The present invention provides a fluorescent diamond containing an MV center emitting fluorescence at a concentration of 1×10.sup.14/cm.sup.3 or higher, where M represents a metal or metalloid, and V represents a vacancy.

The present invention provides a fluorescent diamond containing an MV center emitting fluorescence at a concentration of 1×10.sup.14/cm.sup.3 or higher, where M represents a metal or metalloid, and V represents a vacancy.

A calibration target for calibrating an optoelectronic device for analyzing biomolecules by detecting fluorescence signals from a sample includes a substrate and a solid fluorescent layer that is disposed on the substrate and capable of being excited by laser light. The fluorescent layer has an optically inactive matrix having embedded therein a carbon-based component that is excitable to light emission.

A method of controlled production of luminescent diamond particles exhibiting luminescence in selected specific spectral ranges is provided. The method comprises taking diamond particles containing dopant atoms in the diamond core, irradiating the particles with high energy radiation, and annealing the irradiated diamond particles at a target temperature in the temperature range of about 1400° C.-2200° C. to form luminescent diamond particles where the specific spectral range of luminescence is controlled by the target temperature of the annealing process, the irradiation dose, and the type of dopant atoms. Duration of the annealing and the temperature ramp up and ramp down times should be short enough to minimize or prevent significant graphitization of the particles. Duration of the temperature ramp up time should be short enough to minimize formation of color centers that might form at temperatures below the target temperature.

A method of controlled production of luminescent diamond particles exhibiting luminescence in selected specific spectral ranges is provided. The method comprises taking diamond particles containing dopant atoms in the diamond core, irradiating the particles with high energy radiation, and annealing the irradiated diamond particles at a target temperature in the temperature range of about 1400° C.-2200° C. to form luminescent diamond particles where the specific spectral range of luminescence is controlled by the target temperature of the annealing process, the irradiation dose, and the type of dopant atoms. Duration of the annealing and the temperature ramp up and ramp down times should be short enough to minimize or prevent significant graphitization of the particles. Duration of the temperature ramp up time should be short enough to minimize formation of color centers that might form at temperatures below the target temperature.

A method of producing a fluorescent nanodiamond exhibiting a zero phonon line (ZPL) for NV.sup.0 and/or NV.sup.− on its the fluorescence emission wavelength spectrum. The method includes a detonation step of exploding at least one type of explosive in an airtight container to obtain a nanodiamond raw material, a first annealing step of annealing, at a temperature from 1000° C. to 1600° C., the nanodiamond raw material or a nanodiamond which is obtained by removing sp2 carbon through strong acid treatment, ozone treatment, or gas-phase oxidation of the nanodiamond raw material, a vacancy forming step of creating vacancies on the nanodiamond by irradiating the nanodiamond with an ion beam or an electron beam after the first annealing step, and a second annealing step of annealing, at a temperature from 600° C. to 900° C., the nanodiamond containing vacancies to form Nitrogen-Vacancy (NV) centers.

A method of producing a fluorescent nanodiamond exhibiting a zero phonon line (ZPL) for NV.sup.0 and/or NV.sup.− on its the fluorescence emission wavelength spectrum. The method includes a detonation step of exploding at least one type of explosive in an airtight container to obtain a nanodiamond raw material, a first annealing step of annealing, at a temperature from 1000° C. to 1600° C., the nanodiamond raw material or a nanodiamond which is obtained by removing sp2 carbon through strong acid treatment, ozone treatment, or gas-phase oxidation of the nanodiamond raw material, a vacancy forming step of creating vacancies on the nanodiamond by irradiating the nanodiamond with an ion beam or an electron beam after the first annealing step, and a second annealing step of annealing, at a temperature from 600° C. to 900° C., the nanodiamond containing vacancies to form Nitrogen-Vacancy (NV) centers.

The present invention relates to a fluorescent nanodiamond preparing method including a first operation of preparing nanodiamonds having an average particle diameter of 10 nm or less, a second operation of implanting plasma ions into the nanodiamonds, a third operation of heat-treating the nanodiamonds implanted with the plasma ions under a vacuum or inert gas atmosphere, a fourth operation of oxygen treatment of the heat-treated nanodiamonds under a gas atmosphere including oxygen to oxidize the surfaces of the nanodiamonds, a fifth operation of acid-treating the oxygen-treated nanodiamonds, a sixth operation of centrifuging and cleaning the acid-treated nanodiamonds, and a seventh operation of drying the cleaned nanodiamonds, wherein, in the second operation, the plasma ions are implanted at an incident ion dose of 10.sup.13 ions/cm.sup.2 or more and 10.sup.20 ions/cm.sup.2 or less.

The present invention relates to a fluorescent nanodiamond preparing method including a first operation of preparing nanodiamonds having an average particle diameter of 10 nm or less, a second operation of implanting plasma ions into the nanodiamonds, a third operation of heat-treating the nanodiamonds implanted with the plasma ions under a vacuum or inert gas atmosphere, a fourth operation of oxygen treatment of the heat-treated nanodiamonds under a gas atmosphere including oxygen to oxidize the surfaces of the nanodiamonds, a fifth operation of acid-treating the oxygen-treated nanodiamonds, a sixth operation of centrifuging and cleaning the acid-treated nanodiamonds, and a seventh operation of drying the cleaned nanodiamonds, wherein, in the second operation, the plasma ions are implanted at an incident ion dose of 10.sup.13 ions/cm.sup.2 or more and 10.sup.20 ions/cm.sup.2 or less.

The present invention is to provide a heteroatom-doped nanodiamond, the heteroatom-doped nanodiamond being doped with at least one heteroatom, the heteroatom-doped nanodiamond satisfying criteria (i) and/or (ii) below: (i) a BET specific surface area being from 20 to 900 m.sup.2/g, and (ii) an average size of primary particles being from 2 to 70 nm.