Faculty
Pushing 50 - High Performance Solar Cell Research
Professor Alexander Balandin and his colleagues are developing high performance solar cells based on quantum dot superlattices (see, e.g., Bao et al., 2004). These new solar cells are targeted for space applications, where photovoltaic efficiency must be as high as possible.This research team continues to improve overall efficiency of this new solar cell, by: 1) tuning the effective band-gap in the structure and using tandem designs; 2) using a three-level concept to improve intermediate band assisted absorption; 3) improving the overall radiation hardness; and 4) extending the overall thermalization times.
Nano Device Laboratory - Balandin Group
Low Cost Organic Solar Cells That 'Cover the World'
In addition to the high performance solar energy technology research based on silicon cells, Professor Mihri Ozkan’s research team is exploring lower cost plastic organic cells (see, e.g., Chaudhary et al., 2007-2008). Figure 6 depicts the performance of their latest hybrid polymer-carbon nanotube solar device fabricated in their laboratory. Layer by layer deposited active layer materials and electrode materials of this solar device has a total thickness of about 2 μm and can be deposited on hard or flexible substrates. The current versus voltage plot of this solar device shows increase in the output current under AM 1.5 sun exposure.
Biomedical Science and Nanotechnology Laboratory
Nanowires for Multi-Junction Solar Cells
Professor Cengiz Ozkan and colleagues are working on large-area solar cells based on nanowire arrays embedded in hole-conducting polymers (Figure 7). The nanowires will enable solar devices to absorb a greater range of the solar spectrum. Nanowires provide a much more efficient way for solar energy conversion via its small lateral dimension (10-200 nm) and large surface area, which enables a highly efficient collection of electrons at the nanowire-polymer interface, whereas their greater length (several microns) will enable maximized absorption of photons. We expect that within the next several years, we can achieve a conversion efficiency of 20%. By December 2008, we will initiate the fabrication of wafer-scale nanowire based devices on conventional silicon and glass platforms using a new metal-organic chemical vapor deposition (MOCVD) system at UCR, which will be crucial for low-cost and large-scale fabrication of solar devices.
Biomaterials and Nanotechnology Laboratory
Breaking the Night Barrier - Molten Salt Storage for Solar Energy
Professors Javier Garay (far right) and Chris Dames are researching improving the efficiency of transporting energy in and out of molten salt storage facilities fed by solar collectors. Garay's research interests also include the broad area of advanced material processing and synthesis with a particular interest in bulk nanocrystalline materials. Dames' specialty is the thermal and electrical properties of nanostructures used for energy conversion. He also works in thermal rectification and modeling of individual nanowires, nanotubes, and graphene.
Advanced Materials Processing and Synthesis Laboratory (AMPS)
Nanostructures and Energy Laboratory
Harvesting Nature's Solar Batteries
Prof. Charles Wyman has long believed that biomass is the most economical way to store solar energy. His research targets biological conversion of abundant, non-food sources of cellulosic biomass to commodity products including ethanol for use as a transportation fuel, an area on which he has focused almost exclusively since 1980, with emphasis on pretreatment and enzymatic hydrolysis. In his view, biofuels present the only sustainable option to reduce our petroleum dependence for liquid transportation fuels on a large scale, and modern biotechnology will dramatically reduce costs of making cost-competitive fuels and chemicals from biomass with tremendous environmental, economic, and strategic benefits.
Cellulosic Ethanol Pretreatment Laboratory
Engineering Living Light Sources
Chemiluminescence has evolved numerous times in invertibrates, vertibrates, as well as aquatic and terrestrial animals. David Kisailus (far right) studies the structures and processes of bioluminescence to discover solutions for energy storage and conversion materials (photovoltaics, fuel cells, batteries). In order to design and synthesize nano-scaled materials with desired properties, an understanding of the interfacial phenomena controlling nucleation and growth is necessary. Valentine Vullev studies charge-transfer properties of biomimetic and bioinspired systems for organic electronics and solar-energy-conversion applications. Charge recombination is a source of considerable energy loss in solar-energy-conversion devices. Vullev is working to investigate and develop systems that mediate efficient photoinduced charge transfer and suppress the undesired back charge transfer.
Bio-inspired Nanomaterials Laboratory
Biomolecular and Device Engineering Laboratory
Following Nature's Lead
Elaine Haberer studies nanostructured, bio-templated
materials for energy applications. Biological templates are able to recognize,
selectively bind, nucleate, and grow inorganic materials with novel architectures
under ambient, environmentally-benign conditions, thus providing the potential
for both enhanced device performance and substantially reduced manufacturing
costs.
Thermal Energy Storage On the Porous Plain
Professor Kambiz Vafai researches questions of heating and cooling in the world of porous materials. His research interests are in heat transfer and fluid flow modeling such as thermal design and modeling (computational and experimental), feasibility, optimization and parametric studies for various engineering applications. In particular, he has done extensive investigations in the area of thermal design and modeling (computational and experimental), power electronics modeling and design, cooling enhancement investigations, feasibility, optimization and parametric studies for various engineering applications.