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The Ca2MgSi2O7:Eu2+ and Ca2MgSi2O7:Eu2+, Dy3+ long afterglow phosphors were synthesized under a weak reducing atmosphere by the traditional high temperature solid state reaction method. The synthesized phosphors were characterized by powder X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) techniques. The luminescence properties were investigated using thermoluminescence (TL), photoluminescence (PL), long afterglow, mechanoluminescence (ML), and ML spectra techniques. The crystal structure of sintered phosphors was an akermanite type structure, which belongs to the tetragonal crystallography. TL properties of these phosphors were investigated, and the results were also compared. Under the ultraviolet excitation, the emission spectra of both prepared phosphors were composed of a broad band peaking at 535 nm, belonging to the broad emission band. When the Ca2MgSi2O7:Eu2+ phosphor is co-doped with Dy3+, the PL, afterglow and ML intensity is strongly enhanced. The decay graph indicates that both the sintered phosphors contain fast decay and slow decay process. The ML intensities of Ca2MgSi2O7:Eu2+ and Ca2MgSi2O7:Eu2+, Dy3+ phosphors were proportionally increased with the increase of impact velocity, which suggests that this phosphor can be used as sensors to detect the stress of an object.

An excellent long afterglow SrCaMgSi2O7:Eu2+, Dy3+ phosphor was prepared by the high-temperature solid-state reaction method. The phase structure of prepared phosphor was an akermanite-type structure, which belongs to the tetragonal crystallography with space group $$ {\text{P}}\overline{{{\text{42}}}} _{{\text{1}}} {\text{m}} $$ . Chemical composition of the sintered SrCaMgSi2O7:Eu2+, Dy3+ phosphor was confirmed by EDX. Under ultraviolet excitation, the SrCaMgSi2O7:Eu2+, Dy3+ phosphor would emit bluish-green (cyan) light, belonging to the broad emission band ascribed to the 4f65d1 → 4f7 transition. Investigation of afterglow properties show that SrCaMgSi2O7:Eu2+, Dy3+ phosphor held a fast and slow decay process. The peak of ML intensity increases linearly with increasing impact velocity of the moving piston. The CIE chromaticity diagram and ML spectra show a similar spectrum as PL spectra, which indicated that ML is emitted from the same emitting center of Eu2+ ions. Thus the present investigation indicates that the piezoelectrically induced de-trapping model is responsible to produce ML in prepared SrCaMgSi2O7:Eu2+, Dy3+ phosphor.

A new simple and sensitive spectrophotometric method for some phenothiazine derivatives has been developed. The proposed method is based on the reaction of phenothiazine derivatives promethazine hydrochloride, chlorpromazine hydrochloride, triflupromazine hydrochloride, prochlorperazine, and trifluoperazine with potassium iodate followed by reaction of liberated iodine with leuco crystal violet (LCV) and measurement of the color of the oxidized LCV at 598 nm. The method showed a good linearity in the ranges 0.05–4.0, 0.02–2.0, 0.05–5.0, 0.1–8.0, and 0.05–2.0 µg mL−1 respectively. The optimum conditions and other analytical parameters were evaluated. The proposed methods have been applied successfully to the analysis of phenothiazine derivatives in pure form and in their dosage forms, and no interference was observed from common excipients present in pharmaceutical formulations.

A simple, sensitive, extractive spectrophotometric method for determination of α-methyldopa in both pure form and in pharmaceutical formulations is described. The method is based on the reaction of diazotized p-aminoacetophenone with α-methyldopa in basic medium to yield an orange-yellow-coloured product having an absorption maximum at 440 nm. The orange-coloured species was extracted in isopentanol. The coloured species obeyed Beer’s law in the range of 0.05–0.5 µg/mL. The molar absorptivity as obtained from Beer’s law data was found to be 0.3736 × 106 L mol−1 cm−1, while Sandell’s sensitivity was found to be 0.00064 µg cm−2. Common excipients did not interfere with the proposed method. The result obtained by the proposed method compares favorably with other reported methods. The proposed method offers the advantages of simplicity and higher sensitivity over the other existing methods.

