When investing in solar panels for an off-the-grid 24VDC electrical system, the lifetime of the different types of solar cells is a central consideration for max sustainability.
Through light induced degradation [LID] experiments involving light & dark heat exposure and annealing, there is proof that newer ribbon-type silicon produces the most cost effective & environmentally friendly solar cells. Elder Czochralski-method-based solar cells suffer from LID, while ribbon silicon cells exhibit no LID.
So, it would seem that silicon ribbon solar cells may be the best investment. I will update this post when I have evaluated pricing/performance/availability of such cells.