Current Applied Physics最新文献

High-performance transparent quantum-dot light-emitting diodes (TQLEDs) are achieved through fine-tuning the top dielectric/metal/dielectric (DMD) anode structure. The transparent DMD electrodes are utilized as both the bottom cathode and top anode of TQLEDs. Employing WO_x/Ag/WO_x DMD anodes serves a dual purpose of transparency and hole injection, thereby streamlining the TQLED design. Investigation into the effects of the thicknesses of WO_x and Ag layers on the device characteristics reveals an optimal configuration of 10-nm WO_x/27-nm Ag/40-nm WO_x for the DMD anode. The resulting TQLED exhibits a remarkable device light transmittance of 47 % at 530 nm. With maximum bottom and top emission current efficiencies of 34.0 and 9.42 cd/A, respectively, the total emission obtained by summing the bottom and top emissions reaches the maximum current efficiency of 41.8 cd/A, surpassing that of conventional opaque quantum-dot light-emitting diodes. This advancement underscores the successful fabrication of TQLEDs boasting higher efficiency alongside substantial light transmittance.

Developing feasible Ag nanowire (NW) transparent conductive thin films (TCFs) with good conductivity, transparency, mechanical durability, strong adhesion, and high stability is a great challenge. Herein, novel TCFs composed of Ag NWs/Al₂O₃ on polyethylene terephthalate (PET) substrates with synchronously improved conductivity, transparency, mechanical durability, adhesion, and stability, are prepared. The corresponding values (before coating Al₂O₃: 13.0 Ω/sq. at 86.1 %, after coating Al₂O₃: 11.7 Ω/sq. at 87.7 %) indicate that the deposition of Al₂O₃ enhances the transparency and conductivity of Ag NW networks. Moreover, the resistance does not change significantly after 50 taping cycles and 2000 bending cycles with a bending radius of 5.0 mm, indicating the strong adhesion and good mechanical flexibility of Al₂O₃/Ag NWs composites. In addition, Al₂O₃/Ag NWs composites possess excellent stability to resist strong oxidizing, hot and humid environments. As a proof of concept, the flexible transparent heater prepared by Al₂O₃/Ag NWs composites is successfully demonstrated, verifying the practicability.

Solution-processable perovskite solar cells (PSCs) have the potential to revolutionize solar cell technology by enabling low power generation costs via low-cost device fabrication. However, most existing research regarding PSCs relies on the spin-coating method, which is not conducive to large-area film deposition. Therefore, the development of an alternative deposition method for perovskite films has become increasingly important for commercialization, for which electrospray deposition is a promising technique. This study investigates the two-step preparation of methylammonium lead triiodide (MAPbI₃) perovskite films via the electrospray deposition of a methylammonium iodide (MAI) solution on a spin-coated PbI₂ film. The gradual conversion of PbI₂ to MAPbI₃ with increasing MAI deposition time was revealed, accompanied by an increase in the size of the perovskite crystals. In addition, PSCs were successfully fabricated by electrospraying MAI, achieving a considerable power conversion efficiency of 7.86 % at the optimal MAI deposition time.

The accuracy of modern scientific research and technological advancement is highly reliant on the ability to accurately measure weak signals. The lock-in amplifier (LIA) represents an indispensable instrument, skillfully extracting these faint signals from a backdrop of noise. As the pursuit of accuracy intensifies, LIA technology has been continuously adapted and optimized. This review offers a comprehensive analysis of the evolution and applications of LIAs in weak signal measurements. It presents a structured introduction to the historical development of LIAs and evaluates their diverse applications across various domains, including impedance, optical, electrochemical, thermal, and biosensing methods. By examining specific examples in each field, it showcases the significant impact of LIAs on enhancing measurement precision. The review concludes by highlighting persistent challenges encountered by LIAs in practical settings and explores potential avenues for their future advancement. Future research aims to address practical challenges, including further noise reduction, improved system stability, and ease of use, ensuring LIAs continue to play a pivotal role in scientific and technological progress.

