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Enhancing the thermoelectric transport properties of conductive polymer materials has been a long-term challenge, in spite of the success seen with molecular doping strategies. However, the strong coupling between the thermopower and the electrical conductivity limits thermoelectric performance. Here, we use polaron interfacial occupied entropy engineering to break through this intercoupling for a PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonate)) thin film by using photochromic diarylethene (DAE) dopants coupled with UV-light modulation. With a 10-fold enhancement of the thermopower from 13.5 μV K−1 to 135.4 μV K−1 and almost unchanged electrical conductivity, the DAE-doped PEDOT:PSS thin film achieved an extremely high power factor of 521.28 μW m−1 K−2 from an original value of 6.78 μW m−1 K−2. The thermopower was positively correlated with the UV-light intensity but decreased with increasing temperature, indicating resonant coupling between the planar closed DAE molecule and PEDOT. Both the experiments and theoretical calculations consistently confirmed the formation of an interface state due to this resonant coupling. Interfacial entropy engineering of polarons could play a critical role in enhancing the thermoelectric performance of the organic film. [ABSTRACT FROM AUTHOR]

The thermoelectric figure of merit ZT bridges the efficiency and material parameters for a thermoelectric device operating under constant temperature of the hot‐ and cold‐source thermal boundary (Type‐I TB). However, many application scenarios fall under the constant heat‐in flux (qh) and constant cold‐source temperature (Tc) thermal boundary (Type‐II TB), for which a figure of merit is absent for more than half a century. This study aims to fill this gap and propose a figure of merit ZQD for the thermoelectric devices under the Type‐II TB condition, defined as ZQD=(ZTcZTc+1)(hκ)(qhTc)$Z{Q}_{\mathrm{D}} = ({\frac{{Z{T}_{\mathrm{c}}}}{{Z{T}_{\mathrm{c}} + 1}}})({\frac{h}{\kappa }})({\frac{{{q}_{\mathrm{h}}}}{{{T}_{\mathrm{c}}}}})$, where Z, h, and κ are the traditional figure of merit, leg height, and thermal conductivity, respectively. The effectiveness of ZQD is verified through both numerical calculations and experiments, which are more accurate and practical than ZT. Furthermore, a system‐level figure of merit ZQS is suggested after considering the external thermal resistance. Finally, optimization strategies for thermoelectric systems based on ZQS are proposed, showing a 30% enhancement in the efficiency. ZQD and ZQS are expected to be widely used in the thermoelectric field. [ABSTRACT FROM AUTHOR]

Currently, Faraday isolators and rotators for high‐power lasers are popular research topics; therefore, finding magneto‐optical materials with excellent Verdet constants and thermal properties is crucial. In this study, novel holmium scandium aluminum garnet (HoSAG) magneto‐optical ceramics were fabricated using vacuum sintering. This study improved the traditional ball milling method and pre‐synthesized powders with great sinterability after secondary ball milling and sieving. Different pre‐synthesis temperatures were found to have significant effects on the particle size and micromorphology of the synthesized powders. HoSAG ceramics with 0.05 wt% MgO sintering aid and held at 1700°C for 30 h reached a transmittance of 76.7% at 1550 nm. Meanwhile, HoSAG transparent ceramics maintain higher transmittance in the infrared region (>1500 nm) than terbium gallium garnet (TGG) crystals, indicating better application prospects. The Verdet constants of HoSAG magneto‐optical ceramics at 405, 532, 808, and 1064 nm were −421.5, −181.2, −65, and −32.3 rad T−1 m−1, respectively, which are slightly less than those of TGG magneto‐optical ceramics. Moreover, the thermal conductivity of HoSAG ceramics at 300.00 K was 4.89 W m−1 K−1, which is comparable to that of the TGG ceramics. [ABSTRACT FROM AUTHOR]

Semiconductor‐based X‐ray detectors with low detectable thresholds become critical in medical radiography applications. However, their performance is generally limited by intrinsic defects or unresolved issues of materials, and developing a novel scintillation semiconductor for low‐dose X‐ray detection is a highly urgent objective. Herein, a high‐quality rare‐earth iodate Tm(IO3)3 single crystal grown through low‐cost solution processing is reported with a wide bandgap of 4.1 eV and a large atomic number of 53.2. The roles of IO and TmO groups for charge transport in the Tm(IO3)3 are revealed with the structural difference between the [101] and [1¯01]$[{\bar{1}}01]$ crystal orientations. Based on anisotropic responses of material properties and detection performances, it is found that the [1¯01${\bar{1}}01$] orientation, the path with fewer IO groups, achieves a high resistivity of 1.02 × 1011 Ω cm. Consequently, a single‐crystal detector exhibits a low dark current and small baseline drifting due to the wide bandgap, high resistivity and less ion migration of Tm(IO3)3, resulting in a low detection limit of 85.2 nGyair s−1. An excellent X‐ray imaging performance with a high sensitivity of 4406.6 µC Gyair−1 cm−2 is also shown in the Tm(IO3)3 device. These findings provide a new material design perspective for high‐performance X‐ray imaging applications. [ABSTRACT FROM AUTHOR]

