Influence of Ce, Pr, and Gd Doping on Optical and Electrochemical Energy Storage Capabilities of Ca_0.15Zr_0.85O_1.85

Sharma A., Sharma S.K.

In this investigation, we have examined how different excitation wavelengths affect charge storage in Cr doped Zn2TiO4.

James J., Sharma A., Hussain S., Sharma S.K.

Maier J.G., Gadelmawla A., Khansur N.H., Webber K.G.

In this study, the stress-modulated energy storage properties of lead-free polycrystalline Ba0.85Ca0.15Zr0.1Ti0.9O3 was investigated as a function of temperature from 25 °C to 55 °C. The externally applied uniaxial compressive stress of −160 MPa increased the recoverable energy storage density by 226% to a maximum value of 274 mJ/cm3, in addition to enhancing the energy storage efficiency by approximately 10% to a value of 88.2%. The macroscopic mechanical constitutive behavior is presented as well as the stress-dependent dielectric and ferroelectric properties and the Rayleigh behavior in order to elucidate the effect of stress on the energy storage properties. Importantly, the stress-induced tailoring of energy storage performance can be utilized for other nonlinear dielectric ceramics to tune their extrinsic polarization mechanisms to significantly enhance the recoverable energy density and reduce the hysteretic losses.

Sharma S.K., James J., Gupta S.K., Hussain S.

The nearly dormant field of persistent luminescence has gained fresh impetus after the discovery of strontium aluminate persistent luminescence phosphor in 1996. Several efforts have been put in to prepare efficient, long decay, persistent luminescent materials which can be used for different applications. The most explored among all are the materials which emit in the visible wavelength region, 400–650 nm, of the electromagnetic spectrum. However, since 2014, the wavelength range is extended further above 650 nm for biological applications due to easily distinguishable signal between luminescent probe and the auto-fluorescence. Recently, UV-emitting persistent materials have gained interest among researchers’ due to their possible application in information storage, phototherapy and photocatalysis. In the present review, we summarize these recent developments on the UV-emitting persistent luminescent materials to motivate young minds working in the field of luminescent materials.

Wang C., Jin Y., Zhang R., Yuan L., Li Z., Wu H., Chen L., Hu Y.

• Bi 3+ emission is for the first time tuned controllably and finely within UVB full-spectrum. • UVB persistent luminescence can last more than 72 h. • Tunable UVB optically stimulated luminescence can be repeatedly revitalized by external NIR light. • The application for high-secure data encryption and decryption using 8-bit ASCII binary codes is demonstrated. The ultraviolet-B (UVB) delayed luminescence materials, holding great potential in the field of phototherapy, sterilization, photocatalysis and anti-counterfeiting, however, lack of spectral tunability study and restricted to limited persistent time. In this paper, a series of Bi 3+ -doped garnet phosphors were successfully synthesized and the Bi 3+ emission is for the first time tuned controllably and finely within UVB full-spectrum. The continuous replacement of Ga 3+ by Al 3+ ions gives rise to a fine blue-shift of Bi 3+ emission from 313 to 302 nm due to the greater covalency of the Ga O bond. Driven by the increased symmetry of the dodecahedron, it is further shifted to a much shorter wavelength step-by-step and finally approached to 298 nm with the progressive substitution of Y 3+ by Lu 3+ ions. The developed Bi 3+ -doped phosphors show delayed UVB luminescence, of which the persistent time can be optimized to more than 72 h by the effective combination of bandgap engineering and trap engineering strategies. Moreover, excellent optically stimulated luminescence that the UVB persistent luminescence of the pre-irradiated phosphor can be repeatedly revitalized by a low-energy 870 nm near-infrared (NIR) LED light source. As a proof-of-concept, invisible characters of UV write-in and NIR read-out for high-secure data encryption and decryption application using 8-bit ASCII binary codes were implemented. This work not only offers the path for the development of novel UVB phosphors with desired emission wavelength but also extends the applications of UVB delayed luminescence materials.

