Synthesis of Porous Connected Cryoaerogel Networks from Cadmium Chalcogenide Nanoplatelet Stacks

Cadmium chalcogenide nanoplatelets (NPLs) are not only known due to their unique optical properties but also because of their ability to self-assemble into stacks with new collective properties. Only recently, a stacking process in an aqueous medium has been demonstrated, which opens up possible applications and methods such as gelation. Nanoparticle-based aerogels gain a lot of attention due to their high relative surface areas and porosity and thus, high potential for catalytic applications. Herein, the positive properties of aerogels to the NPL-stack system by cryoaerogelation of destabilized NPL dispersions are introduced. After the addition of an antisolvent to initiate the stacking, the dispersion is flash-frozen with liquid nitrogen and freeze-dried. By this method, porous cryoaerogel networks result in high surface areas and retained stacking of the NPLs. The formed stack-gels are investigated by electron microscopy and physisorption measurements. Optical and photoelectrochemical measurements verify the charge carrier transport within the stack-gel network.