Advanced Lead Selenide Quantum Dot Solar Cells Utilizing the Light and Carrier Collection Management Architecture

Open Access
Author:
Forgie, Kevin Douglas
Area of Honors:
Engineering Science
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Stephen Joseph Fonash, Thesis Supervisor
  • Joseph Lawrence Rose, Honors Advisor
  • Judith A Todd, Faculty Reader
Keywords:
  • Solar cells
  • Photovoltaics
  • Thin-films
  • Quantum dots
  • Computer modeling
  • Photonics
  • Light management
  • Lead selenide
Abstract:
Quantum dot (QD) thin-film solar cells are an exciting new area of solar cell research, as QDs offer the ability to “fine tune” their band gap to suit a particular application. Previous work with QD solar cells has focused on simple planar device structures, with overall efficiencies remaining low compared to other cell types. This work, for the first time, implements QDs as the active absorber material in a nano-structured solar cell. Using lead selenide (PbSe) QDs in the Light and Carrier Collection Management (LCCM) architecture, this thesis studies the performance improvements in LCCM cells over planar cells via computer modeling and numerical analysis. The LCCM uses a periodic array of nano-elements to produce both enhanced light trapping/absorption and photocarrier collection. Superior light capture and improved photogenerated carrier collection are shown to be attainable with ultra-thin QD layers. PbSe QD LCCM devices give, on average, a 40% improvement in short-circuit current density (JSC) and a maximum improvement of 57%, compared with corresponding planar devices. Furthermore, the LCCM architecture was able to increase PbSe QD absorber mass utilization by up to 18%. LCCM unit cell dimensions and various materials systems were studied to produce an optimal design for maximum cell performance. The results of this research will help provide insight into more complex designs for QD solar cells that can attain significantly higher efficiencies.