Illuminating Electron Microscopy of Photocatalysts

Photocatalysts are of fundamental interest for sustainable energy research [1]. By means of transmission electron microscopy (TEM) it is possible to obtain deep insight in the structure, composition and reactivity of photocatalysts for their further optimization [2]. We have constructed a novel specimen holder capable of shining light onto samples inside the TEM. The holder contains a laser diode and an optical system that guides light onto a sample with maximum power transmission. The source can be changed and tuned, in principle spanning the whole visible and UV spectrum. It is possible to use the device inside an environmental TEM (ETEM) in order to allow specimens to be exposed to controlled gas atmospheres during illumination. The holder is presently being used to study a variety of photoreactive materials and structures, including photocatalysts, photonic devices and solar cells. Here, we present preliminary results from Cu2O nanocubes, which show the effect of photodegradation under visible light exposure.