基于插入WO3缓冲层并五苯有机场效应晶体管性能的研究

The pentacene-based organic field effect transistor （OFET） with a thin transition metal oxide （WO3） layer between pentacene and metal （AI） source/drain electrodes was fabricated. Compared with conventional OFET with only metal AI source/drain electrodes, the introduction of the WO3 buffer layer leads to the device performance enhancement. The effective field-effect mobility and threshold voltage are improved to 1.90 em2/（V.s） and 13 V, respectively. The performance improvements are attributed to the decrease of the interface energy barrier and the contact resistance. The results indicate that it is an effective approach to improve the OFET performance by using a WO3 buffer layer.     

最高功放效率PAPR抑制评估标准和迭代准则

高峰均功率比一直是掣肘OFDM系统性能的最大障碍。为了更精确地评估峰均比抑制对功放失真的影响,提出了最优CCDF(OCCDF)迭代收敛准则。新准则考虑放大器中每个子载波的失真,限定MER条件下得到尽可能低的放大器输入功率回退(IBO),获得最高功放效率所匹配的OFDM整体信号分布。基于此,在CMMB系统中给出了一种高效的时域削波结合星座图扩展(ACE)的峰均比抑制技术。采用OCCDF迭代峰均比抑制方案实验结果:MER=40 dB条件下,基于ACE峰均比抑制的OFDM系统相比抑制前获得了3.05 dB的功放IBO性能改善。对应到功率放大器的性能改善:功放效率提升了15.74%,总功耗和管耗分别降低了22.2%和40.19%。     

Self-Powered Nanofluidic Pressure Sensor with a Linear Transfer Mechanism

The transfer functions of the widely used pressure sensors do not exhibit the desired linearity, which limits their practicability in many fields, such as the Internet of Things and artificial intelligence. Herein, MXene/cellulose nanofiber composite membrane-based linear nanofluidic pressure sensors are demonstrated. The nanoscale gaps between MXene laminates restrict the movement of electrolyte and realize the selective transport of ions, based on which mechanical signals can be converted into electric energy for self-powering. In particular, the generated voltage and current are directly proportional to the applied pressure. The introduction of high-strength cellulose nanofibers not only expands the detection range of the sensor but also achieves continuous adjustment of the nano-gap between MXene laminates, which optimizes the sensitivity of the device. The feasibility of further optimization through the modulation of surface functional groups, electrolyte concentration, and device assembly method is proposed. This 2D nanofluid pressure sensor provides an important approach to manufacture portable and wearable electronic devices for applications in many fields.     

Dispersion-Enabled Symmetry Switching of Photonic Angular-Momentum Coupling

Photonic spin-orbit interactions describe the interactions between spin angular momentum and orbital angular momentum of photons, which play essential roles in subwavelength optics. However, the influence of frequency dispersion on photonic angular-momentum coupling is rarely studied. Here, by elaborately designing the contribution of the geometric phase and waveguide propagation phase, the dispersion-enabled symmetry switching of photonic angular-momentum coupling is experimentally demonstrated. This notion may induce many exotic phenomena and be found in enormous applications, such as the spin-Hall effect, optical calculation, and wavelength division multiplexing systems. As a proof-of-concept demonstration, two metadevices, a multi-channel vectorial vortex beam generator and a phase-only hologram, are applied to experimentally display optical double convolution, which may offer additional degrees of freedom to accelerate computing and a miniaturization configuration for optical convolution without collimation operation. These results may provide a new opportunity for complex vector optical field manipulation and calculation, optical information coding, light-matter interaction manipulation, and optical communication.     

Electret Molecular Configuration Induced Programmable Photonic Memory for Advanced Logic Operation and Data Encryption

Nonvolatile organic photonic transistor (OPT) memories have attracted widespread attention due to their nondestructive readout, remote controllability, and robust tunability. Developing electrets with similar molecular structures but different memory behaviors and light-responsive features is crucial for light-wavelength-modulated data encryption. However, reported OPT memories have yet to meet this challenge. Here a new electret molecule (“H-PDI”) is developed via reconfiguring the linear perylene diimide molecule (“L-PDI”) to a helical shape. Respectively incorporating H-PDI and L-PDI into the floating gate layer results to H-PDI OPT and L-PDI OPT. Attributing to their remarkably different electronic structures and energy bandgaps, H-PDI OPT and L-PDI OPT preferably respond to 405 and 532 nm light irradiation, respectively. Upon electrical programming, data can be written and stored in both memories with good retention features and a high “1”/“0” state current ratio over 10⁵, though the data can only be erased by light with correct wavelengths, rather than the electrical field. Moreover, data stored in a memory array consisting of both H-PDI OPT and L-PDI OPT can only be read out by correct inputs, and wrong inputs will lead to highly deceptive outputs. This study provides a general design strategy of OPT for advanced data encryption and protection.     

