The emerging field of plasmonics has yielded methods for guiding and localizing light at the nanoscale, well below the scale of the wavelength of light in free space. Now plasmonics researchers are turning their attention to photovoltaics, where design approaches based on plasmonics can be used to improve absorption in photovoltaic devices, permitting a considerable reduction in the physical thickness of solar photovoltaic absorber layers, and yielding new options for solar-cell design. In this review, we survey recent advances at the intersection of plasmonics and photovoltaics and offer an outlook on the future of solar cells based on these principles.

Plasmonics for improved photovoltaic devices

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since July 2014 are reviewed. URI: http://onlinelibrary.wiley.com/doi/10.1002/pip.2573/pdf [1] Authors: GREEN Martin A. EMERY Keith HISHIKAWA Y. WARTA W. DUNLOP Ewan Publication Year: 2015 Type: Articles in Journals

Solar Cell Efficiency Tables (Version 45)

S. Pillai would like to acknowledge the UNSW Faculty
of Engineering Research Scholarship. K.R. Catchpole
acknowledges the support of an Australian Research Council fellowship.

/pdf/surface-plasmon-enhanced-silicon-solar-cells-3duyubxz7i.pdf

Surface plasmon enhanced silicon solar cells

Recent developments in photovoltaic materials have led to continual improvements in their efficiency. We review the electrical characteristics of 16 widely studied geometries of photovoltaic materials with efficiencies of 10 to 29%. Comparison of these characteristics to the fundamental limits based on the Shockley-Queisser detailed-balance model provides a basis for identifying the key limiting factors, related to efficient light management and charge carrier collection, for these materials. Prospects for practical application and large-area fabrication are discussed for each material.

/pdf/photovoltaic-materials-present-efficiencies-and-future-3yblyv6m8p.pdf

Photovoltaic materials: Present efficiencies and future challenges

The silicon chip has been the mainstay of the electronics industry for the last 40 years and has revolutionized the way the world operates. Today, a silicon chip the size of a fingernail contains nearly 1 billion transistors and has the computing power that only a decade ago would take up an entire room of servers. As the relentless pursuit of Moore's law continues, and Internet-based communication continues to grow, the bandwidth demands needed to feed these devices will continue to increase and push the limits of copper-based signaling technologies. These signaling limitations will necessitate optical-based solutions. However, any optical solution must be based on low-cost technologies if it is to be applied to the mass market. Silicon photonics, mainly based on SOI technology, has recently attracted a great deal of attention. Recent advances and breakthroughs in silicon photonic device performance have shown that silicon can be considered a material onto which one can build optical devices. While significant efforts are needed to improve device performance and commercialize these technologies, progress is moving at a rapid rate. More research in the area of integration, both photonic and electronic, is needed. The future is looking bright. Silicon photonics could provide low-cost opto-electronic solutions for applications ranging from telecommunications down to chip-to-chip interconnects, as well as emerging areas such as optical sensing technology and biomedical applications. The ability to utilize existing CMOS infrastructure and manufacture these silicon photonic devices in the same facilities that today produce electronics could enable low-cost optical devices, and in the future, revolutionize optical communications

http://ieeexplore.ieee.org/iel5/6668/34347/01638290.pdf

Silicon photonics

Multicrystalline silicon wafers, widely used in commercial photovoltaic cell production, traditionally give much poorer cell performance than monocrystalline wafers (the previously highest performance laboratory devices have solar energy conversion efficiencies of 186% and 240%, respectively) A substantially improved efficiency for a multicrystalline silicon solar cell of 198% is reported together with an incremental improvement in monocrystalline cell efficiency to 244% The improved multicrystalline cell performance results from enshrouding cell surfaces in thermally grown oxide to reduce their detrimental electronic activity and from isotropic etching to form an hexagonally symmetric “honeycomb” surface texture This texture reduces reflection loss as well as substantially increasing the cell’s effective optical thickness by causing light to be trapped within the cell by total internal reflection

19.8% efficient “honeycomb” textured multicrystalline and 24.4% monocrystalline silicon solar cells

A new silicon solar cell structure, the passivated emitter and rear cell, is described. The cell structure has yielded independently confirmed efficiencies of up to 22.8%, the highest ever reported for a silicon cell.

22.8% efficient silicon solar cell

This paper reports the recent improvements in the energy conversion efficiencies of solar cells on magnetically-confined Czochralski grown (MCZ) and float zone (FZ) silicon substrates at the University of New South Wales. A PERT (passivated emitter, rear totally-diffused) cell structure has been used to reduce the cell series resistance from higher resistivity substrates. The total rear boron diffusion in this PERT structure appears to improve the surface passivation quality of MCZ and some FZ substrates. Hence, higher open-circuit voltages were observed for some PERT cells. One of these cells on MCZ substrates demonstrated 24·5% energy conversion efficiency at Sandia National Laboratories under the standard global spectrum (100 mW/cm2) at 25°C. This is the highest efficiency ever reported for a MCZ silicon solar cell. The cells made on MCZ substrates also showed stable cell performance rather than the usually reported unstable performance for boron-doped CZ substrates. Also reported is a PERL (passivated emitter, rear locally-diffused) cell on a FZ substrate of 24·7% efficiency, which is the highest efficiency ever reported for any silicon solar cell. Copyright © 1999 John Wiley & Sons, Ltd.

24·5% Efficiency silicon PERT cells on MCZ substrates and 24·7% efficiency PERL cells on FZ substrates

Considerable effort is being expended on the development of efficient silicon light-emitting devices compatible with silicon-based integrated circuit technology. Although several approaches are being explored, all presently suffer from low emission efficiencies, with values in the 0.01-0.1% range regarded as high. Here we report a large increase in silicon light-emitting diode power conversion efficiency to values above 1% near room temperature-close to the values of representative direct bandgap emitters of a little more than a decade ago. Our devices are based on normally weak one- and two-phonon assisted sub-bandgap light-emission processes. Their design takes advantage of the reciprocity between light absorption and emission by maximizing absorption at relevant sub-bandgap wavelengths while reducing the scope for parasitic non-radiative recombination within the diode. Each feature individually is shown to improve the emission efficiency by a factor of ten, which accounts for the improvement by a factor of one hundred on the efficiency of baseline devices.

Efficient silicon light-emitting diodes

Antireflection coatings for silicon solar cells have been optimized both theoretically and experimentally for a range of possible situations, such as single-layer and double-layer coatings, and on planar and microgrooved surfaces. The effect of a thin passivating silicon dioxide layer under the coating was also considered. A critical passivating oxide thickness of about 300 AA was found to be important for the design of these coatings. A new half-quarter-wavelength double layer antireflection coating can be achieved with very low reflection if the passivating oxide has to be thicker than this critical thickness. >

Jianhua Zhao

Papers

19.8% efficient “honeycomb” textured multicrystalline and 24.4% monocrystalline silicon solar cells

22.8% efficient silicon solar cell

24·5% Efficiency silicon PERT cells on MCZ substrates and 24·7% efficiency PERL cells on FZ substrates

Efficient silicon light-emitting diodes

Optimized antireflection coatings for high-efficiency silicon solar cells