Humidity Stability Research Articles

Fluorinated Pyrimidine Bridged Buried Interface for Stable and Efficient Wide‐Bandgap Perovskite Solar Cells

AbstractThe buried interface of wide‐bandgap (WBG) perovskite solar cells (PSCs) is crucial for effective charge transfer and device stability. In this study, 2,4‐diamino‐6‐fluoropyrimidine (DMFP) is incorporated into the perovskite layer to form a molecular bridge at the buried interface between the perovskite and MeO‐4PACZ. DMFP treatment reduces the agglomeration of MeO‐4PACZ, resulting in denser and more uniform self‐assembled monolayers (SAMs) by inducing favorable crystal orientation. In addition, the strong chemical interaction between DMFP and perovskite films significantly reduces defect state density and promotes the growth of high‐quality perovskite grains. Moreover, DMFP treatment effectively modulates the energy levels of perovskites, facilitating interfacial charge extraction. As a result, WBG PSCs treated with DMFP demonstrate a remarkable power conversion efficiency (PCE) of 21.96%, with an enhanced short‐circuit current density (JSC) of 21.60 mA cm−2 and a high open‐circuit voltage (VOC) of 1.23 V. The prepared WBG PSCs retain 95.5% of their initial efficiency after 1500 h of aging at a relative humidity of ≈30% in air, indicating excellent humidity stability. This study contributes to a deeper understanding of the perovskite buried interface and proposes a collaborative approach for developing high‐performance WBG PSCs.

Observed Climatology and Formation Mechanisms of Sea Fog Along the Trans‐Arctic Shipping Routes

AbstractAs Arctic sea ice rapidly melts, trans‐Arctic shipping routes are emerging with significant economic value and potentially reshaping global shipping patterns. The safety of ships navigating along these routes will be severely threatened by low visibility caused by Arctic sea fog. Here, we utilize ship and coastal site observations spanning 1979–2023 to investigate the climatological features and mechanisms of Arctic sea fog from June to September. We find that the Northern Sea Route (NSR, along the Russian coast) experiences a mean fog frequency of 20.0%, significantly higher than the 11.5% fog frequency observed along the Northwest Passage (NWP, along the Canadian coast). Fog frequency shows null correlation with sea ice but a strong negative correlation (−0.80) with surface air temperature. The lower mean surface air temperature in the NSR region enhances relative humidity and atmospheric stability, which are conducive to fog formation and maintenance. We further reveal that fog formation mechanisms differ between the NSR and NWP. Along the NSR, fog is usually advection fog, associated with upper boundary layer warming and moistening; in contrast, along the NWP, fog is typically radiation fog linked to near‐surface cooling. Our study highlights the distinct fog frequency and dominant mechanisms along the different trans‐Arctic shipping routes, thereby establishing observed reference for the model validation of simulating Arctic sea fog.

Electrophilic-Attack Doped Organic Field-Effect Transistors for Ultrasensitive and Selective Hydrogen Sulfide Detection.

Doping of organic semiconductors (OSCs) has been developed as an effective means of modulating the density and transfer efficiency of charge carriers; however, realization of effective doping to tailor the chemical sensing performance of OSC-based sensors still remains not explored extensively. In addition, the application of OSCs in chemical sensors is usually limited by the poor stability and low selectivity. Herein, flexible donor-acceptor copolymer-based organic field-effect transistor (OFET) chemical sensors are designed via an electrophilic attack doping strategy. The p-dopant trityl tetrakis(pentafluorophenyl) borate (TrTPFB) can be effectively doped into the host molecular N-alkyl-diketopyrrolo-pyrroledithienylthieno[3,2-b]thiophene (DPPDTT). It is simple to alter the doping efficiency and film thickness (ca. 5.5-17.7 nm) by adjusting the proportion and concentration of guest-host molecules, which endows facile carrier mobility and enhanced sensing sensitivity modulation toward reducing gases at room temperature. Particularly, 1.0 mol% TrTPFB-doped DPPDTT achieved the highest response to H2S gas, including ultralow detection concentration (0.5 ppb), excellent selectivity, high humidity stability, and long-term storage stability. This work can provide a new strategy for the potential applications of the organic electronic sensing devices.

