Renewable Energy Technology
Organic Photovoltaic (OPV) devices are a unique type of solar cell. Target applications include:
- BIPV (Building Integrated Photovoltaics)
- Portable power
In OPV the fullerene acts as the n-type semiconductor (electron acceptor). The n-type is used in conjunction with a p-type; either a polymer or other molecule (electron donor). Typically they are blended and cast as the active layer to create what is known as a bulk heterojunction. Fullerenes are used on their own or derivitized to increase their solubility and modify their electronic properties. The most commonly used fullerene derivatives in OPV applications are C60 and C70 PCBM. As the preferred n-type material, fullerenes can comprise up to 75% of the active layer by weight. The potential for increasing device efficiency through novel fullerene chemistries continues to expand. For example, alternative derivatives such as C60 ICBA and C60 OQDM have been shown to increase conversion efficiency by over 40% when compared to C60 PCBM in like systems. These and others are patented by Nano-C.
The OPV field now includes Eight19, Heliatek, Next Energy Technologies, and Solarmer Energy, Inc. And in addition, larger companies are investing in this field on their own as well as in joint projects; among them are BASF, Bosch, Merck, Mitsubishi Chemical, Toshiba and Phillips66.
OPV offers light-weight, flexibility, translucency at a low-cost—attributes vital for BIPV and mobility. OPV panels have the potential to be the most versatile and environmentally friendly PV system. OPV has the highest environmental ROI (energy pay-back) and the highest energy harvesting efficiency (kWh/Wp per day or year). Unlike the older PV technologies, OPV devices absorb light at a wide-range of incident angles and lighting conditions, and therefore they need not be oriented to the sun. In fact, they can be used effectively indoors. Currently, OPV is targeting energy harvesting applications for indoor sensors, chargers, and applications where light-weight/form factor is important. The major commercial application for these light-weight devices will be to integrate them into BIPV and mobility related devices.
Nano-C is a recognized world-class supplier and developer of Fullerene Derivatives for OPV (and OPD). It has partnered with Merck Chemical to develop molecules that uniquely address the needs and requirements for OPV and OPD. Nano-C provides the most efficient n-type electron acceptors for OPV, through its unique ability to modify electronic properties by surface functionalization leading to increased device lifetime and performance with cost-effective chemistries.
The preferred Fuel Cell (FC) for vehicles is the Proton Exchange Membrane Fuel Cell or PEM-FC. In order for PEM-FC to reach their full commercial potential, a number of barriers need to be overcome. Hydrogen infrastructure aside, fundamental improvements are needed in their operating life time, weight and cost. This is possible only through all round improvements in design, engineering and materials systems employed in the construction of PEM-FCs. Nano-C is incubating ‘Clenersys’ (Clean Energy Systems) in collaboration with NuVant Technologies and Northeastern University. Clenersys’ two innovative patent pending products for PEM-FC have the potential to reduce the stack cost, weight and volume for the automotive fuel cell. These products take advantage of the unique properties of Nano-C’s SWCNT.
Corrosion Resistant Bipolar Plates – CORE™
CORE technology is based on a patent-pending ultrathin layer of SWCNT coated on metallic substrates at low temperatures using Nano-C’s proprietary, water based SWCNT inks. CORE takes advantage of SWCNT’s ability to form dense and electrically conducting conformal coatings even at thickness as small as 50-100nm and provide corrosion protection to low-cost stamped metallic bipolar plates. At the atomic level SWCNT coatings mimic the surface of machined graphite bipolar plates which have been the gold standard for PEM over many decades. Graphite bipolar plates have been the preferred choice for optimization and design of Nafion based membranes for Membrane Exchange Assemblies (MEA). As these optimizations have been carried out over last couple of decades, this fact will smooth the adoption and integration of CORE. Early electrochemical tests clearly show that CORE is capable of addressing the corrosion issue at an acceptable cost; enables lower stack weight, cost and volume.
Proton Reservoir and Intrinsic Mobility Enhancement – PRIME™
Nanostructured carbon enabled membranes are a patent pending technology aimed at enhancing the performance of Nafion based MEAs. PRIME is a nano-hybrid based on a SWCNT network chemically modified for proton conduction and a proton conducting polymer. The PRIME concept is similar to inorganic solid acid particle–Nafion hybrids, but overcomes “leach-out,” the main disadvantage in these systems.The unique laminate design electrically isolates proton conduction pathways in the modified SWCNT network. PRIME takes advantage of SWCNT’s unique stability in highly acidic environments and its ability to intercalate solid-acids that provide a novel proton reservoir.
PRIME sets out to eliminate the drawbacks with current Nafion based PEMs: low reliability, dry-out, mechanical failures, swelling, thermal conductivity, electro-osmatic drag and cost. PRIME targets a 20% to 50% increase in energy density, resulting in a corresponding reduction in the weight and volume of the stack delivering comparable power—a coveted goal for military and transportation applications.