Passivation at the interface between liquidphase crystallized silicon and silicon oxynitride in thin film solar cells

Passivation at the interface between liquidphase crystallized silicon and silicon oxynitride in thin film solar cells Dr. Jan Amaru Palomino Töfflinger, Sección Física, Pontificia Universidad Católica del Perú Natalie Preissler, Dr. Onno Gabriel, Dr. Daniel Amkreutz, Dr. Bernd Stannowski, Dr. Rutger Schlatmann, Dr. Bernd Rech. Helmholtz-Zentrum Berlin für Materialien und Energie

Grupo de Materiales (Sección Física, PUCP) Total: 18 Líneas de investigación Semiconductores con tierras raras para celdas solares y dispositivos luminiscentes Roland Weingärtner Amaru Töfflinger Andrés Guerra 3 Científicos/ PhD Materiales de pasivación en celdas solares de silicio Caracterización de a-sic:h para la producción foto-electroquímica de hidrogeno Publicaciones 2016 en revistas indexadas N. Preissler, J. A. Töfflinger, et al., Progress in Photovoltaics, accepted (2016) 3 Doctorandos 10 Maestrandos J. A. Guerra, et al., J. Phys. D: Appl. Phys. 49, 375104. (2016) N. Preissler, J. A. Töfflinger, et al., Phys. Status Solidi A 213 (7), 1697 (2016) J. A. Guerra, et al., J. Phys. D: Appl. Phys. 49, 195102. (2016) 1 Tesista Lic. 1 Assistente Proyectos en ejecución J. A. Guerra (PUCP-HZB), Proyecto de movilidad DAAD-Concytec R. Weingärtner (PUCP-Ilmenau), Proyecto de movilidad DAAD-Concytec J. A. Töfflinger (PUCP), Innóvate Perú, Repatriación, 274-PNICP-BRI-2015 Producción Caracterización Aplicación Magnetron sputtering SiC:Tb 3+ Other: AlN:H, SiN:H, ITO... Optical properties Structural properties TEM SiC:H CL Intensities [a.u.] Rare earth luminescence 1 D 3 1 G 3 2 H 4 4 H 6 Tm3+ 5 D 7 4 F 5 4 F 9/2 6 H 13/2 5 D 0 7 F 1,2 Sm 3+ 4 G 5/2 6 H 7/2 4 G 5/2 6 H 9/2 2 F 5/2 2 F 7/2 Tb 3+ Dy 3+ Eu 3+ Yb 3+ 200 400 600 800 1000 Wavelength [nm] Thin-film solar cell LPC-Si liquid Si In cooperation with line-shaped laser or e-beam a-si (10 20 µm) Electrical properties IL ( 200 nm) glass (1 3 mm) 2

State of the art - commertial solar modules Fraunhofer ISE: Photovoltaics Report, updated: 6 June 2016 3

Standard Crystalline Silicon solar panel? Source: McGehee, Energy Seminar 2014 4

> 200 µm The Photovoltaic effect ARC + Front passivation (standard SiN x ) 1. + (n+) Standard mc-si (p) Solar cell efficiency η 16% 1. Absorption of light and generation of charge carriers 3. 2. - + mc-si (p) Al-BSF (p++) 2. Separation of charge carriers (p/n-junction: E-field) 3. Extract photo-voltage and -current -> electric power Solar cell efficiency η: η 5

< 150 µm > 200 µm Trend in the silicon wafer based solar cells Standard solar cell η 16% + (n + ) c-si (CZ, mc) (p) FS contact ARC Emitter Passivated Emitter and Rear Cell (PERC) η > 18% + (n + ) Absorber c - Si (CZ, mc ) (p) Al (p ++ ) Passivation stack Heterojunction solar cell (HIT) η > 20% + + ) ( n c-si (CZ, mc) (p) RS contact TCO a-si:h (n) a-si:h (i) Si-Absorber Key technology: high level passivation!!! + ( a-si:h (i) a-si:h (p) TCO 6

Trend in the silicon wafer based solar cells < 150 µm e.g. a-sin Passivated Emitter and Rear Cell (PERC) η > 18% + Q f + (n + ) D it - + c - Si (CZ, mc ) (p) c-si - + - + Surface passivation = Reduction of the recombination of photogenerated charge carriers at surfaces Main recombination parameters: Interface defect state density D it Fixed charge density Q f Chemical passivation Field-effect passivation 7

Trends in solar cell technology and research Efficiency 50% 40% 20% Dye organics Thin film c-si wafer III/V Conc. Cost per area https://educast.pucp.edu.pe/speaker/2864 8

~ 180 µm 1. Reduce c-si cost: LPC-Si thin film 2016: 90% market share for crystalline Si Silicon material: 30-40% of solar module cost Commercial solar cell Efficiency η = 15-16 % + (n+) mc-si (p) Al-BSF (p++) 9

