SLICE · Surface Lifetime Investigation for Characterization and Enhancement of passivating contacts in c-Si solar cells
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2021-04-01 → 2023-05-21
- EU contribution
- €191,149
- Participants
- 1
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Surface Lifetime Investigation for Characterization and Enhancement of passivating contacts in c-Si solar cells
One key action to mitigate the adverse impacts of climate change is transitioning to sustainable energy production, notably through photovoltaic (PV) power generation. PV technologies based on crystalline silicon (c-Si) currently represent ∼95% of the global market and will thus be the main driving force toward the expected growth of worldwide PV installations to the multi-terawatt scale. Lately, further increase of the conversion efficiency of industrial mainstream c-Si solar cells has relied on the integration of passivating contacts based on a highly-doped polycrystalline silicon (poly-Si) layer on top of a thin silicon oxide (SiOx) buffer layer (so-called “poly-Si contacts”). The overall objective of SLICE was to elucidate the interrelation between the functional properties of poly-Si contacts (especially surface passivation) and their fabrication process in order to guide the developments of better surface passivation and ultimately c-Si solar cells with higher efficiency. Throughout the project, we developed novel methodologies that enabled the identification of the first order limitation to reaching poly-Si contacts featuring both high surface passivation and good electrical properties. Based on this key finding, we optimized the fabrication process to eventually demonstrate poly-Si contacts providing higher and better thermally stable surface passivation.
Data: CORDIS, © European Union
Project objective
In the context of high-efficiency solar cells based on crystalline silicon (c-Si), the integration of passivating contacts between the metal electrodes and the c-Si substrate has been identified as the next step to further improve the photovoltaic conversion efficiency. Passivating contacts consisting in a highly-doped poly-crystalline silicon (poly-Si) layer on top of a thin layer of silicon oxide (SiOx) offer the most promising approach to bridge the gap between device efficiencies in R&D and those in production. However, their development has mainly proceeded through “trial and error” so far, resulting in a limited understanding of their underlying working principle. More specifically, the surface passivation provided by poly-Si contacts is a combination of different mechanisms, among which the limiting one is still unclear due to: i) the interplay between these different mechanisms and ii) the challenge of characterizing thin-film stacks with features to the nanometric scale. Moreover, p-type poly-Si contacts, which are of prime interest since they could provide an alternative to the conventional contact at the rear side of mainstream p-type c-Si solar cells, have so far demonstrated lower passivation properties than their n-type counterparts, the fundamental reason for this difference remaining unclear. Within the SLICE project, a dedicated methodology based on lifetime spectroscopy scpecially adapted to the c-Si surface will be applied to identify electrically active defects limiting the lifetime of charge carriers at the interface between poly-Si contacts and the c-Si. The investigation of different passivating thin-film stacks of iterative complexity will enable to relate their properties to their fabrication process. The insights gained from this original characterization of interfacial defects will support the fabrication of better passivating poly-Si contacts and ultimately solar cells with higher efficiency.
Original text from CORDIS.
Participants
- ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE · LausanneCoordinatorSwitzerland
Links
Data: CORDIS, © European Union