A Novel 1D Organic Lead Halide Hybrid for Blue and White Dual Emission

In recent years, photoelectric performances of many low-dimensional metal halide hybrid materials have been researched and utilized in the domain of phosphors, light emitting diodes (LEDs) and photoelectric detection etc. Nevertheless, unlike two-dimensional (2D) ones, one-dimensional (1D) hybrids received less attention to study their structures and optical properties. Herein, we deal with luminous performance and photoluminescence mechanism for an original 1D organic-inorganic lead chloride hybrid C5H14N3PbCl3 which is abbreviated as TMGPbCl3 (TMG+ = 1, 1, 3, 3-tetramethyguanidine cation). According to photoluminescence spectra, its broadband white-light luminescence are dual emissions from organic component TMG+ peaked at 429 nm and self-trapped excitons (STEs) of inorganic metal halide octahedra peaked at 510 nm, respectively and this property make it to be a promising white-light phosphor.

State of the Art in Crystallization of LiNbO3 and Their Applications

Lithium niobate (LiNbO3) crystals are important dielectric and ferroelectric materials, which are widely used in acoustics, optic, and optoelectrical devices. The physical and chemical properties of LiNbO3 are dependent on microstructures, defects, compositions, and dimensions. In this review, we first discussed the crystal and defect structures of LiNbO3, then the crystallization of LiNbO3 single crystal, and the measuring methods of Li content were introduced to reveal reason of growing congruent LiNbO3 and variable Li/Nb ratios. Afterwards, this review provides a summary about traditional and non-traditional applications of LiNbO3 crystals. The development of rare earth doped LiNbO3 used in illumination, and fluorescence temperature sensing was reviewed. In addition to radio-frequency applications, surface acoustic wave devices applied in high temperature sensor and solid-state physics were discussed. Thanks to its properties of spontaneous ferroelectric polarization, and high chemical stability, LiNbO3 crystals showed enhanced performances in photoelectric detection, electrocatalysis, and battery. Furthermore, domain engineering, memristors, sensors, and harvesters with the use of LiNbO3 crystals were formulated. The review is concluded with an outlook of challenges and potential payoff for finding novel LiNbO3 applications.

Fast and controllable synthesis of AB-stacked bilayer MoS2 for photoelectric detection

In recent years, researchers have explored the interlayer stacking structure of the bilayer (BL) transition metal dichalcogenides (TMDCs) and found that it has unique impact on the electrical, optical, and vibrational properties of TMDCs. Unfortunately, the size of BL TMDCs synthesized by the pre-existing methods is not large. In addition, there is not any effective mean to control the number of layers as well as the stack structure. This is the major limiting factor for further exploration of the properties of BL TMDCs. We report a new method for the rapid and controllable growth of AB-stacked BL MoS2. Firstly, the mixed solution of Na2MoO4 and NaOH was spun on the sapphire substrate and then sulfurated. The BL MoS2 of AB-stacked can be obtained by changing the time of sulfur introduction. The size of the BL MoS2 is related to the parameters of sulfur. The maximum size of BL MoS2 grown by this method can reach 288 μm, and the average size can reach about 200 μm, which is larger than the size reported in most articles. In addition, the growth rate of BL MoS2 can be clearly increased by the spin-coating growth method and the fastest growth rate is up to 144 μm/min, which is far higher than other published reports at present. Subsequently, a photodetector based on BL MoS2 was prepared. The response time of rising edge is about 0.32 ms, and that of falling edge is about 3.2 ms. The detector prepared by us shows excellent photoelectric detection performance. Therefore, the excellent performance of BL MoS2 makes it have a broad application prospect in the field of high-performance electronics and optoelectronics.

Image coding by count sample, motivated by the mechanisms of light perception in the human visual system.

The paper presents the results of a study of input video data adequate formation/coding in modern imaging systems. Adequacy is understood here as the maximal correspondence between the ways of the radiation registration by material detectors and the ways of data coding in the retina of the human visual system. In this connection, the paper discusses general statistical issues of (photo) counts photoelectric detection and, on this basis, formalizes the concept of an ideal image formation by (ideal) visualization device. The problems arising in practice when working directly with ideal images are discussed and a method of their reduction to count sample of fixed (controllable) size, which, in fact, constitute the representation (coding) of registered data, is proposed. Results of illustrative computational experiments on count coding of the common digital images given by pixel data are presented. Examples of count samples of different sizes generated for the tested digital image are given. Based on the given results, the dependence of characteristics of sampling representations on the parameter of sample size is discussed.