Sunstone® Photovoltaics

Intelligent Material Solutions, Inc. realizes the importance of finding scalable and efficient technologies to increase our renewable energy capabilities.  Sunstone PV® is a novel rare earth-based photovoltaic architecture utilizing advanced nano-synthetic technologies integrating plasmonically enhanced rare earth nanocrystals into high efficiency photovoltaic devices as well as films that can be applied to commercially available PVs for improved solar cell performance. We are focusing significant efforts around advanced nano-manufacturing techniques enabling low cost, high volume production of our technologies to ensure widespread, low cost energy available throughout the world.
 
Photovoltaics (PV), is unique since the energy from the sun can be directly converted into electricity without the need for moving parts or ongoing and costly maintenance, yet solar energy still only contributes approximately 1% of all renewable sources. One reason for this is the relatively long payback time of a solar module compared with other energy sources. For solar energy to be competitive in the modern energy market, it must be efficient and cheap, the focusing requirements for a third generation PV device.  First generation bulk crystalline silicon devices currently dominate the commercial PV market and utilize mature technologies that have benefited from more than half a century of research and development. The transition from first to ‘thin-film’ second generation technology has been slow since thin films must match or exceed the reliability and, cost/performance ratio of established Si crystalline technologies. Both these technologies suffer from fundamental bandgap losses which can only be overcome using novel materials and device configurations. We believe that Sunstone PV® Nanocrystals will enable a device with energy conversion efficiencies over the theoretical 31%, approaching values closer to the thermodynamic limit of 93% efficiency.


Sunstone® PV Nanocrystals can absorb wavelengths that fall outside of the usable portions of the electromagnetic spectrum by conventional solar PV devices and emit in the wavelength sensitive regions of any PV device.  The image below depicts rare earth upcovnerting nanocrystals deposited onto the surface silicon wires of a photovoltaic device.  The adjacent chart depicts the solar energy not absorbed by the conventional PV devices.  By incorporating our technology into these devices we can significantly improve the cost effectiveness of solar energy as a renewable resource.
 
1352 W/m2 Solar Radiation (UV-NIR) received on the Earth’s surface
  • 192W/m2 (14%)  in UV region,
  • 520W/m2 (38.4%) in the visible
  • 640W/m2 (47.3%) in the infrared region

Only 38% of the visible solar radiations is absorbed by Si, effective conversion of the remaining 62% photons from the UV and IR region into the Si visible-NIR response region can have drastic improvement in solar cell efficiency.  
 
Modern day solar cells do not fully utilize the solar spectrum and suffer from fundamental optical losses. High energy photons are lost as thermal energy within the device and low energy photons pass through. By utilizing the multi-photon mechanisms of down-conversion (photon splitting) of high energy photons and up-conversion (combining the energies) of low energy photons the incident solar spectrum can be manipulated to better match the absorption properties of the semiconductor and therefore optically enhance the efficiency of the solar cell.  The spectral curves show a sample of rare earth nanocrystal emissions overlapping with current PV absorption curves.


 
Multi-photon, Sunstone® PV nanocrystals have been developed and are being integrated with plasmonically active nanomaterials and incorporated into a variety of photovoltaic device technologies to determine the ideal final PV architecture.
 
Research Focus
Addressing the fundamental efficiency losses of semiconducting photovoltaic devices. By utilizing multi-photon nanocrystals in conjunction with a semiconductor photovoltaic device, it may be possible to utilize the sun’s energy more efficiently.  Enhancing the efficiency of existing solar cell technology could rapidly increase PV into the fledging renewable energy market.
 
Cutting edge research. Our pioneering application of rare-earths for multi-photon materials for photovoltaics is at the forefront of the field. An in-depth understanding of current limiting photovoltaic processes and resources of an electronic materials research facility offers a unique opportunity to cross-disciplines and remain leaders in the topic of multi-photon third generation photovoltaic research.