Deposition and Patterning of CZTS as a Light Absorbing Material for Solar Applications

Open Access
Author:
Nicol, Katherine Tait
Area of Honors:
Energy Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Jeffrey Brownson, Thesis Supervisor
  • Sarma V Pisupati, Honors Advisor
Keywords:
  • solar energy
  • photovoltaics
  • building integrated photovoltaics
  • photolithography
Abstract:
Building integrated photovoltaics (BIPVs) have enormous potential for the future as a way to incorporate solar PV devices into building materials, thereby reducing the overall installation cost of solar projects. Using BIPVs as a replacement for conventional windows has a unique problem of retaining transparency and visibility through the window while absorbing some of the sunlight entering the window. This investigation explores depositing copper zinc tin sulfide (CZTS), a light absorbing semiconductor material with potential applications in thin film solar cells, into etched channels simulating an etched window. Photolithography and deep reactive ion etching was successfully used to generate straight anisotropic channels of the desired design and width. While some channels contained impurities, most were clearly etched straight channels with few impurities. Using a doctor blading with a CZTS colloid suspension in ethylene glycol, the most concentrated channel depositions were covered with approximately 70% CZTS. The average deposition amount was significantly less with depositions covering as little as 27% of the channel. A paste of CZTS with Triton X was then prepared to reduce surface tension and increase the precursor concentration; this produced depositions containing over 30% more CZTS in the channels. Using this deposition technique, channels on average contained 80% CZTS. It is recommended that in the future, the surface effects of depositing a conducting oxide layer prior to the CZTS should be investigated. Also, ink jet printing should be explored as an alternative deposition method.