In this case no harm would be done to USA national security since I haven't worked in the area of my PhD research since 1972. On the other hand it might enhance USA national security for me to answer your questions since my answers would be worthless and misleading, thereby wasting your time, thereby advancing USA national security.
At the time I was doing my PhD research project (1968-1971), we were peripherally interested in solar power cells. Our experimental technique employed an electrolyte to make one contact to the semiconductor. It was thought that this technique might make the fabrication of photovoltaic cells cheaper by eliminating the need to deposit one of the contacts (the electrolyte flooding the surface provided that instead). Unfortunately the lifetime of such contacts was never long enough for a practical solar cell as "chemistry" would continue at the surface causing the buildup of insulating oxides. One could keep the surface clean by flowing fresh electrolyte over the surface but that would then involve an expensive fluid pumping and reclaim system, destroying the economic advantage of using an electrolyte in the first place.
Solar energy conversion is obviously a very important technology for decades to come. The problem for a young person is that, economically, it competes with fossil fuel solutions whose prices are highly manipulated by the producers. That is, just when the price of oil seems high enough to make a particular solar converter economical, the Saudi's can pump more barrels and drop the price, sending the solar investors scurrying for cover. The solar industry is thus plagued by boom and bust cycles that wreak havoc on the careers of the scientists and engineers involved.
