörperionik

E164-04-3 - Forschungsgruppe Festkörperionik

E164-04-3 - Forschungsgruppe Festkörperionik

E164-01-2 - Forschungsgruppe Oberflächen-, Spurenanalytik und Chemometrie

E164-01-2 - Forschungsgruppe Oberflächen-, Spurenanalytik und Chemometrie

E164-04-3 - Forschungsgruppe Festkörperionik

E164-04 - Forschungsbereich Technische Elektrochemie

0000-0002-9610-8205

0000-0002-4457-4730

0000-0001-9313-3731

0009-0006-7060-6691

0000-0001-6623-9805

0000-0002-8401-6717

E164-04 - Forschungsbereich Technische Elektrochemie

E164-04 - Forschungsbereich Technische Elektrochemie

E164-04 - Forschungsbereich Technische Elektrochemie

E164-01 - Forschungsbereich Imaging und Instrumentelle Analytische Chemie

E164-01 - Forschungsbereich Imaging und Instrumentelle Analytische Chemie

E164-04 - Forschungsbereich Technische Elektrochemie

E164 - Institut für Chemische Technologien und Analytik