An Ultra-Broadband Near-Infrared Cr³⁺-Activated Gallogermanate Mg₃Ga₂GeO₈ Phosphor as Light Sources for Food Analysis

Abstract

A detailed nondestructive analytical method for quantitative food analysis was established by using a selffabricated NIR-LED light source combined with Mg 3 Ga 2 GeO 8 (MGGO) phosphor and a blue LED chip in one package, which can be integrated into smartphones. The phosphor of MGGO:Cr 3+ exhibits ultra-broadband NIR emission in the range of 650−1200 nm, which matches well with the overtones of molecular vibrations (e.g., O−H, C−H, and N−H) presented in food composition. The detailed crystal structure of MGGO was investigated by powder XRD Rietveld refinements, HRTEM images, and the corresponding SAED. Luminescence properties based on different Cr 3+ ions positions were investigated according to Gaussian peak fitting. Owing to the NIR response to organic elements, the working curves between absorbance and water content as well as sugar degree of pears and bananas were plotted. Then the reliability and veracity of the nondestructive analytical method were evaluated (R 2 = 0.9988). All the results suggest that the ultra-broadband NIR emission of MGGO:Cr 3+ phosphor has potential application as light sources integrated into smartphones for nondestructive food analysis.

Thermally Stable CaLu2Mg2Si3O12:Cr3+ Phosphors for NIR LEDs

“…Comprehending kinds of reported NIR phosphors, Cr 3+ is believed to be one kind of the best activators due to its tuneable broadband and efficient NIR emission. [2,14,15,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Correspondingly, the radiant power of NIR light was improved from 7-18.2 mW [25,33] to 43.1-81 mW [14,21,30,31] for the NIR pcLEDs driven at 350 mA. To achieve a high NIR radiation, the key is how to simultaneously possess a high efficiency and good thermal stability in NIR phosphors.…”

Enticing applications of near‐infrared phosphors: Review and future perspectives

“…[ 25 ] When an investigated sample is irradiated with NIR light, a characteristic spectrum can generally be observed as a result of the specific absorptions and reflections present in most chemical compounds that can be seen in the daily products we use or consume. [ 7,8 ] It must be noted that the initial radiation of the phosphor must be overlapping with the characteristic absorptions and reflections of the investigated samples. Thus, allowing the user to monitor the contents of the investigated sample.…”

“…Furthermore, the emission band in Figure 6c is consistent with the second O–H overtones in water ranging from 970 to 980 nm; the second and third O–H overtones in soluble sugar are found at 920 and 720 nm, respectively; and Figure 6d is in accordance with the fourth C–H overtones in soluble sugar at 750 nm. [ 8,9,28,29 ] The NIR‐LED is demonstrated to be a feasible device as a nondestructive analytical tool for demonstrating food quality control. However, the results are preliminary; thus, further calibration and testing are necessary for the device to be commercially viable.…”

“…[ 5 ] NIR‐based LED technology has recently gained a significant amount of interest in the scientific and industrial communities. These LEDs have been incorporated in various devices, most of which are applied in the spectroscopic, [ 6–10 ] biological, [ 11–14 ] and agricultural fields. [ 15–17 ]…”

The hydrothermally synthesis of K3AlF6:Cr3+ NIR phosphor and its performance optimization based on phase control

“…[15][16][17][18] One strategy is to employ transition-mental ions, Cr 3+ for instance. [19][20][21] The main hosts for Cr 3+ -doped NIR phosphor are germanate, [22][23][24][25][26][27] silicate, [28][29][30][31][32] phosphate, [33][34][35] and borate. [36][37][38][39] The synthesis of these phosphors requires calcination at a temperature of 800-1600°C, which results in high production costs.…”