Karamova A.E., Verbenko D.A., Vorontsova A.A., Zhilova M.B., Nikonorov A.A., Gatiatulina E.R., Znamenskaya L.F., Kubanov A.A.

Background. Mycosis fungoides (MF) is the most common subtype of cutaneous T-cell lymphoma. The aim of the present study was to produce up-to-date information on different phototherapy approaches on skin cytokines in patients with MF. Methods. A total of 27 patients with mycosis fungoides were treated with phototherapy: NB-UVB (narrow‐band ultraviolet B therapy) (10 patients) and PUVA (long-wavelength ultraviolet radiation of spectrum A with the use of skin-photosensitizing furocoumarins) therapy (17 patients). Evaluation of the effectiveness of treatment was carried out using BSA (body surface area) and the modified assessment of the severity of the skin lesions scale (mSWAT) used to quantify tumor mass in cutaneous T-cell lymphomas. Average numbers of procedures were 30.2 and 27.8 in the NB-UVB and PUVA groups, respectively. The median total dose of NB-UVB irradiation was 19.9 J/cm2 and PUVA therapy was 104.0 J/cm2. The overall response to therapy including complete and partial remission was 74.9% in the total group; 70% in the NB-UVB group, and 77.7% in the PUVA therapy group. In the obtained biopsies from lesions, surrounding tissue before treatment and skin samples of four healthy volunteers, the concentration of the IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, sCD40L, and TNF-α cytokines was studied. An increase in IL-4 and TNF-α levels was shown in the lesional skin of patients compared to the skin of healthy controls. After the treatment, positive correlations of mSWAT with the levels of IL22, IL33, and TNF-α in the tumor tissue were found. The levels of IL10 and IFN-γ after PUVA treatment were increased in comparison to baseline. There was no difference in cytokine levels before/after NB-UVB therapy.

Liu B., Gan W., Lou S., Zou R., Tang Q., Wang C., Jiao J., Wang J.

The development of functionalized persistent-luminescent (PersL) materials is currently receiving intense interest for diverse applications. However, PersL materials emitting ultraviolet light in the 315–400 nm (UVA) range are lacking. Herein, a series of x-ray-activated PersL materials based on ABCO4-type structures with random cation arrangements are developed. Comprehensive experiments confirm that materials featuring random cation arrangements are sufficiently general to act as host materials for PersL. Experimental results indicate that as-synthesized SrLaXO4:Bi3+ (X = Al, Ga, In) powders have tunable PersL bands covering the UV-to-visible range after x-ray irradiation. Taking advantage of the depth-independent nature of x-ray illumination in tissues, UVA Persl composites using the matched photosensitizer g-C3N4 (SrLaAlO4:Bi@g-C3N4) are well suited for x-ray-activated photodynamic therapy, as proven by tests for singlet-oxygen (1O2) generation. Therefore, we suggest that the proposed concept be applied to discover additional functionalized PersL materials for clinical cancer therapy in the future.

Han P., Lv H., Li X., Wang S., Wu Z., Li X., Mu Z., Li X., Sun C., Wei H., Ma L.

The presence of oxygen vacancy on the surface of CaZrO3 accelerates the decomposition of ozone and generates reactive oxygen substances to act on the mineralization of m-cresol.

Thakur V.N., Yadav S., Kumar A.

