High efficiency solar cells by nanophotonic design

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1 High efficiency solar cells by nanophotonic design Piero Spinelli Claire van Lare Jorik van de Groep Bonna Newman Mark Knight Paula Bronsveld Frank Lenzmann Ruud Schropp Wim Sinke Albert Polman Center for Nanophotonics FOM-Institute AMOLF Amsterdam, The Netherlands Marc Verschuuren Dhritiman Gupta Martijn Wienk Bart Macco Erwin Kessels Rene Janssen Lourens van Dijk Guanchao Yin Martina Schmid Vivian Ferry Dennis Calahan Matt Sheldon Harry Atwater

2 Outline Light coupling and trapping Nanopatterned ARC on glass Transparent metal nanowire networks Plasmoelectric effect in metal nanostructures

3 light management J sc and V oc relative to SQ limit (at given bandgap) carrier management AMOLF

4 The scattering solar cell Light coupling and trapping by resonant light scatterers 4% n=1.0 n=3.5 96% H.A. Atwater and A. Polman Nature Mater. 9, 205 (2010), Nature Mater. 11, 174 (2012)

5 Silicon Mie scatterer on a Si substrate Si sphere Si cylinder Si Mie resonance Si Si Silicon nano-cylinders act as cavities for light and direct light into the substrate Si Piero Spinelli Nature Comm. 3, 692 (2012)

6 Black silicon using leaky Mie resonances Average reflectivity: 1.3% Si Si 3 N 4 Si Piero Spinelli Nature Comm. 3, 692 (2012)

7 Substrate conformal imprint lithography PDMS Stamp Thin glass PDMS stamp (6 ) on 200 µm AF-45 glass 1 m Full-wafer soft nano-imprint Flexible rubber on thin glass Conform to substrate bow and roughness No stamp damage due to particles Marc Verschuuren PhD thesis, Utrecht University (2010)

8 Light trapping in 5 m crystalline Si slab 100 FDTD simulation Mie (random) Si 3 N 4 Absorption (%) flat coating Mie (periodic) Si Back reflector t = 5µm Wavelength (nm) Piero Spinelli IEEE J. Photovolt. 4, 554 (2014)

9 Optimizing spatial frequency of scattering pattern Asahi U-type Claire van Lare ACS Photon. 2, 822 (2015)

10 Effect of EVA encapsulation Si EVA Si Piero Spinelli IEEE J. Photovolt. 5, 559 (2015)

11 TiO 2 nanoscatterers on Si Al 2 O 3 surface passivation TiO 2 Mie coating Si wafer ( = 3 ms) 5 nm Al 2 O 3 Bare Si wafer 5 nm Al 2 O % TiO 2 Mie coating 2.6% 1.6% Piero Spinelli, Bart Macco Appl. Phys. Lett. 102, (2013)

12 Nanopatterned Si solar cell designs Piero Spinelli, Bonna Newman

13 Ultra-thin a-si:h solar cell: 90 nm i layer 400 nm pitch Experiment patterned flat enhanced red and blue response by resonant dielectric Simulation scatterers 400 nm pitch 400 nm pitch flat flat 500 nm pitch 500 nm ITO pitch a-si:h ZnO:Al 500 nm Ag sol-gel Vivian Ferry, Claire van Lare Nano Lett. 11, 4239 (2011), Optics Express 21, (2013)

14 Nanopatterned CIGS solar cell designs TiO 2 AZO (240 nm) ITO (130 nm) CdS (100 nm) CIGS (460 nm) Mo (800 nm) nano nano + enhanced V oc flat flat reduced backrecombination Claire van Lare, Guanchao Yin ACS Nano 9, 9603 (2015)

15 Nanopatterned GaAs, thin crystalline Si simulations Piero Spinelli, Dennis Callahan, Lourens van Dijk

16 The solar cell as an optical integrated circuit =670 nm ITO a-si:h ZnO:Al Ag sol-gel 500 nm Vivian Ferry, Claire van Lare Nano Lett. 11, 4239 (2011), Optics Express 21, (2013)

17 Soft-imprinted nanopatterned AR interference coating Silica sol-gel Rubber stamp Nanoglass Flexible Silica nanopattern with effective index n= nm d = 240 nm h = 120 nm p = 325 nm Jorik van de Groep, Piero Spinelli Nano Lett. 15, 4223 (2015)

18 Measured total reflection Silica nanopattern on glass substrate 7.3 % 4.3 % 1.1 % Jorik van de Groep, Piero Spinelli Nano Lett. 15, 4223 (2015)

19 Nano-imprinted encapsulated Si solar cells 3.8% increase in photocurrent Jorik van de Groep, Piero Spinelli Nano Lett. 15, 4223 (2015)

