Surfaceplasmons in solar power Enhancing Efficiency of Solar Cells and Solar Thermal Collectors with surface Plasmon Resonances in Metal Nanoparticles Antti Pennanen, Jouko Korppi-Tommola & Jussi Toppari OSKE Beneq Lamit.fi NSC Nanoscience Center UNIVERSITY OF JYVÄSKYLÄ

2 Introduction Properties of Silicon Abundant Cheap Stable Non-toxic Well-established industry  Most used photovoltaic material [Pillai et al. J.Appl.Phys. 101, , 2007.]

3 Introduction Fig. 1: AM1.5 standard solar irradiance spectrum. [Data from

4 Introduction Fig. 2: Optical absorption of silicon. [Shah, et al. Prog. Photovolt: Res. Appl. 12, 2004.]

5 Introduction c-Si –Expensive and difficult to fabricate a-Si & μc-Si –Cheap –High bulk recombination  cell thickness must be kept small Low optical absorption above 750 nm [Nelson: The Physics of Solar Cells, 2007.]

6 Introduction Possible solution: –Localized surface plasmons on metal nanoparticles

7 Localized Surface Plasmons Properties of sub-wavelength metal particles –Strong scattering and absorption of EM radiation at certain wavelengths –Correspond to resonant oscillations of e - gas  Localized surface plasmons [Optical data from Johnson and Christy: Phys.Rev. B 6, no.12, 1972.]

8 Localized Surface Plasmons Two ways to enhancement –Scattering –Absorption

9 Localized Surface Plasmons Scattering

10 Localized Surface Plasmons Excitation of Surface Plasmon

11 Localized Surface Plasmons Reradiation (scattering)

12 Localized Surface Plasmons Increased optical path  Enhanced optical absorption

13 Localized Surface Plasmons Absorption

14 Localized Surface Plasmons Excitation of Surface Plasmon

15 Localized Surface Plasmons Enhanced electric field in the Si  Direct generation of electron-hole pair

16 Results: 8.1% increase in total short circuit current output 8.3% increase in total power output [Derkacs et al. Appl.Phys.Lett 89, , 2006.]

17 Results: 3 to 7 fold max enhancement in photocurrent Up to 19% increase in total short circuit current output [Pillai et al. J.Appl.Phys.101, , 2007.] [Image of PERL cell: Zhao et al. Prog. Photovolt: Res. Appl. 7, 1999.]

18 Results: 13 to 17 fold max enhancement in photocurrent 16 to 33% increase in total short circuit current output [Pillai et al. J.Appl.Phys.101, , 2007.] [Image of SOI test device: Pillai et al. Appl.Phys.Lett. 88, , 2006.]

19 Results: 8.3% increase in total power output of a- Si:H p-i-n test cell [Derkacs et al. Appl.Phys.Lett. 89, , 2006.] 16% increase in total photocurrent output of a c-Si PERL cell [Pillai et al. J.Appl.Phys.101, , 2007.] 36% increase in total photocurrent output of a SOI test cell [Pillai et al. J.Appl.Phys.101, , 2007.]

20 Waveguide Solar Concentrator High-Efficiency Organic Solar Concentrators for Photovoltaics by Organic dye Molecules –Based on scattering to waveguide modes of the glass substrate –Solar cells around the glass –The dye-based organic solar concentrator functions without the use of tracking or cooling systems  greatly reduced the overall cost compared to other concentrator technologies. –Single- and tandem-waveguide organic solar concentrators with quantum efficiencies exceeding 50% [Michael J. Currie et al. Science 321, 226, 2008.]

21 1.Dye molecules coated on glass absorb sunlight, and re-emit it at a different wavelengths. 2.The light is trapped and transported within the glass until it is captured by solar cells at the edge.

22 Waveguide and LSP Metallic nanoparticles more robust than organic molecules Absorption tunable via resonance frequency Efficient scattering into waveguide modes –Proven by SOI solar cells before Suitable also for solar thermal?  Integrable Solar Thermal or Photovoltaic unit On-going Project: JYU/NSC, lamit.fi, Oske, Beneq

23 Solar Power Market Approximately 10 GWh of solar thermal (ST) capacity was in operation in Europe in 2005 Estimated: Global ST capacity will reach 100 milj. m 2 level by 2010 corresponding to 50 TWh per year Annual growth rate of ST business exceeds 20% Photovoltaics (PV) business and R&D field that is growing extremely rapidly, up to 30% a year The total installed global PV power approaches 8000 MWp this year.

24 Thank You