Basic Physics as well as devices fabrication required in-depth analysis of the effect of temperature, pressure, and other physical parameters on dielectric properties to understand the microstructure-property relation. In this regard, we have thoroughly investigated the temperature and pressure dependent ferroelectric, dielectric, and impedance properties of Bi-substituted Pb1-xBi2x/3(Zr0.52Ti0.48)O3 (PBiZT) (x = 0.10 to 0.40) ceramics. The maximum solubility of Bi was found near x = 0.15, and above this composition, it shows a composite phase of PBiZT and ZrO2. The remanent polarization (Pr) increases with decrease in the Bi concentration with the maximum value obtained for x = 0.15, i.e., 40 μC/cm2. Temperature-dependent dielectric constant and tangent loss were measured as function of composition to check the ferroelectric phase transition temperature (Tc) and the operating temperature limit for the material to make a device. The Tc value increases with decrease in bismuth (Bi) concentration which obtained in the range of 350 ℃ - 375 ℃. The tangent loss was observed to be near about 0.01 to 0.03 below 200 ℃ which suggests its suitability for device applications. The temperature-dependent imaginary part of impedance ( Z ' ' ) was measured at various temperatures with varying frequency in the range of 100 Hz – 1 MHz. The peaks positions of the Z ' ' vs. frequency shift towards lower temperature side with increasing the value of x from 0.1 to 0.4 near and above Tc. The pressure-dependent dielectric constant ( e r ) and capacitive reactance ( X c ) were also measured for varying x, and it was observed that maximum change in e r and X c was observed for x = 0.15 i.e. 13% and 10.5%, respectively. The pressure sensitivity was obtained maximum for the composition near the maximum solubility of Bi in PbZr1-xTixO3 (PZT) matrix. The reason behind getting the highest remanent polarization and pressure sensitivity for x = 0.15 is that of the highest piezoelectric coefficients ∼ 130 pC/N.

Sun H., Gao Q., Wang A., Liu Y., Wang X., Liu F.

Ultraviolet persistent luminescence technology holds potential for some new applications where ultraviolet emission is needed but constant external excitation is unavailable. Despite the promising applications, not much is known about such luminescence. Here we report ultraviolet-B (290−320 nm) persistent luminescence phenomenon in isostructural Y3Ga5O12:Bi3+ and Y3Al5O12:Bi3+ phosphors. We further investigate the luminescence by measuring thermoluminescence of the two phosphors. Our spectral results indicate that conventional thermoluminescence measurement cannot directly evaluate the electron population in the traps of Y3Ga5O12:Bi3+, in which the ultraviolet emission is suppressed at high temperature due to a thermal ionization quenching. We believe that the insight of the present trap performance is transferable to other ultraviolet persistent phosphors.

Li H., Liu Q., Ma J., Feng Z., Liu J., Zhao Q., Kuroiwa Y., Moriyoshi C., Ye B., Zhang J., Duan C., Sun H.

Sharma S.K., Bettinelli M., Carrasco I., Beyer J., Gloaguen R., Heitmann J.

The optical and persistent luminescence properties of CaB2O4:Ce3+ phosphor are presented. The optical emission for excitation in the 250–340 nm wavelength region is dominated by two bands at 365 and 460 nm. Lifetime measurements suggested that the 365 nm emission band is due to interconfigurational Ce3+ 5d → 4f transitions. Upon excitation with a 254 nm UV lamp, a superlong persistent luminescence in the UVA1 region (340–400 nm, blacklight) was observed, lasting for at least 15 h, and with excellent reproducibility, which is perfectly suitable for phototherapy application. The initial-rise method was applied on the thermoluminescence glow curves to determine the trap distribution and trap depth. The results suggest that one distinct trap, with an activation energy of ∼0.52 eV, was solely responsible for the persistent luminescence in the CaB2O4:Ce3+ phosphor. The other traps had a quasi-continuous distribution, with activation energies between 0.56 and 1.15 eV. The proposed persistent luminescence and the...

Jiang B., Iocozzia J., Zhao L., Zhang H., Harn Y., Chen Y., Lin Z.

The successful production of nanostructured BaTiO3enables theoretical and experimental investigation into the intriguing yet complex dielectric properties of individual BaTiO3nanocrystals. By combining BaTiO3nanocrystals and certain polymers, the resulting BaTiO3/polymer nanocomposites possess many advantages from both components.