20 Nano-imprinted smart phones flat patterned Jorik van de Groep, Piero Spinelli Nano Lett. 15, 4223 (2015)

21 Hydrophobicity Jorik van de Groep, Piero Spinelli Nano Lett. 15, 4223 (2015)

22 Transparent conductive silver nanowire network 2 m Ag nanowire network fabricated with electron beam lithography width: nm height: 60 nm Jorik van de Groep, Piero Spinelli Nano Lett. 12, 3138 (2012)

23 Transparent conductive silver nanowire network Optical transmission 45 nm 110 nm MIM plasmons Localized plasmons Surface plasmons I-V Ag nanowires can replace ITO Jorik van de Groep, Piero Spinelli Nano Lett. 12, 3138 (2012)

24 Ag nanowire network transparent conductors pitch 100 nm Ag nanowires on glass Jorik van de Groep, Dhritiman Gupta Sci. Rep. 5, (2015)

25 Metal nanowire printed Si HIT cells ITO: reduces J sc Ohmic losses Shading by Ag fingers Optical absorption Light reflection ITO dielectric function Drude absorption sunlight Ohmic losses shading ITO p+ a-si:h i a-si:h Ag fingers optical attenuation c-si wafer n type, FZ or CZ, <111> 50 µm 80 nm n interband absorption Wavelength (nm) k Synowicki, Thin Solid Films 313, 394 (1998) a-si:h i n+ a-si:h ITO Ag Mark Knight Jorik van de Groep

26 Metal nanowire printed Si HIT solar cells SCIL in silica sol-gel + Ag evaporation + lift-off Varying array pitch Width ~80 nm 1000 nm 800 nm 600 nm 400 nm Varying wire width Pitch 500 nm 63 nm 82 nm 101 nm 113 nm Mark Knight Jorik van de Groep

27 SCIL on FZ and CZ Si wafers Float-zone Si(100) mechanically polished Czochralski-grown Si(111) chemically polished 5 mm Flexible PDMS stamp conforms to rough substrate No stamp damage due to dust, roughness Mark Knight Jorik van de Groep

28 Nanoscale conformality of SCIL soft imprint Polished FZ Si Rough CZ Si height (nm) NW height: 50 nm position ( m) height (nm) NW height: 50 nm position ( m) Mark Knight Jorik van de Groep

29 Ag nanowire patterned Si heterojunction solar cells 80 nm ITO 20 nm ITO + Ag NW + SiNx Mark Knight, Jorik van de Groep, Paula Bronsveld

30 Ag nanowire patterned Si heterojunction solar cells NW pitch : 1 µm 2 µm 4 µm ITO only 1 cm 1 µm 80 nm ITO width: 80 nm height: 120 nm Mark Knight, Jorik van de Groep, Paula Bronsveld

31 Efficiency (%) FF J sc (ma cm -2 ) V oc (mw) Ag nanowire patterned Si heterojunction solar cells 1 µm 2 µm 4 µm no NW Mark Knight, Jorik van de Groep, Paula Bronsveld

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33 Soft imprinted nanowire networks 100 nm Jorik van de Groep, Dhritiman Gupta Sci. Rep. 5, (2015)

34 Absorption cross section (10-19 cm 2 ) Plasmon resonance depends on charge density 20 nm Ag sphere in vacuum R p ne m e * 2 0 Wavelength (nm) Jorik van de Groep, Matt Sheldon Science 346, 828 (2014)

35 Voltage (V) (nm) T(K) Plasmo-electric effect in metal nanostructures: thermodynamics Minimize free energy F(N,T) F( N, T) F F T N N T N T S N T N 0 0 o T/ N n/n 0 ( N, T) S( N, T) T N (nm) Jorik van de Groep, Matt Sheldon Science 346, 828 (2014)

36 Plasmo-electric potential: experiments Ag colloids on ITO Kelvin probe microscopy 60 nm Au Jorik van de Groep, Matt Sheldon Science 346, 828 (2014)

37 Plasmo-electric effect in metal nanostructures Jorik van de Groep, Matt Sheldon Science 346, 828 (2014)

38 Plasmo-electric effect on resonant Au hole arrays 100 mw/cm 2 Plasmo-electric potential spectral dependence shifts with array resonance Jorik van de Groep, Matt Sheldon Science 346, 828 (2014)

39 Plasmo-electric effect in metal nanostructures Jorik van de Groep, Matt Sheldon Science 346, 828 (2014)

40 Conclusions Light coupling and trapping Nanopatterned ARC on glass Transparent metal nanowire networks Plasmoelectric effect in metal nanostructures For details: see