Enhanced Low-Humidity Performance of Polymer Exchange Membrane Fuel Cells via Membrane Surface Engineering.

Polymer electrolyte membrane fuel cells (PEMFCs) play a pivotal role in meeting the energy needs of high-power applications such as construction and agricultural machinery and mobility. High-power operation often exacerbates problems associated with water management within the cell due to excessive water generation, affecting water distribution at the cathode and anode interfaces. Our research recognizes the importance of addressing challenges associated with the high-power operation of polymer electrolyte membrane fuel cells (PEMFCs) for use in high-power fuel cell applications. The introduction of surface-patterned membranes leads to overall performance enhancement and improved humidity stability, thereby mitigating critical issues related to high-power operation. The enhanced contact at the electrolyte/catalyst interface and the expanded three-phase interface contribute to better heat dissipation and water management, ultimately alleviating challenges associated with catalyst efficiency and water stability during high-power usage. Furthermore, the improved low-humidity performance and stability observed in our study leverage the excessive water generated during PEMFC low-humidity operation. This not only enhances overall performance but also presents an opportunity to improve efficiency by utilizing the excess water generated, potentially reducing the costs associated with humidification maintenance. Our findings highlight the potential of surface-patterned membranes to address both high-power and low-humidity challenges, offering a comprehensive solution for the optimal performance of PEMFCs in demanding applications such as construction and agricultural machinery, as well as in the field of mobility.

6-Trifluoromethylnicotinamide Bilaterally Anchored All Cations Implementing Efficient and Humidity-Stable Perovskite Solar Cells.

For organic-inorganic hybrid perovskite solar cells (PSCs), the volatilization of organic components and the presence of undercoordinated Pb2+ ions are the primary causes of device stability imbalance. These factors also serve as significant determinants that restrict the commercialization scale of PSCs. Here, 6-trifluoromethylnicotinamide (TNA) molecules, featuring amide and trifluoromethyl groups at both ends, were introduced as Lewis additives into the precursor solution of perovskite to anchor all cation defect sites and optimize the crystallization process of perovskite. Theoretical calculations confirmed that the -NH2 and C═O groups within the amide group on one side of the TNA molecule synergistically passivated the undercoordinated Pb2+ ions, whereas the trifluoromethyl group on the other side formed hydrogen bonds with the organic components of perovskite. The scorpion-like bilateral all-cation anchoring ability of TNA molecules was further substantiated through experimental characterization. Upon optimization of the TNA treatment concentration, a perovskite film characterized by large grains and a reduced defect density of states was achieved. The photovoltaic performance of PSCs incorporating TNA exhibited significant enhancement with an increase in efficiency from 22.42% (Control) to 24.15%. Under a harsh high-humidity environment, the comprehensive cation passivation effect of TNA significantly hindered the decomposition and phase transition of perovskite films, thereby ensuring excellent humidity stability for the PSCs.

Optimizing Hygroscopic Metal–Organic Frameworks via EDTA‐Mediated Structural Reinforcement and Photothermal Modification

AbstractHygroscopic metal–organic frameworks (MOFs) are considered as superior moisture sorbents due to their highly adjustable and desired water adsorption/release performance, enabling effective atmospheric water harvesting (AWH) in arid regions. However, the water adsorption capacity, recycling stability, and functionality of current MOFs should be further improved to meet the requirements of practical AWH systems. Here the hydrophilicity at low relative humidity (RH) and cycling stability of MOF‐808 are simultaneously enhanced through the ethylenediaminetetraacetic acid (EDTA)‐mediated post‐modification. Based on the structural reinforcement, EDTA‐modified MOF‐808 (E‐MOF‐808) delivers a stable water uptake capacity of 0.39 g g−1 at 25% RH even after 50 water adsorption–desorption cycles, more than five times that of pristine MOF‐808. In addition, bridging by EDTA with the strong chelating ability, the E‐MOF‐808 can spontaneously capture Cu2+ for further functional improvement. Accordingly, light‐absorbing CuS nanoparticles can be in situ decorated on E‐MOF‐808 for facilitating solar‐driven water release. It is envisioned that this EDTA‐mediated function enhancement should provide valuable insights into the all‐in‐one design of versatile MOFs sorbents.

