Transient metastable behavior caused by magnesium-doped zinc oxide emitters in CdSeTe/CdTe solar cells
Metastable behavior in highly efficient MZO/CdSeTe/CdTe solar cells has been reported previously. Different preconditioning procedures have been studied that are used to recover the performance of the devices. 11 wt% of MgO content in the MZO layer has shown to give optimized photovoltaic parameters in the device compared to other MZO compositions. J – V characteristics before preconditioning of the devices with higher MgO content show an “ S ” shaped behavior, which is removed during preconditioning. However, this recovery remained only for 3 days while the devices were stored under vacuum in the dark. Temperature-dependent J – V and capacitance measurements before and after preconditioning revealed the presence of recombination centers and defect levels at the MZO/absorber interface. Previous studies have shown degradation of MZO occurring if the layer is exposed to ambient atmosphere. Hall effect measurements on the MZO films showed no significant changes after any preconditioning or CdCl 2 treatment. Secondary-ion mass spectrometry images show diffusion of oxygen from the MZO layer into the CdSeTe region after CdCl 2 treatments. This likely enables the MZO to function as a buffer layer since it will increase the carrier concentration due to the formation of oxygen vacancies. As-deposited MZO thin films are insulating. However, the oxygen vacancies in the MZO layer also increase its reactivity and instability.
Funding
SOLplus - Improved Energy Efficiency of Solar PV Systems via Low Surface Energy Coatings
Engineering and Physical Sciences Research Council
Find out more...History
School
- Mechanical, Electrical and Manufacturing Engineering
Research Unit
- Centre for Renewable Energy Systems Technology (CREST)
Published in
IEEE Journal of PhotovoltaicsVolume
13Issue
3Pages
391 - 397Publisher
Institute of Electrical and Electronics Engineers (IEEE)Version
- VoR (Version of Record)
Rights holder
© The Author(s)Publisher statement
This is an Open Access Article. It is published by IEEE under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/Acceptance date
2023-01-30Publication date
2023-03-01Copyright date
2023ISSN
2156-3381eISSN
2156-3403Publisher version
Language
- en