Vacuum and in-air thermal stability studies of SnO 2 -based TCO for - PowerPoint PPT Presentation

Vacuum and in-air thermal stability studies of SnO 2 -based TCO for concentrated solar power applications (CSP) Álvaro Méndez Fernández 1 , Frank Lungwitz 2 , Erik Schumann 2 , Daniel Janke 2 , Elena Guillén 3 , Ramón Escobar Galindo 4 , Sibylle Gemming 2 , Iván Fernández-Martínez 1 , Matthias Krause 2 1 NANO4ENERGY SLNE, Madrid, Spain. 2 Helmholtz-Zentrum Dresden – Rossendorf, Dresden, Germany. 3 Profactor GmbH, Steyr-Gleink, Austria. 4 IMEYMAT Universidad de Cádiz, Cádiz, Spain. Garmisch, September 21st, 2018. Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Contents  Introduction  Another approach for CSP  Results  Thermal stability  Conclusions Page 2 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Introduction  What is CSP?  Concentrating Solar Power: Redirect and concentrate the light onto an absorber in which light is converted into heat Tower Plant Parabolic Trough Linear Fresnel Parabolic Dishes Page 3 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Introduction  Solar Selectivity  Requirements 2,0 1,0 Solar intensity / [W/(m²nm)] Ideal Sele ctive Solar Radiation  High absorbance on UV-vis- Absorber (AM 1.5) 0,8 1,5 BB Intensity / a.u. NIR Reflectivity Black Body Radiation  High reflectance from IR range 0,6 (800 °C) 1,0 0,4 0,5 Kirchhoff’s law of 0,2 thermal radiation 0,0 0,0 0 500 1000 1500 2000 2500 3000 3500 Wavelength / nm Page 4 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Introduction  Absorber designs [PhD thesis Irene Heras, Multilayer solar selective coatings for high temperature solar applicaions: From concept to design] Page 5 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Another approach for CSP Solar Radiation  Properties of the TCO  Transparent in the VIS and NIR Selective Transmitter (TCO)  Reflective in the IR (>2000 nm) Black Body Absorber  Stable at high temperature Heat - transfer - fluid  Experimental setup  Co-sputtering from Sn and Sn:Ta targets  Heat is applied during deposition  Ar and O 2 as gases  Ta selected because its refractory properties Page 6 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Another approach for CSP  The cut-off wavelength Increasing selectivity 𝜇 cut−off Shorter λ cut-off  High N e and high μ opt Higher selectivity TAILORING OF PROPERTIES IS POSSIBLE Page 7 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Results  Optical characterization  High Transmittance in UV-vis  Good Reflectance in vis-IR Page 8 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Results  Influence of deposition parameters: Ta content Page 9 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Results  Influence of parameters: O 2 and Temperature 16 16 14 15 -1 12 -1 -1 s -1 s 14 570 ° C 2 V 2 V 10 13 Mobility µ / cm Mobility µ / cm 8 12 6 11 4 10 2 9 0 8 9 10 11 12 13 14 15 16 17 18 400 450 500 550 600 650 O 2 -Flow / sccm Deposition temperature / °C  Vacancies go up to a limit but afterwards they start getting filled Page 10 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Results  Influence of parameters: Thickness  Little variations in spectrum (not following a trend) Thickness is not a critical factor Page 11 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Results  Best achieved 𝑂 𝑓 = 4.3 ± 0.3 × 10 20 cm −3 𝜈 𝑓𝑚𝑓𝑑𝑢 = 14 ± 3 cm 2 V −1 s −1 𝜈 𝑝𝑞𝑢 = 35 ± 3 cm 2 V −1 s −1 Highly suitable for CSP applications Page 12 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Thermal Stability  The Cluster Tool  in-situ RBS and ERDA  in-situ Ellipsometry  in-situ Raman  Nanoindenter  Sputtering chamber  UP TO 1000ºC Page 13 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Thermal Stability  Rutherford Backscattering (vacuum) Sn & Ta 2 MeV He + ~ 20 nA α = 155º Temp. = 800ºC Si O Conservation of element  RBS spectrum doesn’t vary distribution Page 14 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Thermal Stability 𝐹  Ellipsometry (vacuum) Same optical properties  Tiny changes in Ψ and Δ and layer thickness Page 15 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Thermal Stability  Reflectance and Transmittance (in-air tests) Stable at Slight changes within measurement accuracy 800ºC!!!! Page 16 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Conclusions  A TCO based on Sn and Ta for high temperature solar thermal applications was developed and optimized  Perfect agreement of simulated and experimental data was found  Thermal stability tests in both vacuum and in-air atmospheres were carried out showing excellent results at high temperature Page 17 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu

 Acknowledgments A. Wennberg R. Wenisch S. Muñoz J. Zscharschuch A. Scholz J. Grenzer This work was financially supported by A. Schneider the EU H2020 RISE project “Framework D. Flath of Innovation for Engineering of New R. Heller Durable Solar Surfaces (FRIENDS 2 , GA- IBC Operator Team 645725)” and the Initiative and G. Abrasonis (now EPO) Networking Funds of the president of A. Erbe the Helmholtz Association via the J. Faßbender W2/W3 program (SG). M. Helm THANK YOU FOR YOUR ATTENTION Page 18 Member of the Helmholtz Association Álvaro Méndez I Nanocomposite Division I www.nano4energy.eu I www.hzdr.de I www.friends2project.eu