Design and characterization of a new quartz smog chamber system for studying the atmospheric effects of vehicle emissions on plateaus

Since the 1960s, smog chambers have been an important tool for studying air pollution, and many indoor and outdoor smog chambers have been developed both domestically and internationally. However, all of these chambers are located at altitudes below 1500 m, only simulating atmospheric conditions in low-altitude plains. Moreover, most are made of polytetrafluoroethylene (PTFE), resulting in a higher wall deposition effect. To simulate the evolution of atmospheric pollution in high-altitude regions, we developed the world's highest-altitude quartz smog chamber, located in Kunming at an elevation of 1900 m. The chamber is a 3.375m³ cube constructed from 5 mm quartz glass and features controlled temperature (0 °C–40 °C) and relative humidity (2%–95%). We conducted a comprehensive characterization of the chamber, including tests for temperature and humidity stability, mixing stability, pressure resistance and sealing, light intensity measurement and environmental light matching, and background pollutant and wall loss assessments. The characterization results indicate excellent performance in simulating sunlight and controlling background pollutants. The NO2 photolysis rate is adjustable, ranging from 2.03 × 10⁻³s⁻1 to 5.87 × 10⁻³s⁻1. Under dry conditions, after 6 h of photooxidation, the detected O3 formation rate was approximately 1.05 ppb/h, with a particulate mass concentration around 0.12 μg/m³. The reactor withstands pressures exceeding 1.5 bar, and at this pressure, the leak rate was measured at 1.1‰. Validation using the toluene-NO₂ system showed that indoor mixing reached equilibrium in about 4 min. The wall loss rate for SWFU-HAP particles at 25 °C and RH <10% was 0.066 h⁻1, which is 70% lower compared to other chambers, while at RH = 50%, the wall loss rate was 0.137 h⁻1. These results demonstrate the superior performance of our system, meeting the high standards required for high-altitude vehicle exhaust aerosol emissions research and the investigation of the formation mechanisms of vehicle exhaust in high-altitude atmospheric environments.

Vacancy Effect on the Luminescent and Water Responsive Properties of Vacancy-Ordered Double Perovskite Derivatives.

Vacancy-ordered perovskites and derivatives represent an important subclass of hybrid metal halides with promise in applications including light emitting devices and photovoltaics. Understanding the vacancy-property relationship is crucial for designing related task-specific materials, yet research in this field remains sporadic. For the first time, we use the Connolly surface to quantitatively calculate the volume of vacancy (V□, □=vacancy) in vacancy-ordered double perovskite derivatives (VDPDs). A relationship between void fraction and the structure, photoluminescent properties and humidity stability was established based on zero-dimensional (0-D) [N(alkyl)4]2Sb□Cl5□'-type VDPDs. Compared with the more commonly studied A2M(IV)X6□-type double perovskite (A=cation, M=metal ion, X=halide), [N(alkyl)4]2Sb□Cl5□' features double vacancy sites. Our results demonstrate an inverse relationship between the photoluminescent quantum yield and V□ in 0-D VDPDs. Additionally, structural transformation from A2SbCl5 to A3Sb2Cl9 was first reported, during which the novel 'gate-opening' gas adsorption phenomenon was observed in VDPDs for the first time, as evidenced by 'S'-shaped sorption isotherms for water vapor, indicating a cation-controlled water-vapor response behavior. A mixed-cation strategy was developed to modulate the humidity stability of VDPDs. Characterized by controllable water-responsive behavior and unique 'on-off-on' luminescent switching, A2M(III)□X5□'-type materials show great promise for multi-level information anti-counterfeiting applications.

