Science China Materials最新文献

Using a highly sensitive flexible sensor for monitoring the rapidly fluctuating thermal environments of underwater hot springs is a highly promising temperature measurement technology. Herein, a flexible high-temperature sensor was designed, using conductive ITO and sensitive In₂O₃ as the sensing layers. These materials were deposited on a polyimide film substrate and encapsulated with PET material to enable in situ temperature monitoring of rapidly changing thermal environments in underwater hot springs. Simulation results showed that the device achieved a sensitivity of 179.6 µV/°C during rapid cooling from various temperatures to 25 °C without applied pressure, and exhibited a maximum output variation of 5.76% under the same cooling conditions under 20 MPa, reflecting excellent thermal response stability. Furthermore, combined simulation and experimental results indicated that the serpentine electrode structure in the sensor effectively reduced internal stress, enabling it to maintain stable output after 10,000 mechanical bending cycles, thereby demonstrating excellent structural stability and repeatability. Further tests showed that the device maintained stable thermoelectric output over a wide temperature range of 30–300 °C and exhibited excellent performance in various media, including air (flame heating), water, seawater, and high-temperature silicone oil. Notably, after continuous operation in seawater for 20 h and immersion for 48 h, the average variation in the thermoelectric output curve was only 1.94%, demonstrating good corrosion resistance and long-term stability. These characteristics indicate that significant potential is possessed by the flexible sensor for temperature monitoring applications in the extreme thermal environments of underwater hot springs.

In recent years, covalent organic frameworks (COFs) have been rapidly developed due to their advantages, including high specific surface area, stable pores, and stable chemical structures. This has led many researchers to recognize the significant potential of COFs in catalysis, adsorption, and energy storage. The functionality of COFs can be precisely designed through approaches such as modifying building monomers and post-synthetic modification, thus expanding the possibilities for materials development. Topological structures significantly impact the photocatalytic performance, influencing light absorption, photoelectron transfer, and charge carrier migration. Previous studies have underscored the significance of topological structures in COFs-based photocatalysis; however, a comprehensive review remains lacking. To this end, this review focuses on revealing the structure-activity relationship between topological structures and COFs-based photocatalysis, based on an analysis of the photocatalytic mechanism and enhancement mechanisms of topological COFs. In particular, this review systematically elaborates on advances in enhancing photocatalysis of one-dimensional (1D), 2D, and 3D topological COFs. Moreover, the design and modification strategies of topological COFs, including pre-synthesis and post-synthesis regulation strategies, have also been carefully summarized to further enhance their photocatalytic performance. It is anticipated that this review can provide important references and guidance to achieve the efficient development of topological structures in the field of COF photocatalysis.

Quantum dot (QD)-based memristors enable precise and energy-efficient neuromorphic computing through atomic-level control over electrical synapse performance. However, the stochastic nature of QD structures results in the poor reliability of resistive switching in neuromorphic computing, limiting its practical applications. Here, we present a data-driven QD synthesis optimization loop to precisely engineer QD structures for reliable neuromorphic computing. By deeply integrating high-throughput density functional theory with machine learning, we establish a cross-scale screening platform for precise synthesis of QDs, enabling multi-dimension predictions from atomic-level structures to macroscopic electrical synaptic behaviors. Through the minimization of structural disorder, achieved by pure phase, uniform size distribution, and highly preferred orientation, QD-based memristors demonstrate a 57% reduction in switching voltage, a two-order-of-magnitude increase in the ON/OFF ratio, and endurance and retention degradation as low as 0.1% over 8.4 × 10⁷ s of continuous operation and 10⁵ rapid read cycles. Furthermore, the dynamic learning range and neuromorphic computing accuracy are improved by 477% and 27.8% (reaching 92.23%), respectively. These findings establish a scalable, data-driven strategy for rational design of QD-based memristors, advancing the development of next-generation reliable neuromorphic computing systems.

