Extended description of tunnel junctions for distributed modeling of concentrator multi-junction solar cells

• Published in: Solar energy materials and solar cells 2011-09, Vol.95 (9), p.2693-2697
• Main Authors: Espinet, P., García, I., Rey-Stolle, I., Algora, C., Baudrit, M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Computer simulation; Concentrators; CPV; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Energy; Exact sciences and technology; Mathematical models; Multi-junction solar cells; Natural energy; Photoelectric conversion; Photovoltaic cells; Photovoltaic conversion; Solar cells; Solar cells. Photoelectrochemical cells; Solar collectors; Solar concentrator; Solar energy; Solar thermal conversion; Spreading; Three dimensional; Tunnel junction; Tunnel junctions
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2011.05.009

One of the key components of highly efficient multi-junction concentrator solar cells is the tunnel junction interconnection. In this paper, an improved 3D distributed model is presented that considers real operation regimes in a tunnel junction. This advanced model is able to accurately simulate the operation of the solar cell at high concentrations at which the photogenerated current surpasses the peak current of the tunnel junction. Simulations of dual-junction solar cells were carried out with the improved model to illustrate its capabilities and the results have been correlated with experimental data reported in the literature. These simulations show that, under certain circumstances, the solar cell's short circuit current may be slightly higher than the tunnel junction peak current without showing the characteristic dip in the J– V curve. This behavior is caused by the lateral current spreading toward dark regions, which occurs through the anode/p-barrier of the tunnel junction. [Display omitted] ► A 3D distributed model is presented that considers real operation regimes in a tunnel junction. ► Simulations were performed and correlation with experimental data was undertaken. ► Simulations show a non-negligible current spreading through the anode of the tunnel junction. ► Short circuit current may be higher than the tunnel junction peak current without efficiency lost.