New D–A polymers with symmetric dithienocyclopentapyrenes ( PyDT ) and benzothiadiazole ( BT ) were reported. The amorphous cs-PyDT-BT showed red emission with 22% PLQY in lower M n and achieved hole mobility up to 1.03 cm 2 V −1 s −1 in medium M n .

Super Tau Charm Facility (STCF) is the third-generation e+-e- collider under design and R&D with a circumference about 860 m, a center-of-mass (CoM) energy range from 2 to 7 GeV. The facility has design luminosity higher than 0.5 & times; 10(35) cm(-2) s(-1), about 100 times higher than BEPC-II. It will provide a factory producing massive tau leptons and charm hadrons, to unravel the mystery of how quarks form matter and the symmetries of fundamental interactions. To squeeze the beam for higher luminosity, compact twin-aperture high gradient interaction region superconducting magnet (IRSM) systems are required on both sides of interaction point (IP). There are two twin-aperture superconducting quadrupoles, QD1 and QF2, in each IRSM, with design field gradients of 50 T/m and 40 T/m, respectively, and sited at a beam crossing angle of 60 mrad. Besides quadrupoles, each of the two IRSMs also consists of anti-solenoids (including screen solenoids and compensation solenoids) and orbit correctors. In this paper, technical considerations and full-size prototype designs of the first quadrupole coils QD1 are described.

High-performance solid-state lithium metal batteries capable of operating at sub-zero temperatures are desired but currently impeded by the sluggish kinetics stemming from the temperature-dependent behavior of Li+ transfer within solid electrolytes (SEs). To address this challenge, we have engineered a polyrotaxane-based fast Li-ion conductor as an innovative SE (termed PRSE-Cu), which features a metal-bridged crosslinking network within its architecture. The coordination interactions restrict the random sliding motion of the cyclic hosts, thereby forming well-ordered one-dimensional ion-conductive channels. As a result, PRSE-Cu displays enhanced Li+ conductivity. Specifically, it exhibits a high Li+ conductivity of 8.3 x 10(-4) S cm(-1) and a Li transference number of 0.75 at 25 degrees C; moreover, it boasts exceptional electrochemical stability (up to 5.0 V), and remarkable temperature adaptability (from 20 degrees C to 60 degrees C). In practical applications, a Li/PRSE-Cu/Li symmetric cell operates stably for over 4500 h at 0.1 mA cm(-2) and 25 degrees C. Notably, a Li/PRSE-Cu/LiFePO4 battery achieves stable cycling for over 1000 cycles at 0.5C and 0 degrees C, with an impressive capacity retention of 90.1 %. This study presents an innovative strategy that provides valuable insights into the design of low-temperature electrolytes and drives further advancements in solid-state Li-metal batteries.

The interface between organic semiconductors and metal electrodes remains a major challenge in organic thin-film transistors (OTFTs), which limits the transit frequency of OTFTs in logic circuits and leads to inaccurate assessment of charge transport. In this work, we propose a novel strategy to enhance interfacial contact by employing organic solid-solution films (SSFs) as buffer layers between electrodes and semiconductors. Finite organic solid-solution semiconductors, (P5)x(C8-BTBT)1-x, were successfully fabricated via coevaporation of P5 and C8-BTBT molecules. Substitutional solid solutions were formed for x < 0.5, while phase separation was observed for x ≥ 0.5. OTFTs incorporating SSFs as interfacial buffer layers effectively eliminate the nonlinear behavior of output characteristics, exhibiting a substantial reduction in contact resistance and achieving a high carrier mobility of up to 4.6 cm2/(V s). This improvement is attributed to interfacial energy level alignment and lattice matching, which significantly lower the injection barrier and reduce interfacial structural defects. Our results provide a promising approach for optimizing semiconductor/metal contacts to improve the overall performance of organic transistors.

Organic electrochemical transistors (OECTs) garner significant attention in biosensing and neuromorphic computing applications owing to their high transconductance, low operating voltage, and biocompatibility. Among the various factors influencing OECTs performance and functionality, particularly synaptic behavior emulation, ion doping/dedoping kinetics play a pivotal role. However, precise control of ion dynamics remains challenging because of the complex interplay between material properties and microstructural characteristics. In this study, we demonstrate the modulation of the ion doping dynamics and synaptic behavior of OECTs based on hydrophilic-hydrophobic block copolymers (DPP-b-g2T-T) through thermal annealing. We investigate the correlations among segmental hydrophilicity/hydrophobicity, crystallinity, and ion transport kinetics. Our findings reveal that hydrophilic g2T-T segments enhance the ion doping efficiency, whereas hydrophobic DPP segments restrict ion transport. Thermal annealing reduces the ion doping/dedoping rates for both segments, particularly Au-gated OECTs. This phenomenon is attributed to the enhanced film crystallinity, which impedes ion transport, especially under the relatively weak gate control effect characteristic of Au. Leveraging the annealing-modulated ion doping/dedoping dynamics and prolonged retention time, we emulate short-term plasticity (STP) and long-term plasticity (LTP). This work establishes a strategy for optimizing OECTs synaptic performance through synergistic molecular design and thermal annealing, contributing to the advancement of neuromorphic technology.