Vacancy Effect on the Luminescent and Water Responsive Properties of Vacancy‐Ordered Double Perovskite Derivatives

AbstractVacancy‐ordered perovskites and derivatives represent an important subclass of hybrid metal halides with promise in applications including light emitting devices and photovoltaics. Understanding the vacancy‐property relationship is crucial for designing related task‐specific materials, yet research in this field remains sporadic. For the first time, we use the Connolly surface to quantitatively calculate the volume of vacancy (V□, □=vacancy) in vacancy‐ordered double perovskite derivatives (VDPDs). A relationship between void fraction and the structure, photoluminescent properties and humidity stability was established based on zero‐dimensional (0‐D) [N(alkyl)4]2Sb□Cl5□′‐type VDPDs. Compared with the more commonly studied A2M(IV)X6□‐type double perovskite (A=cation, M=metal ion, X=halide), [N(alkyl)4]2Sb□Cl5□′ features double vacancy sites. Our results demonstrate an inverse relationship between the photoluminescent quantum yield and V□ in 0‐D VDPDs. Additionally, structural transformation from A2SbCl5 to A3Sb2Cl9 was first reported, during which the novel ‘gate‐opening’ gas adsorption phenomenon was observed in VDPDs for the first time, as evidenced by ‘S’‐shaped sorption isotherms for water vapor, indicating a cation‐controlled water‐vapor response behavior. A mixed‐cation strategy was developed to modulate the humidity stability of VDPDs. Characterized by controllable water‐responsive behavior and unique ‘on‐off‐on’ luminescent switching, A2M(III)□X5□′‐type materials show great promise for multi‐level information anti‐counterfeiting applications.

Iodide Management and Oriented Crystallization Modulation for High-Performance All-Air Processed Perovskite Solar Cells.

Halide-related defects at the buried interface not only cause nonradiative recombination, but also seriously impair the long-term stability of perovskite solar cells (PSCs). Herein, a bottom-up, all-in-one modification strategy is proposed by introducing a multisite antioxidant ergothioneine (EGT) at the buried interface to manage iodide ions and manipulate crystallization dynamics. The findings demonstrate that EGT not only passivates uncoordinated Sn4+/Pb2+ defects, but also firmly anchors iodide ions and inhibits their oxidation to I2. Additionally, the modification by EGT enhances the oriented crystallization of perovskite, improves the carrier dynamics, and releases residual stresses. Consequently, the optimized all-air processed device (Rb0.02(FA0.95Cs0.05)0.98PbI2.91Br0.03Cl0.06) achieves a remarkable power conversion efficiency (PCE) of 25.13%, which is among the highest values reported for devices fabricated in air, along with ultrahigh open-circuit voltage (VOC) of 1.191V and fill factor (FF) of 84.9%. The optimized device without encapsulation exhibits strong humidity, thermal, and operational stability under ISOS protocol. Specifically, the initial efficiency of the device is retained at 90.12% after 1512 h of thermal ageing at 65°C and 90.14% after 930 h of continuous maximum power point tracking (MPPT) under simulated AM1.5 illumination.

Ultra-compact dual-channel integrated CO2 infrared gas sensor

Expiratory CO2 concentrations can directly reflect human physiological conditions, and their detection is highly important in the treatment and rehabilitation of critically ill patients. Existing respiratory gas analyzers suffer from large sizes and high power consumption due to the limitations of the internal CO2 sensors, which prevent them from being wearable to track active people. The internal and external interference and sensitivity limitations must be overcome to realize wearable respiratory monitoring applications for CO2 sensors. In this work, an ultra-compact CO2 sensor was developed by integrating a microelectromechanical system emitter and thermopile detectors with an optical gas chamber; the power consumption of the light source and ambient temperature of the thermally sensitive devices were reduced by heat transfer control; the time to reach stabilization of the sensor was shortened; the humidity resistance of the sensor was improved by a dual-channel design; the light loss of the sensor was compensated by improving the optical coupling efficiency, which was combined with the amplitude trimming network to equivalently improve the sensitivity of the sensor. The minimum size of the developed sensor was 12 mm × 6 mm × 4 mm, and the reading error was <4% of the reading from −20 °C to 50 °C. The minimum power consumption of the sensor was ~33 mW, and the response time and recovery time were 10 s (@1 Hz), and the sensor had good humidity resistance, stability, and repeatability. These results indicate that the CO2 sensor developed using this strategy has great potential for wearable respiratory monitoring applications.

