Plasmonically Enhanced Solar-To-Fuel Conversion: Two-Photon Photoatalytic System(3/3)

Clean energy plays a critical role in the sustainable developments of our country. Green chemistry toproduce energy carriers (such as H2 as fuel) can provide a way to mitigate environment impacts caused bytraditional production processes. In particular, solar-to-fuel conversion is one of the options. However, thisphotoelectrochemical/photocatalytical process, typically the solar hydrogen generation from water splitting,still suffers from low conversion efficiencies. This can be attributed to low photo-excited electron-holeseparation, short carrier diffusion length, low absorption, and slow reaction kinetics at thesemiconductor/electrolyte interface. We propose this three-year proposal to tackle these problems, based onour experience on wet-chemical synthesis of photo-active materials and photoelectrochemical systems. Inaddition to the fundamental material properties, such as band gap, band position, conduction types, andcorrosion, matching of the energy bands, design of tandem cell structures, and charge carrier transportkinetics and pathways are also important to the final solar-to-fuel conversion efficiency. One of the focuses ofthis proposal is the incorporation of the gold-silver nanoshells (AuNS) that exhibit a tunable surface plasmonresonance (400-1000 nm), in order to facilitate charge separation of photo-excited carriers. Our preliminarystudy showed that the coupling of the SPR of AuNS and absorption of photocatalyst, as well as the distancebetween these two materials, has a decisive effect on the hydrogen production rate. We will extend ourprevious studies and synthesize a well-defined core-shell structure, with controllable composition and layerthickness. Different dielectric materials will be deposited on top of the AuNS to investigate the dielectric andinterlayer thickness effects. Furthermore, layered architecture and two-photon reactor system will bedesigned, and the charge carrier transport properties across the interfaces will be thoroughly studied to gaininsights into the physics of photoelectrochemical systems. Through a series of systematic studies, weanticipate that the composite reaction system can enhance the electron-hole separation, reduce the darkcurrent (leakage current), and increase the reaction kinetics and stability.A. Collect the materials properties of various photocatalysts synthesized in our lab to create a materialsdatabase.B. Prepare photoanode and photocathode based on the material properties mentioned above. Design andfabricate a two-photon photoelectrochemical reaction system.C. Study the AuNS@dielectrics@photocatalyst core-shell structure for enhanced solar-to-fuelconversion.