Constructing a solid solution is an effective strategy for regulating the properties of composite organic semiconductors. However, there presents significant challenges in fabrication and understanding of organic solid-solution semiconductors. In this study, infinite solid-solution semiconductors are successfully achieved by integrating rod-like organic molecules, thereby overcoming the limitations of current organic composite semiconductors. Within these solid solutions, one type of molecule are incorporated into the crystalline lattice of another through random substitution. The continuous evolution in film morphology, crystalline lattice parameters and physical properties are observed as component ratios vary, accompanying with changes in the growth behavior of films. Molecular-level intercalation is evidenced by Davydov splitting, photoluminescence spectroscopy, and optical absorption analyses. Moreover, the continuous variation in ionization potential is demonstrated through organic Schottky diodes. This advancement in organic solid solutions can not only satisfy diverse requirements for device fabrication but also facilitate novel designs in device architecture.

The mechanism of acceleration of the phase transition of isotactic polybutene-1 (iPB-1) from form II to form I during solvent vapor annealing was explored by in situ wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) techniques. During n-hexane vapor annealing, the (200) and (213) diffraction peaks of form II in WAXD shift toward lower angles first and then backward to larger angles. The phenomenon suggests that substantial internal stress is generated within the sample during solvent vapor annealing. The internal stress was quantitatively characterized using an elastic model, showing an initial increase to 0.6 MPa over time, followed by a decrease and stabilization at a plateau of 0.2 MPa. Unexpectedly, the internal stress introduced by the solvent vapor exerted compression along the c-axis and inhibition in the a,b-axis, hindering the phase transition. Indeed, the penetration of solvent molecules into the amorphous region causes expansion and induces disentanglement, thereby weakening the stabilizing effect of form II and creating favorable conditions for the rapid transition to form I.

Liquid crystal elastomers (LCEs) have attracted wide interest due to their characteristic large strain in actuation. However, their high transition temperatures to the isotropic phase (TI) and poor mechanical strength still limit their applications. Here, an LCE network was modified with poly(ethylene glycol) soft segments to lower its TI, which was adjusted close to body temperature. Additionally, a mesh-structured power-net fabric in a prestretched state was introduced into the LCE matrix to reinforce the soft actuators via construction of a double network. The obtained fabric-reinforced LCE exhibited a high Young's modulus (12.3 MPa, 3 times that of LCE) and an actuation strain of 15%. During one actuation cycle, it experienced a retractive stress of 1.21 MPa, accompanied by a maximum work density of 138 kJ/m3. Both the mechanical and actuation properties of the LCE have been improved. This new strategy of combination brought the LCE actuators closer to practical applications.

Solid electrolytes (SEs) are urgently needed as key components of solid-state batteries (SSBs). However, the limited physical contact between the SE and electrode gives rise to interfacial issues, causing interrupted charge transport and significant resistance at the interface. In this study, we propose a co-crystalline SE, Li(GLN)2BF4 (GLN, glutaronitrile), exhibiting a combination of properties not found in conventional ceramics, notably a low melting point of 60 degrees C and its grain-boundary fluidity. These features facilitate intimate interfacial contact without external pressure, thereby enabling liquid-like Li+ conduction for high-performance SSBs. Consequently, this SE exhibits an ionic conductivity of 1.43 x 10-4 S cm-1 at 30 degrees C and a lithium-ion transference number of 0.74. Importantly, it exhibits superior structural stability during electrochemical cycling as evidenced by in-situ wide-angle X-ray scattering. Benefitting from these properties, Li||Li symmetric cells exhibit stable operation for 600 h, while Li||LiFePO4 cells retain 92.3 % of its initial capacity after 400 cycles, all operating at room temperature and under zero externally applied pressure. This work paves new avenues for exploring co-crystalline substances that can concurrently achieve interfacial compatibility and chemical stability, in contrast to ceramic electrolytes.

