Symmetric dopant-free Si solar cells enabled by TiOx nanolayers

Solar photovoltaic devices are a promising technology underpinning the world's renewable energy transformation.

In the paper 'Symmetric dopant-free Si solar cells enabled by TiOx nanolayers: an in-depth study on bipolar carrier selectivity' published in Advanced Science, the authors* demonstrate a symmetric dopant-free crystalline Si solar cell, using amorphous TiOx as both front and rear contact.  

Ex-situ and in-situ X-ray photoelectron spectroscopy measurements revealed that the bipolar carrier selectivity of TiOx is associated with the different amount of negative fixed charge generated during the nanolayer growth in atomic layer deposition.

The findings in this paper pave the way for a deeper understanding of the charge generation mechanism and chemistry at the Si/metal oxide interfaces.

*The authors were from the National Institute of Advanced Industrial Science and Technology (Japan), this department and the Graduate School of Engineering (Japan).