Aqueous Design & Electronic Structure Engineering of New Materials for Solar Energy Conversion

Time: Wednesday, April 25, 2018 - 10:30am - 11:30am
Type: Seminar Series
Presenter: Dr. Lionel Vayssieres; International Research Center for Renewable Energy (IRCRE), Xi’an Jiaotong University
Room/Office: Becton 035
Becton Seminar Room
15 Prospect Street
New Haven, CT 06511
United States

Department of Chemical & Environmental Engineering Seminar

Aqueous Design & Electronic Structure Engineering of New Materials for Solar Energy Conversion

Dr. Lionel Vayssieres
International Research Center for Renewable Energy (IRCRE)
Xi’an Jiaotong University

The demand of low-cost and highly efficient materials has become a major challenge scientists are facing to answer crucial contemporary issues such as clean alternative energy resources for a safer and cleaner environment. One of the promising alternatives for the transition of fossil fuel-based energy to a clean and renewable one relies on the widespread implementation of solar energy systems[1], yet the high cost of energy production and low-energy of currently used material combinations pose an intrinsic limitation. In this context, new materials development is required to achieve the necessary crucial increase in power generation and conversion efficiency. The necessity of materials development which is not limited to materials that can achieve their theoretical limits, but makes it possible to raise these limits by changing the fundamental underlying physics and chemistry is critical. Low cost purpose-built materials with optimized structure and properties combined with inexpensive large scale manufacturing methods will play a decisive role in the success of renewable energy systems. However, fabricating large areas of such materials is a daunting challenge.

Novel smarter and cheaper fabrication techniques and, just as important, better fundamental knowledge and comprehensive understanding of their properties using nanoscale phenomena such as quantum confinements to create multi-functional structures and devices is the key to success. Such concepts will be demonstrated by the thermodynamic modeling, low-cost aqueous design and fabrication of highly oriented crystalline arrays of metal oxide quantum dots and rods-based structures and devices with controlled orientation, size and shape onto various substrates designed at multiple scales by aqueous chemical growth at low-temperature[2] along with the in-depth study of their electronic structure and quantum confinement effects performed at synchrotron radiation facilities[3] as well as their applications for sustainable solar energy conversion such as solar fuels[1] and photovoltaics.

Wednesday, April 25, 2018 at 10:30AM
Becton Seminar Room MC 035

Refreshments at 10:00AM

[1]X. Guan et al. Efficient unassisted overall photocatalytic seawater splitting on GaN-based nanowire arrays, J. Phys. Chem. C 2018, in press; J. Su et al, Stability and performance of sulfide-, nitride-, and phosphide-based electrodes for photocatalytic solar water splitting, J. Phys. Chem. Lett. 2017, 8, 5228; A place in the sun for artificial photosynthesis? ACS Energy Lett. 2016, 1, 121; Y. Tachibana et al. “Artificial photosynthesis for solar water splitting”, Nat. Photon. 2012, 6, 511; C.X. Kronawitter et al. A perspective on solar-driven water splitting with all-oxide heteronanostructures, Energy Environ. Sci. 2011, 4, 3889; On solar hydrogen & nano- technology, L.Vayssieres ed., Wiley 2009, pp 1-704.
[2]L.Vayssieres, Growth of arrayed nanorods and nanowires of ZnO from aqueous solutions, Adv. Mater. 2003, 15, 464; On the design of advanced metal oxide nanomaterials, Int. J. Nanotechnol. 2004, 1, 1; On the thermodynamic stability of metal oxide nanoparticles in aqueous solutions, Int. J. Nanotechnol. 2005, 2, 411; On the effect of nanoparticle size on water-oxide interfacial chemistry, J. Phys. Chem. C 2009, 113, 4733; Y.Wei et al. Spontaneous photoelectric field-enhancement effect prompts the low cost hierarchical growth of highly ordered heteronanostructures for solar water splitting, Nano Res. 2016, 9, 1561.
[3]L.Vayssieres et al. Size effect on the conduction band orbital character of Anatase TiO2 nanocrystals, Appl. Phys. Lett. 2011 99, 183101; 1D quantum-confinement effect in α-Fe2O3 ultrafine nanorod arrays, Adv. Mater., 2005, 17, 2320; J. Engel et al. In-situ electrical characterization of Anatase TiO2 Q-dots, Adv. Func. Mater. 2014, 24, 4952; C.X. Kronawitter et al. TiO2–SnO2:F interfacial electronic structure investigated by soft x-ray absorption spectroscopy, Phys. Rev. B 2012, 85, 125109; Titanium incorporation into hematite photoelectrodes: Theoretical considerations and experimental observations, Energy Environ. Sci. 2014, 7, 3100; Electron enrichment in 3d transition metal oxide hetero-nanostructures, Nano Lett. 2011, 11, 3855; On the interfacial electronic structure origin of efficiency enhancement in hematite photoanodes”, J. Phys. Chem. C 2012, 116, 22780; On the orbital anisotropy in hematite nanorod-based photoanodes, PCCP 2013, 15, 13483; M.G. Kibria et al. Atomic-scale origin of long-term stability and high performance of p-GaN nanowire arrays for photocatalytic overall pure water splitting, Adv. Mater. 2016, 28, 8388.