Guizhou University

In this study, a portable photoelectrochemical diagnostic platform based on CuCo₂O₄@ZnIn₂S₄ nanocomposites and a smartphone was developed to detect dopamine (DA). CuCo₂O₄@ZnIn₂S₄ heterojunction was prepared by a simple one-pot method, and it was found that CuCo₂O₄@ZnIn₂S₄ showed significant photoelectrochemical (PEC) activity. DA acts as an electron donor and interacts with the composites. The holes in the composites oxidize DA to produce dopaquinone, reducing the electron-hole recombination rate and increasing the photocurrent signals. These signals can be immediately read using a portable smartphone. The results of this study confirmed that the increase in the photocurrent of the sensor was linked to the interaction between DA and the composites. Under optimized conditions, the linear range was 0.01-2000 μM, and the limit of detection (LOD) was 0.08 μM (S/N = 3). The sensor performs well on human serum samples and demonstrates high long-term stability. Therefore, convenient photoelectrochemical analysis of serum is achievable using a user-friendly, portable smartphone detection device.

The supramolecular fluorescent probe exhibited promising application in the field of detection and analysis, but developing supramolecular fluorescent probes with long wavelength emission and enhancement functions for the detection of phenylethylamines is a challenge. In this work, the guest molecule SPn with a D-π-A structure was designed and synthesized, and supramolecular fluorescent probe (SPn/Q[8]) with long wavelength emission was constructed by the host-guest interaction with cucurbit[8]uril (Q[8]). This probe detects phenethylamines based on an indicator displacement assay, which is a process characterized by a fast effect rate (within 6.24 s), high selectivity, and low detection limit. In addition, a smartphone-based quantitative detection system was developed for trace detection of phenethylamine, with a detection limit of 2.35 μM. This research not only developed a new approach for supramolecular fluorescent probes, but also provided a useful tool for the on-site detection of phenylethylamine.

Europium (Eu³⁺)-doped phosphors, widely used in lighting and displays due to orange/red emissions from ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ transitions, face inherent limitations such as low efficiency and weak ⁵D₀ → ⁷F₄ transitions, hindering far-red emission. This study presents SrGa₄O₇: 0.3Eu³⁺ (SGO: 0.3Eu³⁺) deep-red phosphors that overcome these constraints by dominantly utilizing the ⁵D₀ → ⁷F₄ transition (701 nm) under near-UV excitation. The optimized SGO: 0.3Eu³⁺ exhibits exceptional thermal stability, retaining 76 % (393 nm) and 79 % (464 nm) of its room-temperature (300K) emission intensity at 425 K. This phosphor delivers an impressive Quantum yield (QY) of 31.95 % when excited at 393 nm. When integrated with standard blue and green phosphors, the resulting white light-emitting diode (WLED) produces a spectrum ideally suited for plant cultivation. The WLED achieves precise color metrics-with chromaticity coordinates at (0.3669, 0.3848), an excellent color rendering index (CRI) of 91.9, and Correlated Color Temperature (CCT) of 4432 K. Additionally, the deep-red LED prototype, featuring coordinates of (0.6294, 0.3581) and an outstanding 96.4 % color purity, proves highly effective for stimulating plant growth. These results highlight SGO: 0.3Eu³⁺ as an outstanding red-emitting candidate for plant lighting, offering efficient and high-quality solutions for modern agricultural facilities. Its superior optical properties also suggest potential applications in fingerprint detection, anti-counterfeiting ink and related fields.