Excellent Air Stability Research Articles

A review on the application of Sr2Fe1.5Mo0.5O6-based oxides in solid oxide electrochemical cells

The development of solid oxide electrochemical cells (SOCs) coincides with the policy of emission peak and carbon neutrality, and possesses significant commercial prospects in the future energy market. Developing perovskite oxides with mixed oxygen ionic and electronic conductivity is an effective approach to alleviate the issues caused by lowering the operating temperature and the utilization of hydrocarbon fuel. Recently, Sr2Fe1.5Mo0.5O6-δ with double perovskite structure exhibits high conductivity, excellent redox stability and catalytic activity in both air and hydrogen environments, and presents broad application prospects in SOCs. Surface modification and element doping further enhance the electro-catalytic activity of the Sr2Fe1.5Mo0.5O6-δ electrode, enabling a broader application prospect in SOCs. This review summarizes the structures, properties, applications, shortcomings, and optimizations of the Sr2Fe1.5Mo0.5O6-δ-based oxides in detail. The research and development of the Sr2Fe1.5Mo0.5O6-δ-based oxides have specific guidance and assistance for the progress of intermediate temperature SOCs.

Bicyclic-ring base doping induces n-type conduction in carbon nanotubes with outstanding thermal stability in air

The preparation of air and thermally stable n-type carbon nanotubes is desirable for their further implementation in electronic and energy devices that rely on both p- and n-type material. Here, a series of guanidine and amidine bases with bicyclic-ring structures are used as n-doping reagents. Aided by their rigid alkyl functionality and stable conjugate acid structure, these organic superbases can easily reduce carbon nanotubes. n-Type nanotubes doped with guanidine bases show excellent thermal stability in air, lasting for more than 6 months at 100 °C. As an example of energy device, a thermoelectric p/n junction module is constructed with a power output of ca. 4.7 μW from a temperature difference of 40 °C.

Silver Ion-Induced Formation of Unprecedented Thorium Nonamer Clusters via Lacuna-Construction Strategy

Silver Ion-Induced Formation of Unprecedented Thorium Nonamer Clusters via Lacuna-Construction Strategy

Highly stable metal halides Cs2ZnX4 (X = Cl, Br) with Sn2+ as dopants for efficient deep-red photoluminescence

The development of deep-red emitting lead-free metal-halide perovskites with high photoluminescence quantum yields (PLQYs) and outstanding stability remains a major challenge for displays and deep-tissue bioimaging. In this work, we report a facile and convenient solvothermal method to synthesize metal halides Cs2ZnX4 (X = Cl, Br) that however is PL innert at room temperature. Upon composition engineering utilizing Sn2+ as the dopant, the resulting Cs2ZnCl4:Sn not only emits strong deep-red PL peaked at 700 nm with the highest 99.4% PLQY among the similar materials so far, but also exhibits excellent structure stability in air (PLQY remains 96% after one year exposure to the atmosphere). Detailed experimental characterizations and theoretical calculations reveal that the deep-red emission stems from self-trapped excitons induced by the Sn2+ dopant. Particularly, triplet emission (3P2→1S0) from Sn-5s2 orbitals has been observed at low temperature due to the break of parity-forbidden transition. This work provides an important guidance for the development of deep-red light-emitting materials with low price, high efficiency and excellent stability.

Charge Balance in Red QLEDs for High Efficiency and Stability via Ionic Liquid Doping

AbstractColloidal quantum dot light‐emitting diodes (QLEDs) simultaneously exhibiting high external quantum efficiency (EQE) and operation stability are achieved via a simple solution processing. A silver bis(trifluoromethane‐sulfonyl)imide treatment that is used to chemically dope the poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) hole injection layer (HIL) is proposed. The ionic liquid salt acts as an effective p‐dopant for high charge concentrations; and it raises the work functions and surface potentials of the PEDOT:PSS HIL for an interface energy band alignment. Benefiting from a raised hole mobility and a better charge mobility balance, the processing‐simple colloidal red QLEDs yielded the highest EQE of up to 17.4%. In particular, a very broad plateau of EQE values over 16.5% in the brightness of 400–10 000 cd m−2 is obtained. Moreover, the packaged QLEDs exhibit an excellent operation stability in ambient air. The T95 (time for the device brightness to decrease to 95% of its initial brightness) at an initial brightness of 1000 cd m−2 is 4160 h. The work highlights a promising ionic liquid strategy to guide the development of high‐performance and cost‐effective QLEDs.