The adjustment of the organic field-effect transistor (OFET) operation mode is crucial to meet the demands of logic circuits. Solid-solution semiconductors provide an effective strategy to continuously tune optoelectronic properties depending on component ratios. Herein, organic solid-solution semiconductors (F16ZnPc) x (PEN)1-x are achieved by coevaporation. The film morphology and lattice constant can be tuned continuously with varying component ratios due to molecular interactions, which is demonstrated by the changes of peaks and charge transfer. Consequently, the threshold voltage of OFETs based on (F16ZnPc) x (PEN)1-x solid solutions can be adjusted over a wide range, resulting in the operation mode that can be tuned just depending on composition ratios. Moreover, the variation of conductance is demonstrated by planar diodes.

Although quasi-two-dimensional (quasi-2D) perovskites are ideal material platforms for highly efficient linearly polarized electroluminescence owing to their anisotropic crystal structures, so far, there has been no practical implementation of these materials for the demonstration of linearly polarized perovskite light-emitting diodes (LP-PeLEDs). This scarcity is due to difficulty in orientation and phase distribution control of the quasi-2D perovskites while minimizing the defects, all of which are required to manifest aligned transition dipole moments (TDMs). To achieve this multifaceted goal, herein, we introduce a synergistic strategy to quasi-2D perovskites by incorporating both a trimethylolpropane triacrylate anchoring layer and 18-Crown-6 molecular passivator into the film fabrication process. It is found that the interfacial anchoring layer guides the oriented growth of perovskites along the (110) plane, whereas the molecular passivator reduces the number of defects and homogenizes the crystal phase. As a result, a quasi-2D perovskite film with macroscopically aligned TDM that renders high radiative recombination and the degree of linear polarization (DoLP) is constructed. This "coherence-programmed emission layer" demonstrates highly efficient LP-PeLEDs, not only achieving a maximum external quantum efficiency of ∼23.7%, a brightness of ∼36,142 cd/m2, and a DoLP of ∼38%, but also significantly improving the signal-to-interference-and-noise ratio in a multi-cell visible light communication system.

Shanghai HIgh repetitioN rate XFEL and Extreme light facility (SHINE) is a 3 km long advanced X-ray source facility. The main superconducting Linear Accelerator (Linac) of SHINE can increase the electron beam energy up to 8 GeV under superconducting (SC) continuous wave (CW) mode. SHINE Linac is mainly based on the seventy-five 1.3 GHz-cavity cryomodules which are connected in series in 1.4 km and operated at superfluid helium temperature of 2 K. Each cryomodule mainly consists of 8 Superconducting Radio Frequency (SRF) cavities, 8 high power couplers, 8 tuners, one cold Beam Position Monitor (BPM) and one superconducting quadrupole (SCQ) magnet. In order to ensure the cryomodules stable operation at 2 K in the Linac tunnel, all the key elements are required to be tested at cryogenic temperatures before their assembly into the cryomodule. A Multifunction Test Facility (MTF) is designed and fabricated, by referring to the 3-cryogenic circuit design for the cryomodule (2 K, 5 K and 45 K) as well as the compatible consideration for all other cryomodules key elements cryogenic tests. SCQ magnet, as designed to work at liquid helium temperature by conduction-cooling, is thus necessary to be carried out on the performance tests in the MTF. This paper will give a detailed description of the MTF, as well as the cryogenic commissioning and test results for the facility itself. The experimental issues related to cryogenic tests of the SCQ magnets, such as the conduction-cooling performance and the cryogenic stability for current tests, are also discussed.

In order to provide hard X-rays with a 1.5 GeV electron ring, a new superbend-magnet will be used in middle of each standard cell at Wuhan Advanced Light Source (WALS). Design, assembly, and detailed magnetic measurement of the prototype have been finished. The results of magnetic measurement show that central magnetic field reaches 3.67 T in a gap of 14.72 mm, and the range of high field region (>3.5 T) is larger than 40 mm in the longitudinal direction. The uniformity of the magnetic field integrals is below 5 × 10 −4 within the good field region.

上海硬X射线自由电子激光装置（SHINE）的一台磁体长度为4 m、周期长度16 mm、磁气隙为5 mm的超导波荡器样机目前已完成集成和测试。本文针对这种超小间隙的超导波荡器，提出了一种基于双霍尔探头的磁场点测量方法，描述了其测量原理，并对样机做了磁场测量和优化实验。通过分段调节其2 m段超导磁体的激磁电流对磁场进行优化，使该段在100 A激磁电流下的相位误差小于5°满足设计要求。实验结果表明了本文提出的磁场测量和优化方法是有效的。

Formamidinium lead triiodide serves as the optimal light-absorbing layer in single-junction perovskite solar cells. However, achieving operational stability of high-efficiency n-i-p type devices at elevated temperatures remains challenging. In this work, we implemented effective surface modifications on microcrystalline perovskite films. This involved the nucleophilic addition of formamidinium cations and coordination of residual PbI2 with triphenylmethane triisocyanate as well as subsequent polymerization. The in situ growth of a cross-linking network chemically anchored on the perovskite film in this approach effectively reduced trap densities, favorably altered surface work function, suppressing interface charge recombination and thus enhancing cell efficiency. Coupled with a high-melting-point air-doping promoter, we fabricated n-i-p type perovskite solar cells surpassing 25 % efficiency, demonstrating excellent operational stability at 65 °C.

