Heterojunction structures have already reached the highest efficiencies for silicon-based solar cells. Furthermore, it is a low-temperature technology well-suited to use thinner wafers. Since heterojunction structures include surface passivation, they can be implemented as fullarea contacted devices. By contrast, traditional high-efficiency silicon solar cells need complex patterning steps. So many pros do not serve for a high market share, which is still widely captured by a rather traditional diffusion technology. Some reasons hindering the growth of the heterojunction technology are the use of relatively complex deposition systems, besides hazardous gas precursors. This project explores nonconventional heterojunction structures. There is a variety of materials able to selectively extract one type of charge carrier from a silicon base. They are electron or hole transport layers, which are referred in the literature as selective contacts. The use of complementary selective contacts on a silicon absorber results in an efficient solar cell. The literature on this field is new, just from the last two years, but reported efficiencies are already impressing. These materials are readily available and they can be deposited by thermal evaporation or sputtering. The project also aims to investigate alternatives for the silicon absorber. The traditional technology is based on silicon wafers, which cost around a 40% of the photovoltaic module. Sawing thinner wafers from an ingot is still a challenge. Alternatively, we propose nonconventional absorbers based on recrystallized silicon layers. This activity will focus on two fields: optimization of silicon layers grown at high deposition rates and parameterization of a laser recrystallization step. The bulk passivation of multicrystalline silicon substrates will be also considered in the project. Besides nonconventional solar cells, the project will study novel laser-assisted fabrication processes. First, an industrially feasible metallization step for low-temperature structures. This will be based on the laser-induced-forward-transfer of metallic pastes. A laserannealing process will also circumvent the high-temperature step for a conventional firing. The last laser-assisted process will be related to patterning, mainly for interdigitated-back-contact solar cells. In this sense, laser-ablation of materials used during the project will be studied for a high-resolution patterning. The project innovates in three main fields: alternative materials for photovoltaic applications, novel device structures and fabrication technologies. The consortium founds its proposal on a sustained collaboration in several coordinated projects. The proposed research activity is well-founded on preliminary studies and bibliographic reports, which give us confidence for a successful development.
Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016
Programa Estatal de I+D+i Orientada a los Retos de la Sociedad
Retos de Investigación: Proyectos de I+D+i
Gobierno De España. Ministerio De Economía Y Competitividad, Mineco
García, R.; Garcia, E.; Montero, D.; Olea, J.; Prado, Á. del; Martil, I.; Voz, C.; Gerling Sarabia, L.; Puigdollers, J.; Alcubilla, R. Solar energy materials and solar cells Vol. 185, num. October 2018, p. 61-65 DOI: 10.1016/j.solmat.2018.05.019 Date of publication: 2018-10-01 Journal article
Zafoschnig, L.; Ortega, P.; Martin, I.; Masmitja, G.; Lopez, G.; Alcubilla, R. European Photovoltaic Solar Energy Conference and Exhibition p. 653-656 Presentation's date: 2018-09-24 Presentation of work at congresses