High-Efficiency, High-Power Density III-V Multijunction Solar Cells on Si and Hybridsilr Navy STTR FY2014.A Sol No.: Navy STTR FY2014.A Topic No.: N14A-T003 Topic Title: High-Efficiency, High-Power Density III-V Multijunction Solar Cells on Si and Hybridsilr Proposal No.: N14A-003-0249 Firm: NanoSonic, Inc. 158 Wheatland Drive Pembroke, Virginia 24136 Contact: Hang Ruan Phone: (540) 626-6266 Web Site: http://www.nanosonic.com Abstract: This DOD Phase I STTR program would develop III-V multijunction based solar cells, using Virginia Tech's InGaP/GaAs/InGaAs multijunction cells technique in combination with NanoSonic's pioneering Hybridsilr antireflection copolymer nanocomposite materials, which afford high levels of antireflection, temperature and abrasion resistance, impact durability and hydrophobicity (self cleaning). Such an approach to form flexible PV materials and devices offers advantages over dye-sensitized solar cells (DSSC) and hydrogenated amorphous silicon based flexible PV devices, in that much higher energy efficiency can be obtained on flexible substrates with large area manufacturing and processing. The central theme of our proposal is to demonstrate heterogeneously integrated high efficiency III-V multijunction solar cells on cheaper, larger diameter and readily available Si substrate as well as solar cells through epitaxial release from Si. The released multijunction structures will be transferred to NanoSonic's highly transparent, super lightweight and mechanically robust Hybridsilr materials to be integrated into flexible PV devices. NanoSonic's Hybridsilr composites will be used not only as the substrates but also the antireflection coatings to enhance the device efficiency. Benefits: Achieving high-efficiency and lightweight solar cells has been the key objective for solar power systems for small unmanned aerial vehicles (SUAVs). The dominant technology in use in the flexible photovoltaic world is hydrogenated amorphous silicon due to the limited manufacturing temperature of plastic substrates. Such PV devices have much lower energy conversion efficiency and shorter lifetime compared to crystalline III-V multijunction based PVs. The integration of III-V multijunction structures with super light weight, highly transparent and mechanically robust polymeric materials will enable the PV devices to be attached or made into the conformal substrates to fully use the solar energy. Return