In this study, we developed a simple and facile synthesis method for producing CuS films at low temperatures. The method uses self-reducible complex inks comprising copper formate (Cuf) as the copper source and thioacetamide (TA) as both the sulfur source and complexing agent. The thermal properties of complex inks with different TA/Cuf ratios (0.5–2.0) were analyzed. The ink with a TA/Cuf ratio of 1 exhibited a significant decrease in the reduction temperature. The synthesis of a CuS film involved calcination of the ink at 140 °C; however, some residual Cuf was observed. Introducing hexanol to the ink, aimed at prolonging the liquid-phase reaction, yielded a pure CuS film that contained agglomerated particles. The thermal reduction pathway of Cuf to CuS was analyzed through thermogravimetric–mass spectrometric analysis, and the results revealed that the low-temperature synthesis was attributed to the formation of acetonitrile and formic acid during thermal decomposition of the ink.

First-principles calculations on phonon dynamics using density functional theory (DFT) have proven powerful in estimating the phonon dispersion of crystalline structures. However, it remains a challenging task for defective structures due to the computational cost. The main computational bottleneck of the phonon calculation is obtaining the interatomic force constants in many supercells with different configurations of displacements. Here, we employed a machine learning-based force fields (MLFFs) to accelerate DFT calculations of interatomic force constants of Si-doped HfO₂. We find that the specific phonon band originated from ferroelectric phase disappears, and imaginary modes are enhanced upon the introduction of a 10 % concentration of Si dopants, which is in good agreement with experimental results. This work demonstrates that MLFFs can be a promising application for predicting the phonon dispersion of both crystalline and defective structures.

Spin-coating stands out as one of the fastest and simplest processes for material solidification. While it is commonly employed for producing polycrystalline thin films, recent endeavors have explored its potential for epitaxial growth, albeit primarily limited to inorganic materials. In this study, we demonstrate the spin-coating method enabling the rapid growth of large-sized organic single crystals (OSCs). Within 2 h, we successfully obtained OSCs with controlled lateral sizes of up to 2 mm, which conventionally takes several weeks using slow solvent evaporation. Raman mapping and UV–Vis absorption measurements confirmed the growths of the OSCs. We propose the growth mechanism by using the supersaturated dynamic fluid model. Furthermore, we demonstrate the device integration of these OSCs for charge-transfer complex channel, revealing ambipolar behavior during gate sweep. This innovative OSCs production method has the potential to advance the various field of science and electronics, traditionally hindered by the scarcity of adequately sized OSCs.

Herein, the rotary triboelectric nanogenerator (R-TENG) with a modified structure is simulated and fabricated to investigate the effect of changes on the geometric structure experimentally. The R-TENGs were fabricated using cost-effective and easily accessible dry-film lithography based on the PCB approach. This process which is explained step-by-step in detail in this paper, provides uniform electrode layers without using high-tech instruments, resulting in enhanced fabrication speed and electrical performance. R-TENGs with varying electrode and PTFE sector counts (32/16, 16/8, and 8/4) were fabricated and analyzed. At 1000 rpm, the output power of R-TENGs with 8, 16, and 32 electrodes demonstrated escalating output power with increasing electrode numbers: 6.82, 19.52, and 30.64 Wm^-2, respectively. Simulation results corroborated the experimental findings, confirming that more electrodes and freestanding sectors yield superior power density and electrical generation. The 32-electrode, 16-sector R-TENG outperformed its counterparts, suggesting that strategic design alterations can significantly optimize energy harvesting in R-TENGs.

Ge₂Sb₂Te₅ (GST225) thin films are used as a functional element in multilayer cells of phase change random access memory (PCRAM, PCM) and have good prospects in electrically driven tunable reflective metasurfaces and on-chip waveguide devices, including those implemented on a flexible substrate. Knowledge of the mechanical properties of GST225 thin films, their adhesion to conductive layers, and the correct choice of conductive material is critical to the reliable operation of these devices. The present work focuses on the effect of phase change on mechanical parameters such as hardness, Young's modulus and stiffness, as well as on the adhesion of GST225 thin films to various metal sublayers (Al, Ti, TiN, W, Ni). The formation of GST225 films was carried out by vacuum thermal evaporation and DC magnetron sputtering, which made it possible to study layers with different distributions of elements over the thickness.