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Non-conventional silicon heterojunction solar cells

Total activity: 4
Type of activity
Competitive project
Funding entity
Funding entity code
157.300,00 €
Start date
End date
alta eficiencia, bajo coste, célula solar, heterojunction, heterounión, high-efficiency, laser-processing, low-cost, photovoltaic technology, procesado láser, recristalización, recrystallization, silicio, silicon, solar cell, tecnología fotovoltaica
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.
Adm. Estat
Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016
Call year
Funcding program
Programa Estatal de I+D+i Orientada a los Retos de la Sociedad
Funding call
Retos de Investigación: Proyectos de I+D+i
Grant institution
Gobierno De España. Ministerio De Economía Y Competitividad, Mineco


Scientific and technological production

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