High-performance solar-blind ultraviolet (SBUV) and X-ray detectors are essential for scientific research, medical diagnostics, and astronomical imaging. Ga₂O₃ has emerged as a promising material for detection in this spectral range. However, the distinct mechanisms underlying SBUV and X-ray detection in Ga₂O₃ remain poorly understood, hindering the optimization of device performance. This study introduces oxygen vacancy modulation to explore these mechanistic differences and enhance comprehensive detection capabilities of Ga₂O₃ detectors. Highly crystalline β-Ga₂O₃ films with different oxygen contents were prepared by metal-organic chemical vapor deposition at various oxygen and trimethylgallium (TEGa) precursor ratios (F_oxy/F_TEGa), and corresponding detectors were then fabricated. As the F_oxy/F_TEGa increases, β-Ga₂O₃ crystal quality improves and oxygen vacancy content decreases. The device based on the film with the lowest oxygen vacancy content exhibits a remarkably low dark current of 30.9 fA. Under SBUV (254 nm), the device demonstrates the photo-to-dark current ratio of 8.7 × 10⁸ and a responsivity of 237 A W⁻¹. Notably, the detector achieves a sensitivity of 10,736 µC cm⁻² Gy_air⁻¹ under X-rays, which is 477 times higher than that of conventional a-Se detectors. Additionally, the study clarifies the differential roles of oxygen vacancies in the photoresponse under SBUV and X-ray irradiation, offering insights into how these differences affect both responsivity and response speed. These findings not only deepen the understanding of the SBUV and X-ray photoresponse mechanisms in Ga₂O₃ detectors, but also provide a stepping stone for the design of detectors with excellent comprehensive performance.

Organic light-emitting diodes (OLEDs) have garnered significant attention for their potential in next-generation display technologies, necessitating the development of emitters that combine high efficiency with superior color purity. In this work, an effective approach by integrating spiro-locking motifs and peripheral substitutions is implanted into multiple resonance (MR) frameworks. The rigid and bulky spiro-locking unit suppresses the vibrations and mitigates aggregation tendencies, preserving the narrow full width at half-maximum (FWHM) in doped films. Peripheral substitutions provide a fine tuning of emission to pure green region. This structural design also facilitates a high horizontal dipole ratio, leading to external quantum efficiencies (EQEs) of 29.5% for LL108 and 24.4% for LL125, with FWHMs less than 30 nm. These devices achieved Commission Internationale de l’Éclairage coordinates of (0.20, 0.71) and (0.18, 0.72) for LL108 and LL125, respectively, closely aligning with the BT.2020 standard for green emission. Sensitized OLEDs exhibit enhanced electroluminescent performance, achieving a maximum EQE of 30.3% and significantly reduced efficiency roll-off. Although a slight decrease in color purity is observed, optimization through the selection of more compatible sensitizers is feasible. Our study underscores the potential of spiro-locking designs in developing efficient, high color-purity green emitters, contributing to the advancement of OLEDs for ultrahigh-definition displays.

Iron-based mixed phosphates are considered as promising cathode materials for sodium-ion batteries (SIBs) due to their low cost, non-toxicity, and high structural stability. However, their electrochemical performance is limited by poor electronic conductivity and sluggish ion diffusion. In this study, Na₄Fe₃(PO₄)₂(P₂O₇) with porous coral-like S-doped carbon (NFPP-U0.5%) is presented as cathode materials for SIBs. The porous coral-like structure of the S-doped carbon layer, along with the C–S–Fe interaction, significantly enhances both electronic conductivity and sodium ion diffusion. NFPP-U0.5% delivers excellent rate performance, achieving a capacity of 80.3 mAh g⁻¹ at 20 C. Moreover, the in-situ X-ray diffraction analysis reveals that the C–S–Fe interaction, combined with the unique carbon structure, contributes to a small lattice volume change during cycling. NFPP-U0.5% finally reached an ultra-long cycling life (capacity retention of 82.66% after 25,000 cycles at 20 C). The outstanding electrochemical performances and the unique interface interaction demonstrate that the S-doped carbon coating NFPP is of high potential as a cathode material for low cost and long-lasting cyclability energy storage system.