Scintillator glasses have the potential for X-ray imaging owing to their low production cost, controllable shape and size, and uniform ion-doping concentration. In this study, Tb3+-doped and Ce3+/Tb3+-co-doped oxyfluoride scintillator (C4T9) glass samples were fabricated by high-temperature melting and quenching. In addition, the luminescence properties of the glass samples and the discrepancy in the energy transfer mechanism between Ce3+ and Tb3+ under ultraviolet (UV) light and X-ray excitation were investigated. The C4T9 glass sample showed excellent integral scintillation efficiency of 84.1% for commercial Bi 4 Ge 3 O 12 (BGO) crystals. The spatial resolution of the C4T9 glass sample was higher than that of the commercial BGO crystal with 42.29 mGy s−1 X-ray irradiation, reaching 16 lp·mm−1. C4T9 glass is expected to become a key material in medical imaging, safety inspection, industrial inspection, and other fields. [ABSTRACT FROM AUTHOR]

Magneto-optical materials with high Verdet constants at high extinction ratios are desirable for the Faraday isolators. However, current terbium-based crystals have encountered several issues, such as low Verdet constants (TGG crystals), difficult growth (TSAG crystals), and low utilization of raw materials, which limit the development of the Faraday isolators. Here, R 0.0025 TSAG (R= Pr, Ho, Dy, Eu) transparent ceramics are prepared. The ceramics exhibit high optical transparency above 74.0% in the 525–1565 nm range and a high relative density of 98.9%. In particular, the transmittance of R 0.0025 TSAG ceramics at 1064 nm is approximately 81.6%, 81.6%, 79.8%, and 80.6%, respectively. The Verdet constants of R 0.0025 TSAG ceramics at the measurement wavelength are greater than those of the TSAG ceramic. The compelling magneto-optical performance of the Dy 0.0025 TSAG ceramic includes a high Verdet constant of 161.8 ± 3 rad·m−1·T−1 at 635 nm. The Verdet constant of the Dy 0.0025 TSAG ceramic is still superior to that of TSAG ceramic in the same temperature range. The extinction ratios of the R 0.0025 TSAG (R= Pr, Ho, Dy) ceramics exceed 40 dB. The figure of merit points out the superior characteristics of R 0.0025 TSAG ceramics. Moreover, R 0.0025 TSAG (R= Pr, Ho, Dy) ceramics with a thickness above the centimeter level are successfully prepared. This work indicates that the Dy 0.0025 TSAG ceramic can promote the miniaturization of magneto-optical isolators and can be applied in high-power lasers. • (Tb 0.9975 R 0.0025) 3 Sc 2 Al 3 O 12 (R= Pr, Ho, Dy, Eu) transparent ceramics were synthesized and characterized. • The Verdet constants of R-TSAG ceramics at the measurement wavelength are greater than that of TSAG ceramic. • The values of extinction ratio for R-TSAG (R= Pr, Ho, Dy) ceramics exceed 40 dB. [ABSTRACT FROM AUTHOR]

To generate continuous velocity, acceleration and jerk curves of parametric interpolation in high-speed and high-accuracy machining, this paper presents a trigonometric velocity scheduling algorithm based on two-time look-ahead interpolation (pre-interpolation and look-ahead interpolation). The algorithm consists of three modules: pre-interpolation, look-ahead interpolation and real-time interpolation. The pre-interpolation module aims to explore and record the information of the path to be machined. The look-ahead interpolation module firstly calculates the velocity scheduling functions according to the data recorded by pre-interpolation, and then tests and adjusts the feedrate scheduling schemes constantly. The real-time interpolation module adapts the method of beforehand deceleration or delaying acceleration according to the signals received from pre-interpolation and look-ahead interpolation to guarantee the processing accuracy. Simulation and experimental tests demonstrate the availability, effectiveness and advantages of the trigonometric velocity scheduling algorithm. And the proposed trigonometric velocity scheduling algorithm based on pre-interpolation and look-ahead interpolation could realize smooth velocity, acceleration and jerk control with restricted chord error and implement high-quality CNC processing. [ABSTRACT FROM AUTHOR]

Scintillators play a vital role in high-energy physics, medical imaging, security inspection, etc. Here, we designed and prepared a highly efficient scintillator of Ce,Tb-codoped LiLuF 4 , which was synthesized by a hydrothermal method using low-cost raw materials. The microcrystalline scintillator exhibits the strong luminescence of rare earth ion, which has a characteristic green fluorescence emission with a quantum yield of 71.59%. This material has a strong X-ray response, superior light output (16,509 ph/MeV), excellent ray cut-off capability and absolute stability. Based on micron-level powdered compounds, we used direct coating to manufacture a scintillation film with a size of 5.5 cm × 8.0 cm for X-ray imaging testing. The imaging test shows that the highly stable scintillation film not only has a spatial resolution capability of more than 10.0 LP/mm but also has great potential to be prepared as a flexible scintillator, which exhibited excellent performance as an potential scintillation detection material. Tetragonal LLF:Ce,Tb MCs exhibit bright and sensitive radioluminescence with the energy transfer process between rare earth ions, and its composite film can provide a decent spatial resolution for X-ray imaging applications. [Display omitted] • Lu element was used instead of Y element to improve the scintillation property of the material. • Ce ion sensitizing Tb ion strategy was adopted to improve the radiation light output of the material. • A large area scintillation film with transmittance of 79.92% was successfully prepared by direct coating method. • The spatial resolution of the scintillation film for radiation detection is more than 10.0 LP/mm. [ABSTRACT FROM AUTHOR]