Plasmonic solar cell

This article was registered in the quality assurance of the physics editorial team . If you are familiar with the topic, you are welcome to participate in the review and possible improvement of the article. The exchange of views about this is currently not taking place on the article discussion page , but on the quality assurance side of physics.

A plasmonic solar cell is a thin-film solar cell that uses plasmon to convert light into electricity. It is typically 2 μm thick, but can theoretically be up to 100 nm thick. One advantage is that materials that are cheaper than silicon can be used; glass, plastic or steel are used. One of the challenges for thin film solar cells is that they do not absorb as much light as thicker solar cells made from materials with similar absorption coefficients. This is why methods are used to capture light that are also important for other thin-film solar cells. In plasmonic cells, the absorption of light is improved by scattering on metal nanoparticles that are vaporized onto the surface and excited with their surface plasmon resonance. Incoming light at the plasmon resonance frequency induces electron oscillations of the nanoparticles on the surface. The oscillation electrons can then be captured by a conductive layer that generates an electrical current. The voltage generated depends on the band gap of the conductive layer and the potential of the electrolyte that is in contact with the nanoparticles. Significant research is still required for the technology to reach its full potential and commercialization of plasmonic enhanced solar cells.

history

Components

There are currently three generations of solar cells.

The currently commercially available solar cells made of crystalline wafers of silicon are made, it belong to the first generation . The silicon wafers have small pyramids made of SnO ₂ or ZnO on their surface in the order of magnitude of the wavelength of the light used, which absorb the incident light. This surface roughness increases the resulting photocurrent, but on the other hand results in a poorer quality of the material.

The second generation solar cells are thin layers . The main focus of this technological step is on reducing the material used and increasing the efficiency . The layers are thinner than the surface roughness of the first-generation solar cells.

The third generation solar cells are the current research area. The focus is on reducing manufacturing costs.

construction

The structure of plasmonic solar cells depends on the method used to capture the light and scatter it over the surface and through the material.

Solar cells made from nanoparticles

Plasmonic solar cell with metallic nanoparticles.

In a frequently used structure, metallic nanoparticles are applied to the surface of a thin-film solar cell . When light with the resonance frequency of the surface plasmons hits the nanoparticles, the light is scattered in different directions. This causes the light to move along the solar cell between the thin layer and the nanoparticles, causing the solar cell to absorb even more light. The high intensity of the near field, which is created by the surface plasmons of the metallic nanoparticles, supports the optical absorption of the semiconductor layer. In particular, it is asymmetrical plasmon modes that lead to optical absorption for a broad spectrum, and through which the electrical properties of the solar cell are enhanced. The simultaneous occurrence of effects of the plasmons with light on the one hand and of plasmon-electrical effects on the other hand promises interesting properties of the plasmons of the nanoparticles.

As reported by Peng Yu et al. explained, the application of pure metallic nanoparticles has some disadvantages: Contact with air or moisture changes the scattering behavior. The metal coating can also diffuse into the active layer of the solar cell, which has detrimental effects. For this reason, so-called core-shell nanostructures are being investigated. B. consists of a metallic sheath of a dielectric core. Such structures have vanishing backscattering and increased forward scattering on the silicon. Core-shell nanoparticles can have electrical and magnetic resonances at the same time and therefore have new properties compared to purely metallic nanoparticles.

Solar cells made from metal films

Another possibility to use surface plasmons when converting solar energy is to apply a metal layer on the underside of the thin silicon layer cell. The light penetrates the silicon and generates plasmons at the silicon-metal junction. The electric field hardly penetrates the metal, whereas an electric field is created in silicon . If this field is strong enough, released electrons can generate the photocurrent. Grooves on the order of nanometers serve as waveguides for the incident light

Basics

General

Comparison of a thin-film solar cell (left) with a conventional solar cell (right).

