Templated Non-Oxide Sol-Gel Preparation of Well-Ordered Macroporous (inverse opal) Ta3N5 Films

Reactions Of Ta(NMeDs and riTropylamine, are shown to be an effeCtive. system for Sol-gel pakessing of Ta(3)Ns. Ordered macroporons films of Ta3Ns on silica 'into close,packed sacrificial templates of cross-linked SOO nrn Substiites have been prepared by infiltratiOn of suCh a sol polystyrene spheres followed by pyrolysis under ammonia to : remove the template and crystallize the Ta3N5. Templates with long-range order were produced by controlled humidity evaporation. Pyrolysis of a sol-infiltrated template at 600 C removes the polystyrene but does not crystallize Ta3N5, and X, ray diffraction shows nanocrystalline TaN plus amorphous material. Heating at 700 degrees C crystallizes Ta3N5 while retaining a high, degree of pore ordering, whereas at 800 C porous films with a complete loss of order are obtained.