Liquid-phase Synthesis of Crystalline Metal Nitride Nanoparticles with Semiconductor-type Properties (NanoNitrid)

制备粒度均匀、结晶度高、纯度高的金属氮化物纳米颗粒仍是一个挑战。这是由于氨解反应中氨难以完全去质子化和氮化反应中氮的惰性所致。因此，通常使用高温（50 ~ 500℃）和在许多情况下含氧的起始材料（金属氧化物、金属氢氧化物），这对于均匀、无团块和无氧的金属氮化纳米颗粒来说自然是适得其反的。另一方面，金属氮化纳米颗粒的材料特性非常有趣，包括量子约束效应、催化作用、气体吸附和半导体的电子或光学特性。该项目的目的是从最初的目标微乳液与液氨（第一个资助期）转移到一个新的，更有利的合成策略。因此，金属酰胺纳米颗粒首先在液氨中成核，随后在吡啶（或类似物质）或离子液体中通过一锅方法转化为结晶金属氮化纳米颗粒。目标化合物是具有半导体性质的二元和三元金属氮化物纳米颗粒（即Sc2N3， Y2N3, Mn3N2, Zn3N2； ZnMN2具有M: Si， Ge, Sn, Ti, Zr，或MWN3具有M: Sc， Y, La）。此外，我们将开发选定化合物的尺寸和形状控制的概念，这在很大程度上是纳米级金属氮化物所未知的。为了表征所制备的金属氮化物的尺寸、结构和相纯度（特别是不含金属氧化物/碳化物），现代电子显微镜和光谱学自然是主要的分析方法。

The synthesis of metal nitride nanoparticles with uniform particle size, high crystallinity and purity remains a challenge. This is due to the difficulty of complete deprotonation of ammonia in ammonolysis reactions and the inertness of nitrogen in nitridation reactions. Therefore, high temperatures (>500 °C) and in many cases oxygen-containing starting materials (metal oxides, metal hydroxides) are usually used, which is naturally counterproductive with respect to uniform, agglomerate-free and oxygen-free metal nitride nanoparticles. On the other hand, metal nitride nanoparticles are highly interesting with respect to their material properties, including quantum-confinement effects, catalysis, gas sorption and electronic or optical properties of semiconductors.The aim of this project is to move away from the initially targeted microemulsions with liquid ammonia (1st funding period) to a new, far more advantageous synthesis strategies. Accordingly, metal amide nanoparticles are first nucleated in liquid ammonia and subsequently converted into crystalline metal nitride nanoparticles in a one-pot approach in pyridine (or similar) or in ionic liquids. Target compounds are binary and ternary metal nitride nanoparticles with semiconducting properties (i.e., Sc2N3, Y2N3, Mn3N2, Zn3N2; ZnMN2 with M: Si, Ge, Sn, Ti, Zr, or MWN3 with M: Sc, Y, La). Furthermore, we will develop concepts for size and shape control of selected compounds, which are yet largely unknown for nanoscale metal nitrides. For the characterization of size, structure and phase purity of the as-prepared metal nitrides (especially absence of metal oxides/carbides), modern electron microscopy and spectroscopy are naturally the central analytical methods.