When a photon is absorbed in silicon, an electron-hole pair is created. The electrons and the holes have opposite charges and therefore try to recombine. However, if the electrons are intercepted before they can recombine, they can be used for an external circuit. The choice of the thickness of the solar cell weighs between the lowest possible recombination rate (which speaks for thinner layers) and the greatest possible absorption of photons (the latter speaks for thicker layers).

Individual evidence

1. ↑ J. Gwamuri, D.Ö. Güney, JM Pearce: Advances in Plasmonic Light Trapping in Thin-Film Solar Photovoltaic Devices . In: Atul Tiwari, Rabah Boukherroub, Heshwar Sharon (Eds.): Solar Cell Nanotechnology . John Wiley & Sons, Inc., 2013, ISBN 978-1-118-84572-1 , pp. 241-269 , doi : 10.1002 / 9781118845721.ch10 .
2. ^ ^{A b} Harry A. Atwater, Albert Polman: Plasmonics for improved photovoltaic devices . In: Nature Materials . tape 9 , no. 3 , February 19, 2010, p. 205–213 , PMID 20168344 , bibcode : 2010NatMa ... 9..205A ( nature.com ).
3. ↑ Joachim Müller, Bernd Rech, Jiri Springer, Milan Vanecek: TCO and light trapping in silicon thin film solar cells . In: Solar Energy . tape 77 , no. 6 , December 1, 2004, p. 917-930 , bibcode : 2004SoEn ... 77..917M ( sciencedirect.com ).
4. ^ KR Catchpole, A. Polman: Plasmonic solar cells . In: Optics Express . tape 16 , no. 26 , 2008, p. 21793-21800 ( opticsinfobase.org ).
5. ↑ Gavin Conibeer: Third generation photovoltaics . In: Proc. SPIE . tape 7411 , 74110D, August 20, 2009, doi : 10.1117 / 12.828028 .
6. ↑ Energy.gov: Solar Cell Materials ( Memento from January 27, 2010 in the Internet Archive )
7. ^ ^{A b} K. Tanabe: A Review of Ultrahigh Efficiency III-V Semiconductor Compound Solar Cells . Multijunction Tandem, Lower Dimensional, Photonic Up / Down Conversion and Plasmonic Nanometallic Structures. In: Energies . tape 2 , no. 3 , 2009, p. 504-530 .
8. ↑ Xingang Ren et al .: High Efficiency Organic Solar Cells Achieved by the Simultaneous Plasmon-Optical and Plasmon-Electrical Effects from Plasmonic Asymmetric Modes of Gold Nanostars . In: Small . tape 12 , no. 37 , 2016, p. 5200-5207 , doi : 10.1002 / smll.201601949 .
9. ↑ ^{a b} Peng Yu, Yisen Yao, Jiang Wu, Xiaobin Niu, Andrey L. Rogach, Zhiming Wang: Effects of Plasmonic Metal Core - Dielectric Shell Nanoparticles on the Broadband Light Absorption Enhancement in Thin Film Solar Cells . In: Scientific Reports . tape 7 , no. August 1 , 2017 ( nature.com ).
10. ↑ YA Akimov, WS Koh: Design of Plasmonic Nanoparticles for Efficient Subwavelength Light Trapping in Thin-Film Solar Cells . In: Plasmonics . tape 6 , 2010, p. 155-161 , doi : 10.1007 / s11468-010-9181-4 .
11. ↑ RB Jiang, BX Li, CH Fang, JF Wang: Metal / Semiconductor Hybrid Nanostructures for Plasmon-Enhanced Applications . In: Advanced materials . tape 26 , 2014, p. 5274-5309 , doi : 10.1002 / adma.201400203 .
12. ↑ Vivian E. Ferry, Luke A. Sweatlock, Domenico Pacifici, Harry A. Atwater: Plasmonic Nanostructure Design for Efficient Light Coupling into Solar Cells . In: Nano Letters . tape 8 , no. 12 , 2008, p. 4391-4397 , PMID 19367883 , bibcode : 2008NanoL ... 8.4391F .