For a science fair project, I am going to test  some various organic dye sources and see how that affects the efficiency of dye sensitized solar cells. I was curious if I needed a specific type or titanium dioxide or if normal TiO2 would work if I friended it in a mortar and pestle. Any information would be appericiated, thanks.

Assuming you’re talking about anatase structure, it works better than rutile but rutile should still work. I’m not sure if the results will be proportional though.