On the glow of cremated remains: long-lived green photo-luminescence of heat-treated human bones.

The long-lived green luminescence of human bone (that has been heated to 600 °C for a short duration) is attributed to a carbon quantum dot material (derived from collagen) encapsulated and protected by an inorganic matrix (derived from bone apatite) and is more intense in dense rigid and crystalline parts of (healthy) human bones. The strong collagen-apatite interaction results (upon decomposition) in a protective inorganic environment of the luminescent centers allowing long-lived triplet-based emission of a carbon (quantum) dot-like material at room temperature, as well as resilience against oxidation between 550 and 650 °C. The graphitic black phase (obtained upon heating around 400 °C) is a precursor to the luminescent carbon-based material, that is strongly interacting with the crystalline inorganic matrix. Human bone samples that have been heated to 600 °C were subjected to steady-state and time-resolved spectroscopy. Excitation-emission matrix (EEM) luminescence spectroscopy revealed a broad range of excitation and emission wavelengths, indicating a heterogeneous system with a broad density of emissive states. The effect of low temperature on the heat-treated bone was studied with Cryogenic Steady State Luminescence Spectroscopy. Cooling the bone to 80 K leads to a slight increase in total emission intensity as well as an intensity increase towards to red part of the spectrum, incompatible with a defect state model displaying luminescent charge recombination in the inorganic matrix. Time-resolved spectroscopy with an Optical Multichannel Analyzer (OMA) and Time Correlated Single Photon Counting (TCSPC) of these samples showed that the decay could be fitted with a multi-exponential decay model as well as with second-order decay kinetics. Confocal Microscopy revealed distinct (plywood type) structures in the bone and high intensity-fast decay areas as well as a spatially heterogeneous distribution of green and (fewer) red emissive species. The use of the ATTO 565 dye aided in bone-structure visualization by chemical adsorption. Conceptually our data interpretation corresponds to previous reports from the material science field on luminescent powders.

Schut E ，Breedijk RMP ，Hilbers MF ，Hink MA ，Krap T ，Aalders MCG ，Williams RM ... -  《-》

Phosphorescence of thermally altered human bone.

Krap T ，Busscher L ，Oostra RJ ，Aalders MCG ，Duijst W ... -  《-》

Luminescence of thermally altered human skeletal remains.

Krap T ，Nota K ，Wilk LS ，van de Goot FRW ，Ruijter JM ，Duijst W ，Oostra RJ ... -  《-》

Full-color Persistent Room-temperature Phosphorescence from Carbon Dot Composites Based on a Single Nonaromatic Carbon Source.

Herein, a series of carbon dot composites (CDC) with full-color and long-lived room-temperature phosphorescence (RTP) are prepared by a simple solid-phase one-step method from a single non-conjugated and non-aromatic carbon source. The RTP emission wavelength can be adjusted from 462 to 623 nm by changing the feeding ratio and reaction temperature. The luminescent lifetime and quantum yield of a green emissive CDC (AB-CDC-3) reach 1.1 s and 39%, respectively, because of the close interaction between carbon dots and inorganic matrix. Due to the existence of multiple luminescent centers, these CDC exhibit excitation wavelength-dependent RTP and a white emission when excited at a specific wavelength. A single-component afterglow luminescent diode based on AB-CDC-4 shows a high-quality white emission with CIE of (0.30, 0.33) and color-rendering index of 88. Based on the unique photophysical properties of the composites, they exhibit huge application potential in the field of multilevel anti-counterfeiting, fingerprint identification, and optoelectronic devices.

Wang X ，Wang S ，Huang Y ，Huang L ，Sun J ，Lin Z ... -  《-》

Thermal and electron stimulated luminescence of natural bones, commercial hydroxyapatite and collagen.

The luminescence (cathodoluminescence and thermoluminescence) properties of natural bones (Siberian mammoth and adult elephant), commercial hydroxyapatite and collagen were analyzed. Chemical analyses of the natural bones were determined using by Electron Probe Micro-Analysis (EMPA). Structural, molecular and thermal characteristics were determined by X-ray Diffraction (XRD), Raman spectroscopy and Differential Thermal and Thermogravimetric analysis (DTA-TG). Cathodoluminescence (CL) spectra of natural bones and collagen showed similar intense broad bands at 440 and 490 nm related to luminescence of the tetrahedral anion [Formula: see text] or structural defects. A weaker luminescence exhibited at 310 nm could be attributed to small amount of rare earth elements (REEs). Four luminescent bands at 378, 424, 468 and 576 nm were observed in the commercial hydroxyapatite (HAP). Both natural bones and collagen samples exhibited natural thermoluminescence (NTL) with well-defined glow curves whereas that the induced thermoluminescence (ITL) only appears in the samples of commercial hydroxyapatite and collagen. Additional explanations for the TL anomalous fading of apatite, as a crucial difficulty performing dosimetry and dating, are also considered.

Roman-Lopez J ，Correcher V ，Garcia-Guinea J ，Rivera T ，Lozano IB ... -  《-》