Post-Treating Grain Boundaries and Surface Defects by Long-Chain Polymer for Highly Efficient and Stable Perovskite Solar Cells.

Grain boundaries (GBs) and surface defects within perovskite films are inherent challenges that affect the photovoltaic performance of perovskite solar cells (PSCs. In this work, Nylon 11 (N11) is utilized, a long-chain polymer, for post-treating the GBs and surface defects within FAPbI3 films. The multifunctional groups of N11 exhibit unique passivation abilities, enabling self-regulation and selective correction of reverse-charged defects. Post-treating with N11 results in high-quality FAPbI3 films characterized by tight GBs and low surface defect density. Despite fabrication under full open-air conditions, the N11 post-treatment significantly enhances the power conversion efficiency (PCE) value of FAPbI3 PSCs, increasing it from the reference value of 21.89% to 23.54%. Importantly, the long alkyl chain present in N11 significantly enhances the humidity stability of the PSCs. Unencapsulated PSCs treated with N11 maintain 89% of their initial PCE after exposure to air with 30% relative humidity (RH) for 1000h, demonstrating resilience to elevated humidity levels. This work highlights the substantial improvement in the photovoltaic performance of PSCs achieved through the post-treatment with N11.

Ultrahigh Electrical Conductivity in p-Type CsPbI2Br Perovskite Thin Films by Modulation Doping.

The widespread adoption of halide perovskites for application in thermoelectric devices, DC power generators, and lasers is hindered by their low charge carrier concentration. In particular, increasing their charge carrier concentration is considered the main challenge to serve as a promising room-temperature thermoelectric material. Efforts have been devoted to enhancing the charge carrier concentration by doping and composition engineering. However, the coupling between charge carrier concentration and mobility, along with the poor stability of these materials, impedes their development for thermoelectric applications. Herein, we demonstrate the successful increase in the charge carrier concentration of CsPbI2Br by forming a heterojunction structure with Cu2S via a facile spin-coating method. The excellent band alignment between two materials combined with a charge-transfer mechanism realizes the modulation doping, resulting in 8 orders of magnitude increase in carrier concentration from 1012 to 1020 cm-3 without detrimental effect on the carrier mobility of CsPbI2Br. The thermoelectric power factor of the heterostructured CsPbI2Br reached 6.6 μW/m·K2, which is 330 times higher than that of pristine CsPbI2Br. Furthermore, these films showed higher humidity stability than the control films. This study offers a promising avenue for increasing the charge carrier concentration of halide perovskites, thereby enhancing their potential for various applications.

Implementation of Sugeno Fuzzy Logic Method as an Automatic Humidity and Moisture Control System in Terrarium

A terrarium is a mini ecosystem that requires precise humidity control to ensure plant growth and the survival of animals within it. However, manual humidity control is difficult to implement consistently, especially if the external environment changes. This problem can be overcome by implementing an automatic system based on Sugeno fuzzy logic. This research aims to design and implement an automatic system that is able to control terrarium humidity dynamically using a fuzzy logic approach. This system is designed using humidity sensor data as input which is then processed through Sugeno fuzzy logic to determine appropriate control actions. The method used involves modeling input humidity and temperature sensors, determining fuzzy rules, and defuzzification using the Sugeno method to regulate the automatic irrigation system in the terrarium. Tests were conducted under several different environmental conditions to measure the system's response to changes in humidity and temperature. The research results show that the system is able to maintain terrarium humidity within optimal limits with a low error rate. The system is able to adjust control actions in real-time, produce consistent calculations, and provide humidity stability despite external changes.