Xu J., Tanabe S.

Great progress has been made in inorganic persistent phosphors, especially in the recent two decades, motivated by the discoveries of the SrAl2O4:Eu2+-Dy3+ in the green and Cr3+ doped spinel compounds in the deep-red to near-infrared (NIR) spectral regions. However, the physical mechanism behind this kind of “self-sustained” luminescence is still the subject of debate, and the improvement of known persistent phosphors and/or the development of new ones are still a matter of trial-and-error. In this review, starting from the introduction of longstanding histories of persistent luminescence (PersL), we provide comprehensive insights into its physical mechanism. Particular focus is put on the state-of-the-art of designing new persistent phosphors via “bandgap engineering”, based on the knowledge about trapping-detrapping mechanisms of charge carriers and energy level locations of emitting/trapping centers. Recent significant works on PersL observed in organic molecules and phosphorescence observed in inorganic phosphors are also highlighted in order to give a clear distinction between these two long-lived luminescence phenomena. Key challenges, feasible improvements and perspectives of PersL working in the ultraviolent (UV), white, red and NIR (over 1000 nm) regions together with new charging concepts by NIR or visible-light lasers are also presented. It is hoped that this review could give new inspiration for the future development of PersL in emerging applications.

Sun S., Wang H., Yan X.

Persistent luminescence nanoparticles (PLNPs) are unique optical materials emitting long-lasting luminescence after ceasing excitation. Such a unique optical feature allows luminescence detection without constant external illumination to avoid the interferences of autofluorescence and scattering light from biological fluids and tissues. Besides, near-infrared (NIR) PLNPs have advantages of deep penetration and the reactivation of the persistent luminescence (PL) by red or NIR light. These features make the application of NIR-emitting PLNPs in long-term bioimaging no longer limited by the lifetime of PL. To take full advantage of PLNPs for biological applications, the versatile strategies for bridging PLNPs and biological system become increasingly significant for the design of PLNPs-based nanoprobes. In this Account, we summarize our systematic achievements in the biological applications of PLNPs from biosensing/bioimaging to theranostics with emphasizing the engineering strategies for fabricating specific PLNPs-based nanoprobes. We take surface engineering and manipulating energy transfer as the major principles to design various PLNPs-based nanoprobes based on the nature of interactions between nanoprobes and targets. We have developed target-induced formation or interruption of fluorescence resonance energy transfer systems for autofluorescence-free biosensing and imaging of cancer biomarkers. We have decorated single or dual targeting ligands on PLNPs for tumor-targeted imaging, and integrated other modal imaging agents into PLNPs for multimodal imaging. We have also employed specific functionalization for various biomedical applications including chemotherapy, photodynamic therapy, photothermal therapy, stem cells tracking and PL imaging-guided gene therapy. Besides, we have modified PLNPs with multiple functional units to achieve challenging metastatic tumor theranostics. The proposed design principle and comprehensive strategies show great potential in guiding the design of PLNPs nanoprobes and promoting further development of PLNPs in the fields of biological science and medicine. We conclude this Account by outlining the future directions to further promote the practical application of PLNPs. The novel protocols for the synthesis of small-size, monodisperse, and water-soluble PLNPs with high NIR PL intensity and superlong afterglow are the vibrant directions for the biomedical applications of PLNPs. In-depth theories and evidence on luminescence mechanism of PLNPs are highly desired for further improvement of their luminescence performance. Furthermore, other irradiations without tissue penetrating depth limit, such as X-ray, are encouraged for use in energy storage and re-excitation of PLNPs, enabling imaging in deep tissue in vivo and integrating other X-ray sensitized theranostic techniques such as computed tomography imaging and radiotherapy. Last but not least, PLNPs-based nanoprobes and the brand new hybrids of PLNPs with other nanomaterials show a bright prospect for accurate diagnosis and efficient treatment of diseases besides tumors.