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Spintronic states-associated photoluminescence (PL) is of interest and essential for electronic spin-manipulated information storage and communications. Manganese ions (Mn2+)-doped semiconductor quantum dots (QDs) exhibit a unique PL that comes from the spin-forbidden 4T1–6A1 d–d transition of Mn2+, which is a promising candidate for a spin-manipulated light source. However, the interplay of PL quantum yield (PL QY) and the magnetic states of Mn2+ dopants is still vague. In this work, we systematically investigate the spectroscopic properties of Mn2+-doped ZnSe/ZnS core–shell QDs. By increasing the doping concentration, the PL QY of the Mn2+ dopant is increased to a maximum of 43.2% (2% Mn2+-doped QDs) before decreasing for higher-doped QDs (10% Mn2+-doped QDs). We further found that the high doping in the QDs induces the magnetic coupling of Mn2+ ions, which leads to a larger PL intensity and line-width variation as a function of the temperature from 300 to 80 K. The abnormal PL line-width derivation of high-doped QDs occurs around 150 and 240 K, where would be the Neel temperature of MnS and MnSe, respectively, which allows transition between para-magnetism and anti-ferromagnetism. Our findings of doping-concentration-dependent PL QY and magnetism transition-related PL variation in this work offer a vision for the spintronic states-associated PL of the Mn2+ dopant in the QD host. [ABSTRACT FROM AUTHOR]

Efficient and reliable technologies for the on-site detection of illicit drugs are important in drug-facilitated crime investigations. However, the development of such technologies is challenging. Based on the synthetic optimization, introducing a boron ester functional group to the two furanic indicators endows the stimulus-responsive properties synergistically. The ring-opening reaction of the indicators in the presence of amine-containing illicit drugs generated well-known donor-acceptor Stenhouse adducts, accompanied by strong color changes. A small-size and lightweight laminated sensor was integrated based on the outstanding ratiometric variations of the two active furanic indicators. A prototype platform was fabricated equipped with a circuit control, a mini pump, and a signal processing system. A user-friendly detection and efficient screening of amine-containing illicit drugs, including phenethylamines, amphetamines, cathinones, and tryptamines in the liquid states were conducted. The ratiometric response of the sensor was linear in the concentration range of 2.1-10.6 μg·mL -1 for methamphetamine·HCl and methcathinone ·HCl. The detection limits for the two illicit drugs at the sublevel (ng·mL -1 ) were found to be 8.4 and 9.0 ng·mL -1 , respectively. Double-blind field tests and different illicit drugs were evaluated with good screening capability. Successful trials showed the potential applications of the developed prototype platform for efficient and on-site analytical determination.