Photochromism‐induced light scattering and photoswithing in Er doped (K,Na)NbO₃ transparent ceramics

Abstract

The (K0.5Na0.5)0.95Li0.05Nb0.95Bi0.05O3‐1mol% Er2O3 transparent ceramics were prepared by a pressureless sintering method. The fabricated transparent ceramics not only exhibit high optical transmittance (85.3%) due to dense microstructure (nanoscale size grains), but also show the photochromism‐induced light scattering and reversible upconversion (UC)‐switching properties by visible light irradiation. Upon 407 nm light irradiation, the optical transmittance intensity is significantly decreased, showing a strong light scattering (ΔAbs = 28.3%). The light scatting degree can be quantitatively reflected by Er3+ ion UC emission, and could be recovered to its initial optical transmittance based on photochromic reactions. Meanwhile, the transparent ceramic is found to maintain good energy storage properties with higher W (5.87 J/cm3) and Wrec (1.96 J/cm3) under a higher electric field of 260 kV/cm. These results suggest that Er3+ doped (K0.5Na0.5)NbO3 transparent ceramics are promising for the modulation of light scattering and the design of photoelectric multifunction devices.

Thermal Kinetics and Theoretical Third Order Nonlinear Optical Susceptibility of some As2 O3 .V2 O5 .FeO Glasses

“…Based on Sun's fundamental condition of glass formation, [29] Dimitrov et al, [30] proposed a simple method to calculate the average single bond strength B M─O of oxide glasses. The B M─O formalism for the glass system under investigation can be written as follows:…”

“…These moderate values of B M─O may suggest that the covalent character is dominant between the bonds formed in the glass structure and also reflects their high tendency of forming glass. According to Sun [29,31] high value of B M─O increases the glass forming tendency. Ionic character with B M─O % 251.2-253.7 kJ mol À1 is given for ZnO─BaO─V 2 O 5 glasses, [17] large B M─O % 390-403 kJ mol À1 is recorded for Na 2 O─B 2 O 3 ─SiO 2 glasses [33] which may arise due to the high bond strength offered by Si─O and B─O bonds (B Si─O ¼ 443 kJ mol À1 and B B─O ¼ 498 kJ mol À1 ) and reflects their metallic nature.…”

Highly Responsive Photochromic Ceramics for High‐Contrast Rewritable Information Displays

“…Recently, KNN-based ceramics have attracted much research interest in photochromic application due to the relatively low phonon energy, high thermal resistance, and good chemical stability. [34][35][36][37] Therefore, the benchmark KNN ceramic was selected as the matrix material to verify this strategy and both Al 3+ and Eu 3+ were introduced into KNN to tailor the traps. Compared to other doped KNN-based ceramics, the incorporation of Eu 3+ ions generated deeper traps, resulting in both a fast response time of around 1 s and a strong coloration contrast of 39.2%.…”

Smart white lighting and multi‐mode optical modulations via photochromism in Dy‐doped KNN‐based transparent ceramics

“…Lead‐free (K 0.5 Na 0.5 )NbO 3 ceramics are famous for superior piezoelectricity and ferroelectricity, simultaneously they are considered as ideal photoluminescence (PL) host due to relatively low phonon energy (~750 cm −1 ), high thermal resistance, good durability, and physical/chemical stability 12,13 . Thereinto, some rare earth ion (RE 3+ ) doped KNN‐based transparent ceramics possess photochromic (PC) behavior, reversible PL, and optical transmittance modulating capability, showing application potential in information display devices, optical anti‐fake labels, and photo‐switches 14–16 . Additionally, RE 3 + ‐doped materials can emit light in the form of lenses, which promote the direct packaging of LED chips 17,18 .…”

“…12,13 Thereinto, some rare earth ion (RE 3+ ) doped KNN-based transparent ceramics possess photochromic (PC) behavior, reversible PL, and optical transmittance modulating capability, showing application potential in information display devices, optical anti-fake labels, and photo-switches. [14][15][16] Additionally, RE 3+ -doped materials can emit light in the form of lenses, which promote the direct packaging of LED chips. 17,18 However, to the best of our knowledge, KNN-based PL ceramics used for LEDs have rarely been mentioned.…”