2,219 research outputs found
Photovoltaic technologies
Photovoltaics is already a billion dollar industry. It is experiencing rapid growth as concerns over fuel supplies and carbon emissions mean that governments and individuals are increasingly prepared to ignore its current high costs. It will become truly mainstream when its costs are comparable to other energy sources. At the moment, it is around four times too expensive for competitive commercial production. Three generations of photovoltaics have been envisaged that will take solar power into the mainstream. Currently, photovoltaic production is 90% first-generation and is based on silicon wafers. These devices are reliable and durable, but half of the cost is the silicon wafer and efficiencies are limited to around 20%. A second generation of solar cells would use cheap semiconductor thin films deposited on low-cost substrates to produce devices of slightly lower efficiency. A number of thin-film device technologies account for around 5–6% of the current market. As second-generation technology reduces the cost of active material, the substrate will eventually be the cost limit and higher efficiency will be needed to maintain the cost-reduction trend. Third-generation devices will use new technologies to produce high-efficiency devices. Advances in nanotechnology, photonics, optical metamaterials, plasmonics and semiconducting polymer sciences offer the prospect of cost-competitive photovoltaics. It is reasonable to expect that cost reductions, a move to second-generation technologies and the implementation of new technologies and third-generation concepts can lead to fully cost- competitive solar energy in 10–15 years
Multilayer nanoparticle arrays for broad spectrum absorption enhancement in thin film solar cells
In this paper, we present a theoretical study on the absorption efficiency
enhancement of a thin film amorphous Silicon (a-Si) photovoltaic cell over a
broad spectrum of wavelengths using multiple nanoparticle arrays. The light
absorption efficiency is enhanced in the lower wavelengths by a nanoparticle
array on the surface and in the higher wavelengths by another nanoparticle
array embedded in the active region. The efficiency at intermediate wavelengths
is enhanced by the simultaneous resonance from both nanoparticle layers. We
optimize this design by tuning the radius of particles in both arrays, the
period of the array and the distance between the two arrays. The optimization
results in a total quantum efficiency of 62.35% for a 300nm thick a-Si
substrate.Comment: - Article Published in Optics Express on 7 Apr 2014. Link:
http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-103-A80
High temperature epsilon-near-zero and epsilon-near-pole metamaterial emitters for thermophotovoltaics
We propose a method for engineering thermally excited far field
electromagnetic radiation using epsilon-near-zero metamaterials and introduce a
new class of artificial media: epsilon-near-pole metamaterials. We also
introduce the concept of high temperature plasmonics as conventional
metamaterial building blocks have relatively poor thermal stability. Using our
approach, the angular nature, spectral position, and width of the thermal
emission and optical absorption can be finely tuned for a variety of
applications. In particular, we show that these metamaterial emitters near 1500
K can be used as part of thermophotovoltaic devices to surpass the full
concentration Shockley-Queisser limit of 41%. Our work paves the way for high
temperature thermal engineering applications of metamaterials.Comment: 15 pages, 8 figure
Enhanced Efficiency of Light-Trapping Nanoantenna Arrays for Thin Film Solar Cells
We suggest a novel concept of efficient light-trapping structures for
thin-film solar cells based on arrays of planar nanoantennas operating far from
plasmonic resonances. The operation principle of our structures relies on the
excitation of chessboard-like collective modes of the nanoantenna arrays with
the field localized between the neighboring metal elements. We demonstrated
theoretically substantial enhancement of solar-cell short-circuit current by
the designed light-trapping structure in the whole spectrum range of the
solar-cell operation compared to conventional structures employing
anti-reflecting coating. Our approach provides a general background for a
design of different types of efficient broadband light-trapping structures for
thin-film solar-cell technologically compatible with large-area thin-film
fabrication techniques
Plasmonic Metamaterials: Physical Background and Some Technological Applications
New technological frontiers appear every year, and few are as intriguing as the field of plasmonic metamaterials (PMMs). These uniquely designed materials use coherent electron oscillations to accomplish an astonishing array of tasks, and they present diverse opportunities in many scientific fields.
This paper consists of an explanation of the scientific background of PMMs and some technological applications of these fascinating materials. The physics section addresses the foundational concepts necessary to understand the operation of PMMs, while the technology section addresses various applications, like precise biological and chemical sensors, cloaking devices for several frequency ranges, nanoscale photovoltaics, experimental optical computing components, and superlenses that can surpass the diffraction limit of conventional optics
Light trapping in ultrathin plasmonic solar cells
We report on the design, fabrication, and measurement of ultrathin film a-Si:H solar cells with nanostructured plasmonic back contacts, which demonstrate enhanced short circuit current densities compared to cells having flat or randomly textured back contacts. The primary photocurrent enhancement occurs in the spectral range from 550 nm to 800 nm. We use angle-resolved photocurrent spectroscopy to confirm that the enhanced absorption is due to coupling to guided modes supported by the cell. Full-field electromagnetic simulation of the absorption in the active a-Si:H layer agrees well with the experimental results. Furthermore, the nanopatterns were fabricated via an inexpensive, scalable, and precise nanopatterning method. These results should guide design of optimized, non-random nanostructured back reflectors for thin film solar cells
- …