China Academy of Engineering Physics

About: China Academy of Engineering Physics is a facility organization based out in Mianyang, China. It is known for research contribution in the topics: Laser & Microstructure. The organization has 14158 authors who have published 12055 publications receiving 115810 citations. The organization is also known as: Ninth Institute of Second Ministry of Mechanical Industry & Ninth Institute of Ministry of Nuclear Industry.

Unexpected Sole Enol‐Form Emission of 2‐(2′‐Hydroxyphenyl)oxazoles for Highly Efficient Deep‐Blue‐Emitting Organic Electroluminescent Devices

Abstract: Considerable efforts have been devoted to the development of highly efficient blue light-emitting materials. However, deep-blue fluorescence materials that can satisfy the Commission Internationale de l'Eclairage (CIE) coordinates of (0.14, 0.08) of the National Television System Committee (NTSC) standard blue and, moreover, possess a high external quantum efficiency (EQE) over 5%, remain scarce. Here, the unusual luminescence properties of triphenylamine-bearing 2-(2′-hydroxyphenyl)oxazoles (3a–3c) and their applications in organic light-emitting diodes (OLEDs) are reported as highly efficient deep-blue emitters. The 3a-based device exhibits a high spectral stability and an excellent color purity with a narrow full-width at half-maximum of 53 nm and the CIE coordinates of (0.15, 0.08), which is very close to the NTSC standard blue. The exciton utilization of the device closes to 100%, exceeding the theoretical limit of 25% in conventional fluorescent OLEDs. Experimental data and theoretical calculations demonstrate that 3a possesses a highly hybridized local and charge-transfer excited state character. In OLEDs, 3a exhibits a maximum luminance of 9054 cd m−2 and an EQE up to 7.1%, which is the first example of highly efficient blue OLEDs based on the sole enol-form emission of 2-(2′-hydroxyphenyl)azoles.

Ghost spintronic THz-emitter-array microscope.

Abstract: Terahertz (THz) waves show great potential in nondestructive testing, biodetection and cancer imaging. Despite recent progress in THz wave near-field probes/apertures enabling raster scanning of an object’s surface, an efficient, nonscanning, noninvasive, deep subdiffraction imaging technique remains challenging. Here, we demonstrate THz near-field microscopy using a reconfigurable spintronic THz emitter array (STEA) based on the computational ghost imaging principle. By illuminating an object with the reconfigurable STEA followed by computing the correlation, we can reconstruct an image of the object with deep subdiffraction resolution. By applying an external magnetic field, in-line polarization rotation of the THz wave is realized, making the fused image contrast polarization-free. Time-of-flight (TOF) measurements of coherent THz pulses further enable objects at different distances or depths to be resolved. The demonstrated ghost spintronic THz-emitter-array microscope (GHOSTEAM) is a radically novel imaging tool for THz near-field imaging, opening paradigm-shifting opportunities for nonintrusive label-free bioimaging in a broadband frequency range from 0.1 to 30 THz (namely, 3.3–1000 cm−1). A modification of the technology called terahertz near-field microscopy brings improvements in resolution and speed for biological and medical imaging and nondestructive materials testing. Terahertz waves lie between the microwave and infra-red regions of the electromagnetic spectrum. The improved ‘ghost-imaging’ procedure was developed by researchers in China, Singapore and the USA, led by Li-Guo Zhu at the China Academy of Engineering Physics. In ghost imaging the illuminating radiation is split into one beam that interacts with the object being studied and another beam that does not. The so-called ghost image of the object is then constructed by computational comparison of the different behaviour of the two beams. The innovation depends on gaining enhanced control of the structure of the terahertz radiation using a system called a spintronic terahertz emitter array.

Laser Direct Writing of a High-Performance All-Graphene Humidity Sensor Working in a Novel Sensing Mode for Portable Electronics.

Abstract: This paper reports a fast and highly sensitive all-graphene humidity sensor working in a novel alternating current (ac) detection mode for the first time, which is capable of sensing humidity on a smartphone for portable electronics. The humidity sensor is based on an interdigitated reduced graphene oxide/graphene oxide/rGO (rGO/GO/rGO) structure patterned by a facile laser direct writing method. It works in an ac sensing mode with a rectangular input voltage wave and measures the output voltage wave instead of conventional resistance, impedance, or capacitance, exhibiting a dramatically enhanced sensitivity by about 45 times compared to the low and unstable response in dc mode. The humidity sensor shows an obvious response to the relative humidity (RH) ranging from RH 6.3% to RH 100%. The response and recovery toward humidity change are almost instantaneous, and the corresponding costed times including humidity rise and decay times are less than 1.9 and 3.9 s, respectively, which are among the best resul...

Peaked dielectric responses in Ti3C2 MXene nanosheets enabled composites with efficient microwave absorption

Abstract: The microwave dielectric behavior of sandwich-like Ti3C2 MXene nanosheets with efficient microwave absorption was investigated by a combination of experiments and simulations. The obvious frequency dispersion effect and the double-peaked feature of dielectric spectra in Ti3C2 MXene nanosheets could be observed over the frequency range of 2–18 GHz, giving rise to superior microwave attenuation capability. Furthermore, a revised Drude-Lorentz model was proposed to explain the peaked feature of permittivity, and simulated results were demonstrated to agree well with the experimental measurements. It was concluded that the hopping migration between Ti3C2 MXene nanosheets with longer relaxation time than “micro-dipole” relaxation within nanosheets makes a superior contribution to overall absorbing performance.