Rachael Greenhalgh

Cohort 3



Improved efficiency of thin film Photovoltaic devices

Collaboration with the National Renewable Energy Laboratory (NREL) and Colorado School of Mines (CSM) in the United States has shown the benefit of using Rapid Thermal Processing (RTP) to anneal back contacts for thin film CdTe photovoltaic (PV) devices. An RTP system has been recently installed at the CREST Laboratories at Loughborough. This project will explore the benefits of using RTP for annealing absorbers, back contacts and buffer layers in thin film devices. Initial experiments have shown the promise of using RTP by increasing the photo-voltage of thin film CdTe devices.

The advantage of RTP processing appears to be its fast ramping and short cooling times which ensure tight control of the process. We will also use RTP to control the selenization process for thin film CIGS devices. We have recently succeeded in fabricating CIGS devices using solution based processes using novel solvents. We are working with Nanoco Technologies plc aiming to scale up modules using Nanoco’s CIGS nanoparticle technology.

The project will initially focus on establishing the range of operating conditions made possible by RTP. The student will then study the use of RTP for annealing important layers in inorganic thin film PV. The student will use a battery of techniques to assess changes in micro-structure and make comparisons with conventional annealing in an oven. The following thin film annealing processes will be investigated:

  • Annealing of back contacts for thin film CdTe and CIGS.
  • Annealing and microstructure of thin film CdTe.
  • Selenization of CIS and CIGS PV devices
  • Since this work was started through a collaboration with CSM, we will arrange for the student to spend 3 months in Colorado.