How fast could the use of solar energy spread across the world if we could harvest it from ordinary windows, print solar cells onto paper and fabric, or eliminate the most costly materials used to create photovoltaic panels? Recent cutting-edge innovations in the solar power industry have made all of these things possible. The solar panels of the future are ultra-thin, flexible and transparent; they focus and absorb more energy than ever, even in shady conditions. In fact, as these 10 clean tech breakthroughs are developed into viable commercial applications, they could eliminate many of the obstacles preventing solar power from overtaking fossil fuels.

(photo credit: courtesy of twin creeks technologies)

1. Thinly-Sliced Solar Cells

The new, extra-slim solar cells produced by Twin Creek Technologies could transform the entire solar power industry, cutting total production costs from 85 cents per day to about 50 cents. Twin Creek’s ‘Hyperion’ machine allows solar manufacturers to make flexible silicon cells. Previously, it was difficult to get silicon wafers thinner than 200-microns because they get brittle, but the Hyperion system can create slices as thin as 20 microns. These thinner cells are just as efficient as thicker ones and could be used for building-integrated applications.

(photo credit: wikimedia commons)

2. Blackest Solar Cell Ever Designed

The more sunlight photovoltaic cells are able to absorb, the more efficient they are. A new black silicon solar cell developed by Natcore Technology scientists is the ‘blackest’ solar cell ever designed, absorbing 99.7 percent of the light cast upon it. Black solar cells are more efficient at capturing angled sunlight, and outperform current anti-reflective solar cells on cloudy days. The process of creating them is a simple liquid bath that uses no hazardous chemicals.

(photo credit: Geoffrey Supran/MIT)

3. Transparent Photovoltaic Cells for Solar Windows

Totally transparent solar cells developed by researchers at MIT could enable windows or even entire building facades that generate more than enough electricity to power the structure. Richard Lunt and the MIT team have created a photovoltaic cell based on organic molecules, which can be coated onto a pane of standard window glass. The molecules harness the energy of infrared light, while allowing visible light to pass through the glass. Up to half the cost of solar panels is for the glass and structural parts, so combining this technology with windows could potentially save a lot of money. While the prototype cells only reach an efficiency level of 1.7 percent, the researchers say they expect that figure to be comparable to existing commercial solar panels.

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4. Prism-Shaped Solar Cells that Focus Sunlight

Photovoltaic cells built into transparent panels with honeycomb-shaped prisms could maximize the amount of solar energy that is captured and converted into electricity. BeeHive PV, by Israeli startup SolarOr, is designed to integrate into building facades. Each sheet of prisms is made of acrylic, which also has insulating properties. The slanting of the prisms within each panel is even customizable, so it can be tailored to specific locations.

(photo credit: wikimedia commons)

5. Efficiency-Increasing Micro-inverters

Solar installations typically have one large central inverter that converts direct current from a group of solar panels into AC power, but micro-inverters could be much more efficient. Solar micro-inverters are installed on each individual solar panel. Isolating each solar panel in this way makes it much easier to monitor the output of each panel and pinpoint equipment failures.

(photo credit: idaho national laboratory)

6. Light-Absorbing Nano-Antennas

When metallic antennas are adapted to absorb light waves at optical frequencies and embedded in large sheets of plastic, they can convert those waves to usable energy at a much higher rate than current technology – at a lower cost. Researchers at Tel Aviv University’s Department of Physical Electronics have developed a solar panel composed of these nano-antennas that convert 95 percent of the wattage received from sunlight into electromagnetic energy. When they’re manufactured in different lengths, these nano-antennas can also collect wavelengths across a much broader spectrum of light. The researchers are currently focusing on the converting that energy into electric current.

(photo credit: Patrick Gillooly/MIT)

7. Printable Solar Cells

What if you could quickly and cheaply print solar cells onto virtually any untreated surface, like paper or fabric? Researchers at MIT have developed technology that may soon make that impossible-sounding feat a reality. A new solar cell printing process uses vapors and temperatures less than 120 degrees Celsius, so that the cells can be printed onto inexpensive, easily available materials. The paper can then be folded or coated with standard lamination materials. The researchers hope to refine the process in order to increase the efficiency, but according to MIT Professor of Electrical Engineering Vladimir Bulović, the current rate of about one percent is “good enough to power a small electric gizmo.”

(photo credit: Allegra Boverman/MIT)
8. Three-Dimensional Designs

Is flat against a rooftop or other surface really the best way for solar panels to capture the maximum amount of sunlight? A team of MIT researchers believes that re-thinking the arrangement of solar cells could dramatically increase their energy output. Building three-dimensional configurations that extend the solar cells upward, the team has measured power outputs ranging from double to more than 20 times those  of fixed flat panels with the same base area. The complexity of the panels themselves causes an increase in cost, but it’s more than made up for by the increased energy output for a given footprint.  The vertical surfaces of these 3D solar structures are able to capture much more sunlight during morning and evening hours, and in the winter. A company called Solar3D is working on similar technology, claiming 200% of the power output of conventional solar cells.

(photo credit: green sun energy)
9. Colored Solar Panels that Don’t Need Direct Sunlight

Even a little shade can make it hard to gather enough sunlight to convert into electricity, making many locations unsuitable for solar panel installations. But a new type of solar cell by Green Sun Energy in Tel Aviv can generate power even from diffused light, thanks to fluorescent dyes and nanoparticle metals. Using 80% less silicon than traditional solar cells, these colored panels have a 12% efficiency rate and can be produced for less than half the cost of conventional panels. When direct or indirect sunlight hits these panels, the pigment helps spread it out. The nanoparticles of metal direct the sunlight to the edges of the panels, where the silicon is located. GreenSun hopes to achieve an efficiency rate of 20% and reduce the cost even more, to $0.94 per watt.

(photo credit: wikimedia commons)

10. Silicon Nano-rods that Use 99% Less Material

‘Whiskers’ of silicon could do the job of an entire silicon wafer, vastly cutting down on the use of this expensive material per solar cell. Researchers at the California Institute of Technology in Pasadena, California are creating ‘micro-carpets’ of silicon nano-rods that can produce electricity for a fraction of the cost of current technology. The team used an established technique of assembling nanowires in a surface, growing a carpet of micrometer-scale silicon rods embedded in a transparent polymer. While the team has not yet established an efficiency rating, researcher Harry Atwater says the resulting flexible material outperforms conventional silicon wafers at absorbing infrared frequencies.