A Sulfide‐Based Solid Electrolyte With High Humid Air Tolerance for Long Lifespan All‐Solid‐State Sodium Batteries

AbstractSulfide‐based superionic conductors present great promise to achieve high energy density and safety for all‐solid‐state sodium batteries (ASSSBs). However, the poor electrolyte/electrode interface compatibility and humid air stability seriously hinder their deployment in ASSSBs. Herein, a series of high‐performance Na3‐□Sb1‐4x(SnWCaTi)xS4 sulfide‐based solid electrolytes (SSEs) are reported by coupling the vacancy effect with configurational entropy, which displays an excellent interface stability against sodium metal and an extraordinary tolerance toward the moist atmosphere, even for water. The optimized electrolyte effectively inhibits the detrimental mixed ion‐electron conducting interphase formation, achieving the ultra‐stable operation of Na–Na symmetric cell up to 1000 h. Furthermore, the Na+ diffusion kinetics is obviously enhanced by increasing the Na sites local anisotropy and Na vacancies. Eventually, the assembled TiS2//Na5Sn ASSSBs deliver a remarkable reversible capacity of 211.6 mAh g−1 at 0.5C with a long‐term cycling performance of 450 cycles at room temperature. More importantly, it achieves a steady running up to 100 cycles at 1C even if this electrolyte is placed in the air with a dew temperature of 13.8 °C for 30 min, the highest values in the state‐of‐the‐art sulfide‐based ASSSBs. The well‐designed SSEs open a new avenue for realizing the advanced and powerful ASSSBs.

Dimeric Carbazole Core Based Dopant‐Free Hole Transport Material for n‐i‐p Planar Perovskite Solar Cell

AbstractA profitable approach for improving the stability of n‐i‐p planar perovskite solar cell (PSC) is developing dopant‐free hole transport materials (HTMs) with desirable intrinsic charge transport properties. In this work, by adopting a metal‐free catalytic intramolecular C─C coupling reaction, a carbazole dimer‐based fused‐ring is synthesized, and further developed a small molecular dopant‐free HTM abbreviated as NCz‐DM with appropriate energy level, excellent hole transport and film formation properties. Applied in n‐i‐p planar PSC, an impressive power conversion efficiency (PCE) of 24.0% is achieved, together with enhanced humidity, thermal and light stability, which is among the high level of ever‐reported results for PSCs utilizing small molecular dopant‐free HTM.

Highly stable wavelength converting composite based on sol–gel derived siloxane-encapsulated luminescent nanocrystals

Luminescent nanocrystals (NCs) have emerged as the high-performance wavelength converting materials in next-generation displays and energy conversion devices due to their unique optophysical properties, such as large Stokes or anti-Stokes shifts, narrow emission bandwidth, and tunable bandgap depending on size or composition. However, poor long-term stability in high temperature and humidity remains a critical issue for device applications. This instability is primarily due to irreversible changes in surface ligands or chemical structures/compositions when exposed to various severe environments. Various strategies have been reported to address these issues, such as the formation of inorganic shell layers and the fabrication of polymer-based nanocomposites. Although these strategies have improved stability, they exhibit degraded properties during long-term aging. Recently, sol–gel derived siloxane hybrid materials have been introduced to achieve stability for various NCs under actual operating conditions of displays and optoelectronic devices. This review will address recent progress in developing siloxane-encapsulated NCs with high stability in high temperature/humidity and under continuous light exposure. It will also introduce results on enhancing the environmental stability of various NCs, including lanthanide-doped transition metal-based NCs, semiconducting NCs, and metal halide perovskite NCs, as well as demonstrations of reliable devices.Graphical

Heterogeneous Nucleation and Enhanced Charge Transfer via Amorphous Metal‐Organic Frameworks for Efficient and Stable Perovskite Solar Cells