Reduce c-si cost: LPC-Si thin film Thin-film, liquid-phase-crystallized (LPC)-Si solar cells, Efficiency η = 13.2% O. Gabriel et al., Prog. Photovolt: Res. Appl., doi: 10.1002/pip.2707 (2015) T. Frijnts, et. al., Solar Energy Materials & Solar Cells 143 457-466 (2015) S. Kühnapfel, et. al., Solar Energy Materials & Solar Cells 140 86-91 (2015) 10

Reduce c-si cost: LPC-Si thin film Thin-film, liquid-phase-crystallized (LPC)-Si solar cells, Efficiency η = 13.2% laser-crystallization O. Gabriel et al., Prog. Photovolt: Res. Appl., doi: 10.1002/pip.2707 (2015) T. Frijnts, et. al., Solar Energy Materials & Solar Cells 143 457-466 (2015) S. Kühnapfel, et. al., Solar Energy Materials & Solar Cells 140 86-91 (2015) 11

Reduce c-si cost: LPC-Si thin film Thin-film, liquid-phase-crystallized (LPC)-Si solar cells, Efficiency η = 13.2% laser-crystallization a-si LPC-Si V oc = 640 mv J sc = 28 ma/cm 2 FF = 74 % η = 13.2 % O. Gabriel et al., Prog. Photovolt: Res. Appl., doi: 10.1002/pip.2707 (2015) T. Frijnts, et. al., Solar Energy Materials & Solar Cells 143 457-466 (2015) S. Kühnapfel, et. al., Solar Energy Materials & Solar Cells 140 86-91 (2015) 12

LPC-Si thin film: Interface Passivation Thin-film, liquid-phase-crystallized (LPC)-Si solar cells, Efficiency η = 13.2% PUCP: Characterize electrical properties of LPC-Si/interlayer interface S I M Publications in colaboration HZB PUCP: N. Preissler, J. A. Töfflinger, et al. (2016) Phys. Status Solidi A 213 (7), 1697 N. Preissler, J. A. Töfflinger, et al. (2016) Progress in Photovoltaics, accepted for publication 13

LPC-Si thin film: Interface Passivation C-V samples Q IL,eff & D it solar cells V oc & J sc,eqe Thermal treatments Hatm30: H 2 atmosphere, 30 min, 400 C Hpla15: H 2 plasma, 15 min, 400 C Hpla30: H 2 plasma, 30 min, 400 C Q IL,eff > 10 12 cm -2 barely affected D it,mg [10 12 ev -1 cm -2 ] 3.0 2.5 2.0 1.5 1.0 0.5 0.0 n n-doped LPC-Si p-doped LPC-Si p V oc [mv] J sc,eqe [ma/cm 2 ] 650 600 550 500 18 16 14 0.0 0.5 1.0 1.5 2.0 2.5 D it,mg [ev -1 cm -2 ] n-doped LPC-Si p-doped LPC-Si Simulations: Interface is well passivated by field-effect, bulk passivation dominates N. Preissler, J. A. Töfflinger, et al. (2016) Progress in Photovoltaics, accepted for publication

LPC-Si thin film: Interface Passivation C-V samples Q IL,eff & D it solar cells V oc & J sc,eqe Thermal treatments Hatm30: H 2 atmosphere, 30 min, 400 C Hpla15: H 2 plasma, 15 min, 400 C Hpla30: H 2 plasma, 30 min, 400 C Q IL,eff > 10 12 cm -2 barely affected D it,mg [10 12 ev -1 cm -2 ] 3.0 2.5 2.0 1.5 1.0 0.5 0.0 n n-doped LPC-Si p p-doped LPC-Si V oc [mv] J sc,eqe [ma/cm 2 ] 650 600 550 500 18 16 14 0.0 0.5 1.0 1.5 2.0 2.5 D it,mg [ev -1 cm -2 ] Simulations: Interface is well passivated by field-effect, bulk passivation dominates N. Preissler, J. A. Töfflinger, et al. (2016) Progress in Photovoltaics, accepted for publication n-doped LPC-Si p-doped LPC-Si

Best research-cell efficiencies http://www.nrel.gov/pv/ 16

Best research-cell efficiencies Multijunction and GaAs cells $$$$ Space & concentrator applications Fraunhofer ISE / Soitec 46.0 % Crystalline Si cells $$ Commercial use Panasonic (HIT) 25.6 % SunPower 25.0 % Thin-Film cells $$ Commercial use ZSW (CIGS) 21.7 % Emerging PV $ Unstable, mostly low efficiency KRICT (Perovskite) 20.1 % http://www.nrel.gov/pv/ 17

More information about PV technologies DelftX: ET3034x Solar Energy https://www.edx.org/course/solar-energy-delftx-et3034x-0 http://pveducation.org/pvcdrom 18

Acknowledgements Materials Science group, Sección Física Roland Weingärtner, Andrés Guerra Norbert Nickel, Walter Füssel, Bernd Stannowski, Ivo Rudolph PNICP contract N o 274-PNICP-BRI-2015