A theoretical model for voltage-dependent photocurrent collection in cdte solar cells

Cindy X. Zhao, Ken K. Chin

Research output: Contribution to journalArticlepeer-review


The classic solar cell model assumes that the photo-generated current is a constant, in-dependent of the cell’s output voltage. Experimental data of CdTe solar cells, however, show that the photocurrent collection efficiency decreases with the increase of the cell’s output voltage. In this work, we proposed a theoretical model for the CdTe thin-film cell, which assumes that the loss of photocurrent in the CdTe absorber is primarily due to the minority carrier recombination in the neutral region and at the back contact. By solving the neutral region’s diffusion equation, with proper boundary conditions, we have obtained the analytical expressions of the photocurrent collection efficiency and the cell’s J-V performance. Our theoretical results agree well with the experimental data. According to our theoretical model, the CdTe thin-film solar cell has an optimized p-doping level. A higher doping density may not be always good for a CdTe solar cell due to the reduced depletion width and decreased photocurrent at normal operation voltage, although the higher doping density can improve the open-circuit voltage by increasing built-in voltage.

Original languageEnglish (US)
Article number1615
Issue number6
StatePublished - Mar 2 2021

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Energy (miscellaneous)
  • Control and Optimization
  • Electrical and Electronic Engineering


  • CdTe solar cells
  • Collection loss
  • Photocurrent


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