AbstractThe two‐step sequential deposition method is considered a potential way for the large‐scale manufacture of perovskite solar cells (PSCs) with high power conversion efficiency and reproducibility. However, the dense lead iodide (PbI2) film interferes with its full contact with organic solutions, resulting in an inadequate reaction at the interface. Herein, 2 kinds of metal‐organic framework (MOF) are introduced, amorphous Ni‐MOF‐74 (amNi‐MOF‐74) and crystalline Zn‐MOF‐74 (crZn‐MOF‐74), into PbI2 for regulating crystallization. Compared to crZn‐MOF‐74, the incorporation of amNi‐MOF‐74 exhibited rapid nucleation, resulting in high‐quality perovskite films with large grain size, low trap density, and enhanced charge transfer between the perovskite and charge transfer layers. Meanwhile, the content of unstable phase PbI2 left in perovskite films due to insufficient reaction is also reduced. The amNi‐MOF‐74 modified PSCs exhibited a champion power conversion efficiency of 24.17% with good humidity and thermal stability. The unencapsulated device maintains 90% of its initial efficiency after 1000 h storage in dark ambient conditions with ≈30% relative humidity. This strategy provides an effective approach for promoting the crystallization process of perovskite and fabricating efficient and stable PSCs.

Multifunctional molecular bridge enabled interface passivation and strain release for stable and efficient all-inorganic perovskite solar cells

The precise management of the buried interface in n-i-p perovskite solar cells (PSCs) to achieve efficient charge extraction and transport is crucial for improving the photovoltaic performance. Here, a 4-chloro-2,5-dimethoxyaniline (CDA) modifier with multifunctional groups is utilized as a molecular bridge at the TiO2/CsPbBr3 buried interface to enhance the qualities of TiO2 and CsPbBr3 films and the arrangement of interface energy level. The chlorine atom in CDA can heal the oxygen vacancies defects on the TiO2 film surface, thereby improving its electron mobility and conductivity. The –O– and -NH2 groups in CDA play a passivation effect on the ions defects of CsPbBr3 film, and especially the two –O– groups can anchor the lattice Pb atoms of CsPbBr3 perovskite, which effectively reduce the trap states of CsPbBr3 film and release the residual lattice strain. The modification of CDA also improves the wettability and energy level of TiO2 film to optimize CsPbBr3 crystal growth and charge transport, respectively. Consequently, the CsPbBr3 PSCs with CDA molecular bridge free of encapsulation achieve a highly increased power conversion efficiency of 10.85%, in contrast with 8.16% value of the control device. After 720 h of storage at 85 °C and in air environment with 85% relative humidity, the efficiency of the CDA-modified device retains 93.1% of the initial value, demonstrating excellent long-term humidity and thermal stability.

High sensitivity, thermal noise-driven aluminum-based resonant MEMS humidity sensor

The integration of connected devices and the Internet of Things in the era of Industry 4.0 has led to the transformation of various sectors. Sensors, particularly for humidity measurement, play a pivotal role in applications such as respiration and wound monitoring, human–machine interfaces, fuel cells, and circuit failure detection. While conventional humidity sensors dominate the market, gravimetric-based sensing offers promise but faces challenges due to complex fabrication, high cost, and nonlinearity. This study explores gravimetric platforms for humidity sensing and proposes linear and nonlinear schemes to detect humidity. The linear sensors exhibit consistent frequency shifts with humidity changes, while the nonlinear sensors introduce a turn-around point where nonlinear effects counteract mass-loading. We address this limitation by splitting the dynamic range into low and high ranges on either side of this point, thereby creating one-to-one relationships. Both sensor types demonstrate high sensitivity (from 39068 to −23568 ppm/%RH for nonlinear and 5809 ppm/%RH for linear) and repeatability, emphasizing their suitability for real-time humidity monitoring. Moreover, the thermal noise-driven resonators underlying the sensors do not require external input, thereby enhancing their suitability for low-power applications. These findings provide a foundation for innovative real-time sensing applications and offer insights into optimizing sensitivity and stability in humidity sensing and other applications.