Fuller Spectrum Solar Energy Harvesting: Transparent Window Collectors Capture Ultraviolet End of Spectrum

Full spectrum sunlight ranges from the longer infrared wavelengths to the shorter wavelength ultraviolet. While nano-antennas can capture up to 70% of infrared radiation, a new nano-silicon technology from Octillion (OCTL) can capture between 50% and 60% of ultraviolet energy. When incorporated into windows, such "solar collectors" allow most visible light through, while capturing the energy from the shorter wavelength photons.

Octillion’s NanoPower Window(TM) technology uses silicon nanoparticles that have the potential to convert conventional home, office and industrial glass windows into those capable of converting solar energy into electricity. The silicon nanoparticles are created through a unique electrochemical and ultrasound process that produces identically sized (1 to 4 nanometers in diameter) highly luminescent nanoparticles of silicon that provide varying wavelengths of photoluminescence with high quantum down-conversion efficiency of short wavelengths (50% to 60%).

“Our silicon nanoparticles are the foundation of our NanoPower Windows,” states Mr. Nicholas S. Cucinelli, President and CEO of Octillion Corp. “In fact, independent tests have shown that the same silicon nanoparticles used in Octillion’s NanoPower Window(TM) are also able to enhance the power output of conventional solar cells by up to 70% in the ultraviolet light range and 10% in the visible.

... When thin films of silicon nanoparticles are deposited (sprayed) onto silicon substrates, ultraviolet light is absorbed and converted into electrical current. With appropriate connections, the films act as nanosilicon photovoltaic solar cells that convert solar radiation to electrical energy.

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H/T and Image Credit to Next Energy News

One can easily see how the Octillion technology would complement both conventional PV and nano-antenna solar energy. Clearly, the convergence of nano-technology and solar energy is creating a huge opportunity for renewable energy.

Update: Click on "Read More" below for information about another nano-solar approach to extend the spectrum of PV.

Combining doped thin film metal oxide nano-particles with nano quantum dot crystals, gives a potentially much more efficient PV system.

Two nanotech methods for engineering solar cell materials have shown particular promise. One uses thin films of metal oxide nanoparticles, such as titanium dioxide, doped with other elements, such as nitrogen. Another strategy employs quantum dots--nanosize crystals--that strongly absorb visible light. These tiny semiconductors inject electrons into a metal oxide film, or "sensitize" it, to increase solar energy conversion. Both doping and quantum dot sensitization extend the visible light absorption of the metal oxide materials.

Combining these two approaches appears to yield better solar cell materials than either one alone does, according to Jin Zhang, professor of chemistry at the University of California, Santa Cruz. Zhang led a team of researchers from California, Mexico, and China that created a thin film doped with nitrogen and sensitized with quantum dots. When tested, the new nanocomposite material performed better than predicted--as if the functioning of the whole material was greater than the sum of its two individual components. ... The resulting hybrid material offered a combination of advantages. Nitrogen doping allowed the material to absorb a broad range of light energy, including energy from the visible region of the electromagnetic spectrum. The quantum dots also enhanced visible light absorption and boosted the photocurrent and power conversion of the material.

When compared with materials that were just doped with nitrogen or just embedded with cadmium selenide quantum dots, the nanocomposite showed higher performance, as measured by the "incident photon to current conversion efficiency" (IPCE), the team reported. The nanocomposite's IPCE was as much as three times greater than the sum of the IPCEs for the two other materials, Zhang said.

Physorg