Perovskite can be used to prepare high-performance photodetectors due to its excellent optical properties. However, the detection range of perovskite photodetectors is mostly limited to the visible light range, restricting their further development and application. In recent years, combining perovskite with organic bulk heterojunctions to prepare photodetectors with broadband detection capability has proven to be an effective strategy. Through this approach, the response spectrum of the photodetector can be flexibly regulated, and organic compounds can improve the perovskite film quality by passivating defects and inhibit the penetration of water molecules in the air, thereby improving the device performance and stability. In this work, we propose and demonstrate the feasibility of combining MAPbI₃ perovskite with PTB7-Th:COTIC-4F to prepare high-performance photodetectors with wide spectral response characteristics. With the assistance of an organic bulk heterojunction, the defects of perovskite crystals are effectively passivated, and the detection spectrum of the device is successfully extended to about 1100 nm. As a result, the responsivity achieved is 0.58 A/W, 1.19 A/W, and 1.41 A/W under laser illumination of 532 nm, 808 nm, and 980 nm, with the power density of 5 μW/cm² at the bias voltage of −0.5 V, respectively, which is one of the best performances among vertical device structures of this type. Moreover, the stability of the final hybrid film has been greatly improved. This work provides a new approach to the preparation of high-performance and broadband perovskite photodetectors.

Sn-Pb perovskite solar cells, which have the advantages of low toxicity and a simple preparation process, have witnessed rapid development in recent years, with the power conversion efficiency for single-junction solar cells exceeding 23%. Nevertheless, the problems of poor crystalline quality of Sn-Pb perovskite films arising from rapid crystallization rate and facile oxidation of Sn²⁺ to Sn⁴⁺ have become key issues for the further development of Sn-Pb perovskite solar cells. Herein, we report the incorporation of triazinamide (N-(6-methyl-3-oxo-2,5-dihydro-1,2,4-Triazin-4(3H)-YL) acetamide) as an additive to regulate the crystalline growth of Sn-Pb perovskite films, resulting in films with low trap density and large grain size. The triazinamide additive effectively passivated defects in the perovskite films. As a result, the triazinamide-modified perovskite solar cells achieved a higher efficiency of 15.73%, compared with 13.32% for the control device, significantly improving device performance. Notably, the optimal triazinamide-modified perovskite solar cell maintained 72% of its initial power conversion efficiency after being stored in an air environment for nearly 300 h, while only 18% of the power conversion efficiency of the control perovskite solar cell was retained. This study proposes an effective strategy for fabricating highly efficient and stable Sn-Pb perovskite solar cells.

The steam generator (SG) as a key piece of equipment in nuclear power plant servers for both primary and secondary systems. SG tube rupture (SGTR) events occasionally occur during pressurized water reactor operation and cannot be completely avoided. However, traditional leak monitors (such as the N-16 method) are not sensitive to small leak rate changes, and hence cannot be used for low-level leak rate detection under incipient fault conditions and are limited to post-accident analysis of significant releases. In this study, the utilization of Ti₃C₂T_x MXene for monitoring the micro rupture phenomenon of water vapor escaping from U-shaped tubes in a SG is reported for the first time. The experimental results demonstrate that the TiO₂@Ti₃C₂T_x, after undergoing partial oxidation for 2 hours, has a significantly enhanced gas sensing capability towards water vapor in an argon environment between 100 and 300 °C. In addition, its water vapor response time at as low as 100 ppm at 300 °C is less than 3 seconds and has excellent repeatability. The layered Ti₃C₂T_x MXene is beneficial for the adsorption and diffusion of water molecules, making it an excellent platform for conductive transport and carrier collection. TiO₂ nanoparticles formed by partial oxidation provide numerous gas adsorption sites, and the interlayer insertion of water molecules facilitates the interaction between water vapor and charged –OH groups in MXene. This behavior leads to a decrease in the dielectric constant and an increased electrical resistance due to an increased activation energy for electrons/holes transitioning to a free state. TiO₂@Ti₃C₂T_x nanosheets exhibit promising potential for trace water vapor detection and high-temperature environment sensing. Given the low concentration response and high safety, this type of water vapor sensor has great potential for early diagnosis of SGTR accidents.

Metamaterial absorbers in terahertz (THz) based bands have garnered significant attention for their potential applications in military stealth, terahertz imaging, and other fields. Nevertheless, the limited bandwidth, low absorption rate, and heavy weight greatly reduce the further development and wide application of terahertz absorbers. To solve these problems, we propose a polystyrene (PS)-based ultra-broadband metamaterial absorber integrated with a polyethylene terephthalate (PET) double-sided adhesive layer and a patterned indium tin oxide (ITO) film through the simulation method, which operates in the THz band. The electromagnetic wave absorption properties and underlying physical absorption mechanisms of the proposed metamaterial absorbers are comprehensively modeled and rigorously numerically simulated. The research demonstrates the metamaterial absorber can achieve absorption performance of over 90% for fully polarized incident waves in the ultra-wideband range of 1.2–10 THz, especially achieving perfect absorption characteristics of over 99.9% near 1.8–1.9 THz and 5.8–6.2 THz. The proposed absorber has a lightweight physical property of 0.7 kg/m² and polarization-insensitive characteristic, and it achieves a broad-angle that allows a range of incidence angles up to 60°. The simulation research results of this article provide theoretical support for the design of terahertz absorbers with ultra-wideband absorption characteristics.

Perovskite materials have garnered significant attention in both fundamental research and practical applications owing to their exceptional light absorption coefficients, low fabrication costs, and inherent advantages for thin-film and flexible device fabrication. Nevertheless, interface defects within perovskite films induce detrimental non-radiative carrier recombination and pronounced hysteresis effects, which collectively impose substantial limitations on the photovoltaic performance and long-term operational stability of perovskite solar cells (PSCs). Conventional passivation strategies, despite their demonstrated efficacy in mitigating interface defects, often inadvertently introduce secondary defects in originally defect-free regions, thereby restricting the extent of device performance improvement. To overcome this critical limitation, we have developed a precision defect passivation methodology that employs a targeted two-step immersion–cleaning process, achieving selective defect passivation while concomitantly eliminating residual passivating agents. This approach effectively prevents the formation of new defects in unaffected regions of the perovskite films, and the resultant PSC possesses a power conversion efficiency (PCE) of 21.08%, accompanied by a substantial mitigation of hysteresis behavior. Furthermore, unencapsulated devices demonstrate remarkable stability, retaining over 81% of their initial efficiency after 20 days of atmospheric storage under 50% relative humidity, which underscores the effectiveness of our passivation strategy in simultaneously enhancing both device performance and operational stability.

Developing perovskite solar cells (PSCs) with both high performance and long-term stability remains a critical challenge and research focus in the field of photovoltaic devices. Herein, we report a multi-step spin-coating strategy for high-efficiency 2D/3D perovskite heterojunction solar cells by sequentially depositing low-concentration 3-pyridine methylamine iodine solutions onto 3D perovskite films. This approach enables controlled Ostwald ripening and forms graded 2D/3D heterointerfaces rather than insulating capping layers, yielding a champion device with a PCE of 22.7%, significantly outperforming conventional 2D/3D planar counterparts. The optimized structure exhibits enhanced carrier extraction, suppressed recombination, and exceptional humidity stability; the hydrophobic structure further enabled >85% initial efficiency retention after 800 h at 45% relative humidity (RH) for target devices. This study establishes a novel research paradigm for developing high-performance and stable 2D/3D perovskite solar cells through gradient dimensionality engineering.