Osipov Vladimir Yu, Shakhov Fedor M, Bogdanov Kirill V, Takai Kazuyuki, Hayashi Takuya, Treussart François, Baldycheva Anna, Hogan Benjamin T, Jentgens Christian
Ioffe Institute, Polytechnicheskaya 26, St. Petersburg, Russia, 194021.
ITMO University, Kronverksky 47, St. Petersburg, Russia, 197101.
Nanoscale Res Lett. 2020 Nov 9;15(1):209. doi: 10.1186/s11671-020-03433-7.
We demonstrate a high-pressure, high-temperature sintering technique to form nitrogen-vacancy-nitrogen centres in nanodiamonds. Polycrystalline diamond nanoparticle precursors, with mean size of 25 nm, are produced by the shock wave from an explosion. These nanoparticles are sintered in the presence of ethanol, at a pressure of 7 GPa and temperature of 1300 °C, to produce substantially larger (3-4 times) diamond crystallites. The recorded spectral properties demonstrate the improved crystalline quality. The types of defects present are also observed to change; the characteristic spectral features of nitrogen-vacancy and silicon-vacancy centres present for the precursor material disappear. Two new characteristic features appear: (1) paramagnetic substitutional nitrogen (P1 centres with spin ½) with an electron paramagnetic resonance characteristic triplet hyperfine structure due to the I = 1 magnetic moment of the nitrogen nuclear spin and (2) the green spectral photoluminescence signature of the nitrogen-vacancy-nitrogen centres. This production method is a strong alternative to conventional high-energy particle beam irradiation. It can be used to easily produce purely green fluorescing nanodiamonds with advantageous properties for optical biolabelling applications.
我们展示了一种高压高温烧结技术，用于在纳米金刚石中形成氮-空位-氮中心。平均尺寸为25纳米的多晶金刚石纳米颗粒前驱体由爆炸产生的冲击波制备而成。这些纳米颗粒在乙醇存在的情况下，于7吉帕的压力和1300℃的温度下进行烧结，以生成尺寸大得多（3至4倍）的金刚石微晶。记录的光谱特性表明晶体质量得到了改善。还观察到存在的缺陷类型发生了变化；前驱体材料中存在的氮-空位和硅-空位中心的特征光谱特征消失了。出现了两个新的特征：（1）具有顺磁性替代氮（自旋为½的P1中心），由于氮核自旋的I = 1磁矩而具有电子顺磁共振特征三重态超精细结构；（2）氮-空位-氮中心的绿色光谱光致发光特征。这种生产方法是传统高能粒子束辐照的有力替代方法。它可用于轻松制备具有光学生物标记应用优势特性的纯绿色荧光纳米金刚石。
