Fluorescent nanodiamond is a new nanomaterial that possesses several useful properties, including good biocompatibility1, excellent photostability1,2 and facile surface functionalizability2,3. Moreover, when excited by a laser, defect centres within the nanodiamond emit photons that are capable of penetrating tissue, making them well suited for biological imaging applications1,2,4. Here, we show that bright fluorescent nanodiamonds can be produced in large quantities by irradiating synthetic diamond nanocrystallites with helium ions. The fluorescence is sufficiently bright and stable to allow three-dimensional tracking of a single particle within the cell by means of either one- or two-photon-excited fluorescence microscopy. The excellent photophysical characteristics are maintained for particles as small as 25 nm, suggesting that fluorescent nanodiamond is an ideal probe for long-term tracking and imaging in vivo, with good temporal and spatial resolution.

Mass production and dynamic imaging of fluorescent nanodiamonds

Recent advances in dual-emission ratiometric fluorescence probes for chemo/biosensing and bioimaging of biomarkers

Ratiometric fluorescence sensing of metal-organic frameworks: Tactics and perspectives

Hetero-nanostructured metal oxide-based hybrid photocatalysts for enhanced photoelectrochemical water splitting – A review

Finding efficient cyan phosphors with broadband absorption in the near-ultraviolet range (380–420 nm) and bright emission around 490 nm are highly important to make up for the so-called cyan gap (480–520 nm) in traditional tricolor (blue, green and red) phosphor-converted white light-emitting diodes (LEDs). Herein, we reported a new garnet phosphor, namely Ca2LuZr2(AlO4)3:Ce3+ (CLZA:Ce3+), with a cyan-emitting band, which enabled to fill the cyan gap and realize high color rendering white LEDs. The composition-optimized CLZA:1% Ce3+ phosphors showed an intense broad excitation band in the 370–475 nm wavelength range peaked at 408 nm and a broad asymmetric emission band at around 483 nm in the wavelength range of 414–650 nm. Importantly, the cyan-emitting CLZA:1% Ce3+ phosphors possessed a luminescence efficiency of 58%. Notably, the CLZA:1% Ce3+ cyan phosphors allowed to fill the cyan gap between the blue and green emission bands in white LEDs, and the value of color rendering index could be enhanced from 82.3 to 89.2. This study provides new insights into designing and developing suitable efficient phosphors for high-color-quality solid-state white lighting.

https://pubs.rsc.org/en/content/articlepdf/2020/tc/c9tc04952e

A broadband cyan-emitting Ca 2 LuZr 2 (AlO 4 ) 3 :Ce 3+ garnet phosphor for near-ultraviolet-pumped warm-white light-emitting diodes with an improved color rendering index

A hybrid nanostructure based on ZnO quantum dots (QDs) has been fabricated for ratiometric detection of Bacillus anthracis spores, where yellow-emitting ZnO QDs are employed as the internal reference and europium ions (Eu3+) are chelated on the surface of the ZnO QDs as the signal report unit. The Eu3+ exhibits enhanced red luminescence upon bonding with calcium dipicolinate (CaDPA), an important biomarker of Bacillus anthracis spores, while the fluorescence of the ZnO QDs will not be altered. Accordingly, increased CaDPA levels can lead to variation of the two fluorescence intensity ratios of the ZnO/Eu hybrid nanostructure. The time-dependent fluorescence response reveals that the reaction can be completed within 8 s, thus enabling the rapid detection of Bacillus anthracis spores. The detection limit for CaDPA is 3 nM, which is six orders of magnitude lower than an infectious dosage of Bacillus anthracis spores for human beings (60 μM). In addition, the sensor shows a remarkable selectivity for CaDPA over other aromatic ligands, amino acids and common cellular ions. The fast response speed as well as good sensitivity and selectivity means the ZnO/Eu nanostructure has great potential applications in clinical analysis.

Europium-decorated ZnO quantum dots as a fluorescent sensor for the detection of an anthrax biomarker

Nanodiamonds conjugated upconversion nanoparticles for bio-imaging and drug delivery

Room temperature phosphorescence (RTP) materials show potential applications in information security and optoelectronic devices, but it is still a challenge to achieve RTP in organic materials under water ambient due to the unstable property of triplet states. Herein, water-induced RTP has been demonstrated in the organic microrod (OMR). Noting that the RTP intensity of the as-prepared OMR is greatly enhanced when water is introduced, and the reason for the enhancement can be attributed to the formation of hydrogen-bonded networks inside the OMR. The hydrogen-bonded networks can confine the molecular motion effectively, leading to the stability of triplet states; thus the lifetime of the OMR can reach 1.64 s after introducing water. By virtue of the long lifetime of the OMR in the presence of water, multilevel data encryption based on the OMR has been demonstrated.

Water-induced ultralong room temperature phosphorescence by constructing hydrogen-bonded networks

https://iopscience.iop.org/article/10.1088/1361-6463/abae36/pdf

Solar-blind photodetectors based on MXenes–β-Ga2O3 Schottky junctions

Limited light absorption and low charge separation rate are the main obstacles for graphitic carbon nitride (g-C3N4)-based photocatalyst. Here, onion-liked carbon (OLC), a carbon nanostructure with multilayer graphitic shells, was embedded into the g-C3N4 matrix to enhance the photocatalytic performance. Due to its high degree of sp2 hybridization and good electrical conductivity, the OLC can broaden visible light adsorption, narrow the band gap of g-C3N4, and serve as electron acceptor to promote the separation of photo-generated carrier. Thus, the g-C3N4/OLC composites show an increased hydrogen evolution rate of 3086 μmol g−1 h−1, 4.44 times higher than pure g-C3N4. Furthermore, the H2 evolution rate is highly related to the sp2/sp3 ratio of OLC. In addition, efficient photocatalytic degradation of RhB was also achieved (0.1171 min−1). The photocatalytic mechanism was then elucidated through a series of spectrochemical and photochemical test. This work demonstrates the significant applicability of OLC in designing carbon-based photocatalyst with highly-efficient photocatalytic activity towards future solar energy conversion and pollutants degeneration. 

Qi Zhao

Papers

Europium-decorated ZnO quantum dots as a fluorescent sensor for the detection of an anthrax biomarker

Nanodiamonds conjugated upconversion nanoparticles for bio-imaging and drug delivery

Water-induced ultralong room temperature phosphorescence by constructing hydrogen-bonded networks

Solar-blind photodetectors based on MXenes–β-Ga2O3 Schottky junctions

Onion-liked carbon-embedded graphitic carbon nitride for enhanced photocatalytic hydrogen evolution and dye degradation