A superconducting undulator (SCU) prototype with a magnet length of 4m is being developed for the SHINE (Shanghai High Repetition Rate XFEL and Extreme Light Facility) project. The period length of the undulator is 16mm, the period number is 250, and the pole gap is 5mm. A point measurement system with three Hall probes will be used to measure the magnetic fields in the gap. The Hall probes fixed on a sledge will experience temperatures of about 4.2K to 50K when they move through the undulator gap. A temperature-dependent calibration system for these hall probes is necessary. The paper introduces the configuration of the cryogenic calibration system, and the result for the sensitivity and nonlinearity of one Hall probe from 2.8K to 300K over a magnetic field range of ±1.9T.

In the quest to enhance the efficiency and durability of n-i-p perovskite solar cells (PSCs), engineering hole-transporting conjugated polymers with well-matched energy levels, exceptional film-forming properties, rapid hole transport, and superior moduli is paramount. Here, we present a novel approach involving the customization of a conjugated polymer, designated as p-DTPF4-EBEH, comprising alternating units of an oxa[5]helicene-based polycyclic heteroaromatic (DTPF4) and 5,5'-(2,5-di(hexyloxy)-1,4-phenylene)bis(3,4-ethylenedioxythiophene) (EBEH), synthesized through palladium-catalyzed direct arylation. Relative to homopolymers p-DTPF4 and p-EBEH, p-DTPF4-EBEH demonstrates a proper HOMO energy level, hole density, and hole mobility, alongside superior film-forming capabilities. Remarkably, compared to the commonly used hole transport material spiro-OMeTAD, p-DTPF4-EBEH not only exhibits superior film-forming property and hole mobility but also offers increased modulus and improved waterproofing. Incorporating p-DTPF4-EBEH as the hole transport material in PSCs results in an average power conversion efficiency of 25.8%, surpassing the 24.3% achieved with spiro-OMeTAD. Importantly, devices utilizing p-DTPF4-EBEH demonstrate enhanced thermal storage stability at 85 °C, along with operational robustness.

Group II-VI semiconductor CdTe is widely used in optoelectronic devices because of its high absorption coefficient and good chemical stability. High-quality CdTe thin films serve as the foundation for high-performance optoelectronic devices. In this work, centimeter-scale CdTe thin films were synthesized via van der Waals heteroepitaxy on mica substrates using vapor phase transport (VTD), and planar structure photodetectors (PDs) were constructed via depositing the Au electrodes on the surface directly or exfoliated buried interface. The results show that the performance of PDs constructed using a CdTe buried interface is much better than those constructed using a CdTe surface under the light irradiation at the wavelengths of 406, 642, and 808 nm, and the switching ratio can reach up to 2 x 104, with a response of 4.4 A/W and a short response time of 1.5 ms. The smooth interface morphology and a large area of flat and dense surfaces are conducive to carrier transport, showing better performance. Furthermore, flexible PDs are constructed via transferring CdTe thin films onto a poly(ethylene terephthalate) (PET) substrate and exhibit excellent flexibility and stability, which can maintain 96.5% original performance with more than 200 times bending at a curvature radius of 5 mm. The research indicates that the high-quality, centimeter-scale CdTe with buried interface fabricated via van der Waals epitaxial growth is a promising potential candidate in high-performance optoelectronic devices.

SXFEL intends to use a frequency beating laser-modulated electron beam scheme to simultaneously generate X-rays and high pulse energy tunable frequency coherent terahertz (THz) radiation, which is generated by an electromagnetic wiggler. The wiggler consists of 16 periods, each with a length of 280 mm, and it has an effective magnetic peak strength of up to 1.75 T. By manipulating the energy of the electron beam and the magnetic field of the wiggler, the radiation frequency can be adjusted within a range of 5 to tens of THz. In addition, the wiggler has the capability to modify the coil combination, thereby altering the period to 560 mm. This adjustment leads to a significant increase in the K value. This, in turn, will further reduce the radiation frequency. The results of the magnetic measurement indicate that the wiggler's magnetic field quality meets the requirements of the physical experiment. The wiggler was installed on the SXFEL SASE undulator line in September 2023. This paper presents an overview of the simulation calculations, mechanical design, magnetic measurement scheme, and the final magnetic measurement results of the wiggler.