Photovoltages in perovskite-type oxide thin film cells Introduction Mechanistic Investigation for LSCr10/STO Conclusion Maximilian Morgenbesser(a)*, Alexander Viernstein(a), Niklas Bodenmüller(a), Stefanie Taibl(a), Markus Kubicek(a), Jürgen Fleig(a) (a) TU Wien, Institute of Chemical Technologies and Analytics, Vienna, Austria Contact Information maximilian.morgenbesser@tuwien.ac.at TU Wien - Institute of Chemical Technologies and Analytics Getreidemarkt 9 – 1060 Vienna, Austria References Current and Voltage Measurements for LSCr10/STO Material Optimization Experimental SrTiO3 (STO), a perovskite-type oxide, shows many interesting effects under UV light illumination, such as an increase in oxygen incorporation rate,1 an enhancement in conductivity and a change in color in Fe doped STO single crystals.2 The increased oxygen uptake under UV light has also been used for a battery-type voltage in STO under UV light irradiation.3 With a top layer, e.g. (La,Sr)CrO3 (LSCr), much higher photovoltages can be realized.4 Such high temperature solid oxide photovoltaic (PV) cells are promising due to their possible combination with solid oxide electrolyzer cells (SOEC). By using a common electrode of a PV cell and an underlying SOEC it is possible to directly transfer light to chemical energy. However, optimization of voltage and power of such high temperature PV cells is still required. In this study, different materials (e.g. (La, Sr)(Cr,Mn)O3 (LSCrM), (La,Sr)CoO3 (LSC), (La,Sr)FeO3 (LSF) and NdNiO3 (NNO),…) were tested for their applicability in oxide solar cells and mechanistic insight in processes under UV is gained. 1. Merkle, R., De Souza, R.A., Maier, Angewandte Chemie - International Edition 2001, 40(11), 2126-2129. 2. Viernstein, A., Kubicek, M., Morgenbesser, M., Walch, G., Brunauer, G.C., Fleig, J., Advanced Functional Materials 2019, 29(23). 3. Walch, G., Rotter, B., Brunauer, G.C., Esmaeili, E., Opitz, A.K., Kubicek, M., Summhammer, J., Ponweiser, K., Fleig, J., Journal of Materials Chemistry A 2017, 5(4), 1637-1649. 4. Brunauer, G.C., Rotter, B., Walch, G., Esmaeili, E., Opitz, A.K., Ponweiser, K., Summhammer, J., Fleig, J., Advanced Functional Materials 2016, 26(1), 120-128. Poster Design by Eva Pycha and Stefan Smetaczek Sample preparation: On a single crystaline STO substrate, a thin film, e.g. LSCr or Au is deposited. Pt stripes are applied as a current collector. A porous Pt paste is brushed on the bottom side as a counter electrode. The top layer as well as the substrate are varied in this study. Measurements: The characterization is performed in air at 350 °C. The voltage/current is measured for 15 min withouth UV light, then for 15 min under UV light and then for 15 min after switching the UV light off. Multimeter / Impedance analyzer SrTiO3 single crystal La0.9Sr0.1CrO3 thin film UV lamp Porous Pt paste Pt stripes 15 min 30 min time voltage UV off UV on UV off Figure 1: Sketch of the sample (a) and a typical measurement (b) a) b) Optimization of the high temperature solar cell: The LSCrM/STO system is a very robust high temperature solar cell with photovoltages higher than 1 V at 350 °C. Other top layers also work with high photovoltages, such as Au. The variation of the substrate shows that STO as a substrate generally leads to high photovoltages in this study. Mechanistic insight in processes under UV light: Under UV light illumination, the resistance of the space charge region is switched off. Additionally, stoichiometry polarization leads to an increase in current under UV light (self-enhanced HT solar cell). A change in oxygen stoichiometry occurs forming an oxygen depleted region under the top layer (negative battery voltage). Top Layer Variation: LSCrM/STO Top Layer Variation: Other Materials Substrate Variation Current and Voltage Measurement Long-term Measurement: Current Figure 2: Variation of Sr and Mn content in LSCrM as a top layer Figure 4: Variation of the substrate Figure 3: Variation of the top l