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Next generation of PV-PEC tandem cells for green hydrogen generation (NanoGRHYN)

Integration of III-Nitrides with the silicon solar cell technology for highly efficient generation of green hydrogen with long term stability.

The aim of this project is the demonstration of the next generation of photovoltaic-photoelectrochemical (PV-PEC) tandem cells for green hydrogen generation via water splitting.

The project will rely on the integration of III-Nitrides with silicon technology. The photovoltaic cell will be a multicrystalline silicon (m-Si) solar cell and the InGaN/GaN nanowires will be the front photoelectrode. This tandem approach can lead to high solar-to-hydrogen conversion efficiencies (~26%) for optimized bandgaps of the semiconductors (1.1 for the solar cell and 1.6-1.8 eV for the photoelectrode). Photo-electro-chemical (PEC) cells have proven to be a successful approach for hydrogen generation via water splitting.

Major challenges we will face during this project are the growth of InGaN/GaN NWs on multicrystalline silicon, the Mg-doping of the InGaN of high In-content, the prevention of the photoinduced corrosion of the structure, especially at the heterointerface between both absorbers, and the resistive losses due to the current matching between both cells. All of them will be addressed in this project by theoretical study and simulation and by experimental realisation.

In this project we are focused on the development of the photocathode for the PV-PEC tandem cell. Within this tandem arrangement, the InGaN top absorber would absorb photons of energies above the silicon bandgap, without compromising the absorption of the Si solar cell.  This design is simpler and cheaper than other semiconductor device designs currently used in PEC cells since it would make use of the cheap and well established multicrystalline silicon technology.

The project team

Lead researcher

Dr Victor Hernández

Research Associate