About the project
The main focus of this project is on implementation of micro-engineering and nanotechnology for formation of heterostructures based on oxide thin films and metal-oxide nanostructures with properties optimized for PV. Besides the bulk of the thin films, interfaces within such solar cells play a crucial role both during manufacturing and operation. Their complex structure demands synergy between processing, characterisation and theory and should be probed at the atomic level in order to understand the mechanisms governing their formation and function. We intend to address the local atomic arrangement of the materials by high resolution electron microscopy and nanoscale electron diffraction. Their electronic structure will be probed by high spatial resolution electron energy loss spectroscopy and electron holography together with x-ray and ultraviolet photoelectron spectroscopy. These techniques have high spatial and/or energy resolution, and are able to probe both the bulk film and the interfaces.
The materials will be also fully characterised optoelectronically. The main theoretical tool to be used is density functional theory (DFT), which can predict atomistic structures and electronic structures without any adjustable parameters. This will be complemented with more accurate methods like hybrid functional and GW if e.g. precise predictions of band gaps are required.
We intend to start our studies with the ZnO/Al and ZnO/Ag systems by exploiting consortiums experience in both processing and characterisation of similar systems. Studies of the novel ZnO/Ag2O and ZnO/Cu2O structures will follow. The results will be demonstrated by developing first a Si-based solar cell with ZnO(Al) antireflective coating followed by the development of a multijunction solar cell with oxide-based front cell and Si-based back cell.
Objectives
The primary objective of HeteroSolar is to contribute in the development of new generation oxide based solar cells with reduced cost and improved efficiency, by understanding the structure of systems consisting of thin films and interfaces and by demonstrating the results with "proof of concept" devices.
The secondary objectives are:
- Increased knowledge for oxides as novel materials in next generation solar cells
- Systematic studies of interfacial chemistry and morphology as a function of processing
- Insight into the relationship between interfacial atomic arrangement and structural defects with optoelectronic properties
- Development of processing diagnostics tools and predictive methodologies by combination of parameter-free calculations and experimental observations
- Development of demonstration devices based on ZnO:Al/Si and multijunction solar cell with oxide-based front cell and Si-based back cell
Financing
Cooperation
This project is a collaboration between these two partners:
- SINTEF (coordinator)
- UiO