Sub-Nanowires Boost Superior Capacitive Energy Storage Performance of Polymer Composites at High Temperatures

Polymer dielectrics with high breakdown strength (E_b) and high efficiency are urgently demanded in advanced electrical and electronic systems, yet their energy density (U_e) is limited due to low dielectric constant (ε_r) and high loss at elevated temperatures. Conventional inorganic fillers with diameters from nano to micrometers can only increase ε_r at the cost of compromised E_b and U_e due to their poor compatibility with polymer matrix. Herein, hydroxyapatite (HAP) sub-nanowires with a diameter of ≈0.9 nm are incorporated in polyetherimide (PEI) matrix to form HAP/PEI sub-nanocomposites. ε_r and E_b of the composites are concomitantly enhanced with only 0.5 wt.% of HAP sub-nanowires, leading to high U_e of 5.14 (@150 °C) and 3.1 J cm⁻³ (@200 °C) with efficiency of 90% and high-temperature stability up to 3 × 10⁵ charge-discharge cycles at 200 °C. Microstructural analysis and molecular dynamics simulations indicate that the sub-nanowires with comparable diameter as polymer chains induce enormous interfacial area, substantially increase mobility of polymer chains and form dense traps for charge carriers. This work extends the current research scope of polymer-inorganics composite dielectrics to the sub-nano-level incorporation and provides a novel strategy for fabricating high performance polymer dielectrics at elevated temperatures.     

A Metal-Free Mesoporous Carbon Dots/Silica Hybrid Type I Photosensitizer with Enzyme-Activity for Synergistic Treatment of Hypoxic Tumor

As a less O₂-dependent photodynamic therapy (PDT), type I PDT is an effective approach to overcome the hypoxia-induced low efficiency against solid tumors. However, the commonly used metal-involved agents suffer from the long-term biosafety concern. Herein, a metal-free type I photosensitizer, N-doped carbon dots/mesoporous silica nanoparticles (NCDs/MSN, ≈40 nm) nanohybrid with peroxidase (POD)-like activity for synergistic PDT and enzyme-activity treatment, is developed on gram scale via a facile one-pot strategy through mixing carbon source and silica precursor with the assistance of template. Benefiting from the narrow bandgap (1.92 eV) and good charge separation capacity of NCDs/MSN, upon 640 nm light irradiation, the excited electrons in the conduction band can effectively generate O₂^•− by reduction of dissolved O₂ via a one-electron transfer process even under hypoxic conditions, inducing apoptosis of tumor cells. Moreover, the photoinduced O₂^•− can partially transform into more toxic ^•OH through a two-electron reduction. Moreover, the POD-like activity of NCDs/MSN can catalyze the endogenous H₂O₂ to ^•OH in the tumor microenvironment, further synergistically ablating 4T1 tumor cells. Therefore, a mass production way to synthesize a novel metal-free type I photosensitizer with enzyme-mimic activity for synergistic treatment of hypoxic tumors is provided, which exhibits promising clinical translation prospects.     

Intrinsically Flexible and Aging Resistant Fluorene-Based Rod-Coil Copolymer for Bendable Deep-Blue PLEDs

In the field of flexible light-emitting display, goal-oriented intelligent molecular design is used to control various behaviors of molecules, which provides potential for the development of flexible light-emitting conjugated polymers (LCPs). The introduction of non-conjugated units into polymer molecules is a key prerequisite for realizing the intrinsic flexibility, but its easy interchain slip will also lead to the formation of interchain excited states, which is detrimental to the efficiency of light-emitting diodes. Herein, two kinds of fluorene-based rod-coil copolymer with stable deep blue emission characteristics is presented and with Commission Internationale de L'Eclairage (CIE) coordinates of (0.18, 0.14) and (0.15, 0.09), respectively. Surprisingly, the copolymer films show efficient blue emission even at 100% tension. Meanwhile, the rod-coil copolymer possesses better aging resistance compared to rigid π-conjugated counterparts. Finally, both rigid and flexible light-emitting diodes based on rod-coil copolymer exhibit stable deep blue emission, and the G2-based PLED with CIE coordinates of (0.16, 0.08), which approach National Television System Committee standard blue specification. These results confirm the validity of rod-coil copolymer design strategy in constructing inherently flexible polymers with deep blue emission, which have great application potential in flexible PLEDs.     

Durable Integrated K-Metal Anode with Enhanced Mass Transport through Potassiphilic Porous Interconnected Mediator

K-metal batteries have become one of the promising candidates for the large-scale energy storage owing to the virtually inexhaustible and widely potassium resources. The uneven K⁺ deposition and dendrite growth on the anode causes the batteries prematurely failure to limit the further application. An integrated K-metal anode is constructed by cold-rolling K metal with a potassiphilic porous interconnected mediator. Based on the experimental results and theoretical calculations, it demonstrates that the potassiphilic porous interconnected mediator boosts the mass transportation of K-metal anode by the K affinity enhancement, which decreases the concentration polarization and makes a dendrite-free K-metal anode interface. The interconnected porous structure mitigates the internal stress generated during repetitive deposition/stripping, enabling minimized the generation of electrode collapse. As a result, a durable K-metal anode with excellent cycling ability of exceed 1, 000 h at 1 mA cm⁻²/1 mAh cm⁻² and lower polarization voltage in carbonate electrolyte is obtained. This proposed integrated anode with fast K⁺ kinetics fabricated by a repeated cold rolling and folding process provides a new avenue for constructing a high-performance dendrites-free anode for K-metal batteries.     

一种L~E波段的A型上电极MEMS单刀三掷开关设计

针对单刀多掷开关(SPMT)在相控阵雷达、宽带收发器中用于切换滤波器和传输线时需要满足宽频带、高隔离度的性能需求,设计了一种宽频带、高隔离度的MEMS单刀三掷开关(SP3T)。通过ANSYS电磁仿真软件中的HFSS模块对MEMS SP3T开关进行优化,利用COMSOL软件对上电极的机械性能进行仿真。仿真结果表明,所设计的MEMS SP3T开关可工作在1~90 GHz的频带内,且插入损耗小于1 dB@90 GHz,隔离度大于35 dB@90 GHz,其整体体积约为0.75 mm³。