Energetic materials is a rather innocuous sounding expression for far-from-innocuous materials, they are explosives (I think at least some fuels are also classified as energetic materials). The idea being that energetic materials are materials that can yield large amounts of energy, and explosives can certainly do that, and very rapidly too.
Many energetic materials are crystals, so as I work on crystallisation I occasionally bump into scientists who work on them at conferences. I also come across papers on explosives, for example I have just read a nice one by Kim et al, from a university in Korea. They are studying the crystallisation of the explosive RDX, and show some good quantitative data for how this explosive crystallises out from solution.
Together with Joe Keddie, another academic at Surrey, I have a PhD student starting the week after next, who will also be studying crystallisation. I don’t think we’ll start him off on RDX. Entertaining as the expression on the safety officer’s face might be when confronted with a protocol for experiments on RDX, there are easier, safer substances to crystallise.