High-Quality Green-Emitting Nanodiamonds Fabricated by HPHT Sintering of Polycrystalline Shockwave Diamonds

Abstract

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.

X-ray Excited Optical Luminescence of Eu in Diamond Crystals Synthesized at High Pressure High Temperature

“…To produce Eu-doped diamonds, we applied the HPHT method optimized in the synthesis of microdiamond powders from different carbon precursors such as detonation nanodiamond [ 19 ], shock-wave polycrystalline diamonds [ 20 ], and carbon black [ 21 ] together with pentaerythritol or ethanol as the hydrocarbon sources.…”

Diamond—the ultimate material for exploring physics of spin-defects for quantum technologies and diamondtronics

“…Further, diamond crystals grown using HPHT technique generally possess high surface roughness, and the post-polishing process is time consuming and expensive. Despite these drawbacks, HPHT diamond has been extensively used for optical as well as spin property studies [40][41][42].…”

A Review of Binderless Polycrystalline Diamonds: Focus on the High-Pressure–High-Temperature Sintering Process

“…Another lab from St. Petersburg, Russia, tried to directly sinter diamond compact from diamonds powders but using nano-diamonds powders of ~25 nm from detonation synthesis, i.e., with TNT/RDX ( Section 5.4 ) as starting materials [ 137 ]. The main goal focused on nitrogen-vacancy-nitrogen-center diamonds for biomedical applications.…”

“…References: ( a ) [ 5 ], Irifune et al, 2003; [ 56 ], Bundy, 1963; [ 102 ], Irifune et al, 2014; [ 110 ], Naka et al, 1976; [ 122 ], Sumiya et al, 2004; [ 123 ], Sumiya & Irifune, 2007; [ 124 ], Sumiya & Irifune, 2008; [ 125 ], Le Guillou et al, 2007; [ 126 ], Isobe et al, 2010; [ 127 ], Xu et al, 2013; [ 128 ], Sumiya, 2012; [ 129 ], Sumiya, 2017; [ 130 ], Sumiya& Harano, 2016; [ 131 ], Couvy et al, 2011; [ 132 ], Chang et al, 2014; [ 133 ], Sumiya et al, 2009. (b) [ 134 ], Lu et al, 2017; [ 135 ], Liu et al, 2018; [ 136 ], Li et al, 2020; [ 137 ], Osipov et al, 2020; [ 138 , 139 ], Dubrovinskaia et al, 2005a,b; [ 140 ], Irifune et al, 2020; [ 141 ], Merlen et al, 2009; [ 142 ], Solopova et al, 2015; [ 143 ], Dubrovinsky et al, 2012. (c) [ 144 ], Davydov et al, 2004; [ 145 ], Kawamura et al, 2020; [ 146 ], Park et al, 2020.…”