In the first part of the meeting, two of the partners REC Solar and NorSun gave us an update on the ongoing expansions for sustainable silicon production for solar cells. Trine Kopstad Berentsen from Solenergiklyngen presented the status of PV installations and market in Norway. She showed that the amount of PV installations is growing, with a 51.4 MWp new installed PV in 2019, more than double of what was installed in 2018.

The second part of the meeting was divided in four parallel sessions, each oriented towards the four different research areas.

Session 1 – Sustainable silicon feedstock production

The session about sustainable solar silicon production had five talks from the research partners. Mengyi Zhu, PhD from NTNU, presented his results on developing a sustainable silicon purification process based on Si doping by Mg and acid leaching which yields a high Si recovery. He also showed his experimental results on Si-kerf recycling via a slag refining process. This work is complemented by the work of Kai Tan, senior research scientist at Sintef, who presented his computational thermodynamics results about the ternary Si-Ca-P, Si-Mg-P, and quaternary Si-Ca-Mg-P systems. He also presented recent results JMAk isothermal kinetic model and also establishment of TTT diagrams for studying the precipitation of impurities in the phases upon solidification of doped silicon. Azam Rasouli, PhD from NTNU, presented her research project about the metallothermic reduction of silica, and some theoretical results. Anjitha Geetha, researcher from IFE, presented her research work on modelling of mono-silane decomposition that is important for the chemical route for solar silicon production. Alexander Azarov, PostDoc at UiO, had a talk about the SIMS technique in characterization of Si and Mg-doped silicon and the distribution of B and P impurities in the phases. The presentations were all interesting, in particular for the industrial partners and audience were engaged on asking questions and discuss the research results

Session 2- High performance silicon ingots and wafers.

The four presentations represented the broadness of the high level scientific work going on in this field. Marisa Di Sabatino Lundberg (NTNU) presented the results from the characterization of crucibles made of different quartz sand qualities and how these influence the crucible properties, pulling process and ingot quality. This work has been performed in close collaboration between research partners and user partners in the center. Philip Weiser (UiO) presented the groundbreaking method developed in the center to measure hydrogen impurities in thin silicon wafers. This method are of interest for the user partners in the center and future collaboration are already initiated. Formation of dislocation clusters in multicrystalline silicon is always a challenge. Gaute Stokkan (SINTEF) presented exciting movies of how dislocations forms and moves in in-situ measurements performed during directional solidification of silicon. This fundamental work will be important in the future to control and suppress the formation of dislocation. The progress in the development of a method for producing kerffree silicon wafers with electron beam deposition at high temperature was presented by Marit Stange (SINTEF). This method is promising and have the potential for producing silicon wafers with no wafer sawing loss.

Session 3 – High efficiency silicon-based solar cells and modules

Using two solar cells in tandem can drastically increase the efficiency of solar cells. Martin Nyborg presented some of the opportunities and challenges related to tandem solar cells, where his work on doped Cu2O was set in an international context. Another path to high efficient solar cells is using photon conversion. By doing so, it is possible to split one high-energy UV photon into two visible light photons, doubling possible uptake of UV light. Vegard Rønning showed how to use lanthanides, which has very narrow bands that is unaffected by their neighbouring atoms, to split the UV light.

Many considerations must be made when integrating solar cells into the façades of buildings. For instance, how visible the solar cells are from the street, in what context the building is placed with regard to neighbouring buildings, and what type of building (i.e. church or storage facility). Some require a more sensitive approach than others. Changying Xiang presented his work on building a framework for evaluating solar cells from an architectural context. For integrating solar cells into façades in a harmonial manner, a larger variety of solar cells than the black module may be required. Coloured solar cells can better fit in with the neighbourhood palette, and pixelated facades is a way to include high efficiency solar cells where the average lightness of the building can still be high, providing lighter, electricity-producing neigbourhoods. Tore Kolås presented his work investigating pixelated buildings, coloured, transparent and opaque solar cells and their effect of PV efficiency.

Session 4 – End use and impact

In this session, four different topics were covered from the PhDs and Postdocs in the project. Postdoc Dimitra Chasanidou from the TIK center at UIO presented the work on Sustainability transitions and solar PV, where a literature survey has now been completed in order to understand how solar energy has contributes to the transition towards a more sustainable society. PhD student Marija Vukovic, from NMBU, presented the results on here work so far on advanced fault analysis of solar modules during daytime, using newly developed characterization techniques. PhD student Eivind Bekken Sveen, from UiO/IFE showed his results on method development used for assessing degradation rates, particularly in the Nordic region. PhD student Basant Raj Paudyal , from UiA, showed how the weather effects the colors in the incoming light, and how this may affect the performance of a PV system. He also showed how these results are being measured at their testing facility at UiA in Grimstad.