Theoretical efficiency limits of a 2 terminal dual junction step cell

• Main Authors: Hadi, Sabina Abdul (Author), Milakovich, Tim (Contributor), Bulsara, Mayank (Contributor), Fitzgerald, Eugene A. (Contributor), Hoyt, Judy L. (Contributor), Nayfeh, Ammar (Author), Polyzoeva, Evelina Aleksandro (Contributor)
• Other Authors: MIT Materials Research Laboratory (Contributor), Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science (Contributor), Massachusetts Institute of Technology. Department of Materials Science and Engineering (Contributor), Massachusetts Institute of Technology. Microsystems Technology Laboratories (Contributor)
• Format: Article
• Language: English
• Published: Institute of Electrical and Electronics Engineers (IEEE), 2016-05-23T01:15:19Z.
• Subjects: Article
• Online Access: Get fulltext

 In this paper we present theoretical analysis for upper efficiency limit of a novel 2 terminal dual junction stepcell. Results show that step cell design relaxes bandgap requirements for efficient tandem cell. While conventional tandem cell with optimized bandgap combination (1.64 / 0.96 eV) has the highest efficiency (45.78 %), the step-cell design provides significant efficiency improvement for cells with non-optimized bandgap values. Efficiency upper limit for Si based step-cell with top cell bandgap equal to 1.41 eV (~ GaAs), efficiency upper limit increases from ~21% in conventional tandem cell to 38.7% for optimized step-cell design. Step-cell design provides opportunity for wider selection of materials used in tandem solar cell applications.