The present paper reports synthesis and thermoluminescence studies of bulk CdS. The absorption spectra are observed and reported. The band gap energy of the bulk CdS corresponding to the absorption edge of pure CdS was 2.61 eV. We calculated kinetic parameters such as activation energy (E), order of kinetics (b), and frequency factor (s) with trap parameter. We found that shape factor μ in the range of 0.27–0.32 showed first-order kinetics. The value of the activation energy was 1.55–2.17 eV and the frequency factor 1.49 × 1015–6.6 × 1020 s−1.

Gd2O3 phosphor was synthesized by combustion synthesis using gadolinium nitrate hexahydrate as precursor and urea as fuel. Structural and surface morphology were studied by X-ray diffraction, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Chemical composition analysis of the phosphor was performed by Fourier-transform infrared spectroscopy, and tts optical properties were characterized by use of photoluminescence (PL) and thermoluminescence (TL) techniques. In PL spectra, feeble emission at 490 nm (blue) and intense emission at approximately 545 nm (green) are observed after excitation at 300 nm. TL measurement was performed on the Gd2O3 phosphor by irradiating it with γ-rays (1 kGy). A well resolved glow peak at 226.4 °C was observed. Kinetic data were estimated from the TL glow curve by use of Chen’s peak-shape method; the results are discussed in detail. The average particle size of the Gd2O3 phosphor was 41 nm; a monoclinic phase was formed at a firing temperature of 500 °C. This was in agreement with SEM and TEM results.

In this paper we report the synthesis of CdS:Cu nanoparticles by chemical precipitation. The structure and thermoluminescence (TL) properties of the particles were studied. TL glow curves and kinetic data, for example activation energy, order of kinetics, and frequency factor of the nanoparticles, were determined for different UV exposure times. TL glow curves were recorded for different doses of UV exposure time at a heating rate of 10 ° s−1. TL glow peaks were observed at 241.2, 252.3, and 275.3 °C when the particles were exposed to UV for 5, 10, and 15 min. Kinetic data for the synthesized nanophosphor CdS:Cu were calculated by use of the peak-shape method; trap depth was also calculated, by use of different formulae. XRD results showed the sample has a cubic structure. The average particle size was 35 nm. The Miller indices were also obtained.

The present paper reports thermoluminescence (TL) glow curves of Eu3+-doped Y2O3 phosphor with different ultraviolet (UV) exposure times. The glow peak shows second-order kinetics of Eu3+-doped Y2O3, and corresponding kinetic parameters were evaluated using the peak shape method. Calculations of trap depth were carried out using different methods. The kinetics order, activation energy, and frequency factor were calculated. The recorded glow curve shifts towards higher intensity with longer UV exposure. The heating rate used for recording TL was 3.0 °C s−1. Particle size and structure were verified by X-ray diffraction (XRD) pattern and morphology by scanning electron microscopy (SEM) imaging.

CdS:Cu nanoparticles were successfully synthesized by a coprecipitation method using mercaptoethanol as a capping agent. Thermoluminescence (TL) spectra of CdS:Cu nanoparticles were studied for different exposure time. The synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis spectrometry. XRD and SEM measurements showed that the size of the crystallites was in the range 8–17 nm. Optical measurements indicated a blue-shift in the absorption band edge upon Cu doping. The direct allowed bandgap of undoped and Cu-doped CdS nanoparticles was 2.53 and 2.64 eV, respectively. We also calculated the kinetic parameters for Cu-doped CdS nanoparticles from the TL glow curves measured at 254, 249, and 244 °C with variation of the ultra-violet (UV) exposure time. The glow curve shows general order kinetics, and its kinetic parameters are calculated.