Air Stable Chalcogen-Doped Rubicenes with Diradical Character

Air Stable Chalcogen-Doped Rubicenes with Diradical Character

Air‐Stabilized Lead‐Free Hexagonal Cs3Bi2I9 Nanocrystals for Ultrahigh‐Performance Optical Detection

AbstractBroadband photodetectors possess enormous potentials for diverse applications while it is generally subjected to a lack of active materials with high performances under user‐friendly conditions. Bismuth‐based perovskites are promising and demonstrate better air stability than lead halide perovskites against moisture, heat, and light. In the present work, lead‐free all‐inorganic hexagonal Cs3Bi2I9 perovskite nanocrystals are successfully fabricated via a modulated colloidal synthetic route. The Cs3Bi2I9 nanocrystals are monodispersed with a size of ≈28 nm, which are applied for the construction of flexible Cs3Bi2I9 detector and vertical heterogeneous structured photodetector of p‐Si/Cs3Bi2I9/graphene. The flexible detector not only demonstrates excellent detective performance, but also yields high‐resolution photographs as an imaging sensor. The p‐Si/Cs3Bi2I9/graphene photodetector exhibits broad spectral response from ultraviolet to infrared light (254−1064 nm) with microsecond response time (31/34 µs). In particular, it performs with a high responsivity of 23.6 A W−1 and a high specific detectivity of 1.75 × 1013 Jones under 650 nm illumination even in weak light intensity as low as 1 µW cm−2, and exhibits excellent stability in ambient air, which is obviously ahead of the previously reported work. In addition, finite element analysis further demonstrates the excellent optoelectronic properties of Cs3Bi2I9 materials and the broad spectral response of vertical heterojunctions.

Bright-dark-bright soliton generation in erbium-doped fiber laser based on Pb3Sn4FeSb2S14 saturable absorber

Pb3Sn4FeSb2S14, a novel two-dimensional layered material, exhibits competitive properties, including a hexagonal crystal structure and excellent air stability. It has a relatively low bandgap value of 0.65 eV and is similar to the structure of franckeite, showing alternating segregation of Sn-rich and Pb-rich layers. In this paper, an erbium-doped fiber laser was successfully fabricated using the multi-element compound Pb3Sn4FeSb2S14 as a saturable absorber. In the experiment, the bright-dark-bright pulsed laser output was observed when the pump power was between 200 mW and 550 mW. The two central wavelengths were 1559.10 and 1559.78 nm. The fundamental repetition frequency of the pulse was 1.64 MHz and the signal-to-noise ratio (SNR) was about 48 dB. The results demonstrate that Pb3Sn4FeSb2S14 is an effective modulator for bright-dark-bright soliton fiber lasers due to its good nonlinear saturation absorption characteristics.

On-chip integration of 2D Van der Waals germanium phosphide (GeP) for active silicon photonics devices.

The outstanding performance and facile processability turn two-dimensional materials (2DMs) into the most sought-after class of semiconductors for optoelectronics applications. Yet, significant progress has been made toward the hybrid integration of these materials on silicon photonics (SiPh) platforms for a wide range of mid-infrared (MIR) applications. However, realizing 2D materials with a strong optical response in the NIR-MIR and excellent air stability is still a long-term goal. Here, we report a waveguide integrated photodetector based on a novel 2D GeP. This material uniquely combines narrow and wide tunable bandgap energies (0.51-1.68 eV), offering a broadband operation from visible to MIR spectral range. In a significant advantage over graphene devices, hybrid Si/GeP waveguide photodetectors work under bias with a low dark current of few nano-amps and demonstrate excellent stability and reproducibility. Additionally, 65 nm thick GeP devices integrated on silicon waveguides exhibit a remarkable photoresponsivity of 0.54 A/W and attain high external quantum efficiency of ∼ 51.3% under 1310 nm light and at room temperature. Furthermore, a measured absorption coefficient of 1.54 ± 0.3 dB/µm at 1310 nm suggests the potential of 2D GeP as an alternative infrared material with broad optical tunability and dynamic stability suitable for advanced optoelectronic integration.

Synergistic effect of TiH2 and air exposure on enhancing hydrogen storage performance of Mg2NiH4

Air stability of magnesium-based hydrogen storage materials is one of the key challenges for its large-scale application, as the hydrides could be oxidized easily during air exposure. In this work, TiH2 and graphite were added into magnesium nickel hydride (Mg2NiH4) by short-time (0.5 h) mechanical milling to clarify the effect of air exposure on hydrogen storage behavior of the composites. Among the various Mg2NiH4–additive composites, the Mg2NiH4–TiH2 composite showed the highest hydrogen desorption and absorption capacity retention of 76.9 % and 75.6 % after air exposure for 30 days, respectively. It is worth noting that both the hydrogen absorption and desorption kinetics of the composites were enhanced after air exposure, especially for the Mg2NiH4 co-added with TiH2 and graphite composite. The excellent air stability and enhanced hydrogen reaction kinetics of Mg2NiH4–TiH2 composite should be attributed to the ternary-synergistic effect, including the protective effect of passivation layer, catalytic and sacrificial effect of TiH2, and catalysis of in-situ formed Ni-based products. They prevented further oxidation of the active matrix and provided more active sites for hydrogen absorption and desorption reactions. Our findings might guide the design and development of reversible metal hydrides with excellent reaction activity and air stability.

Effect of Steric Hindrance of Butylammonium Iodide as Interface Modification Materials on the Performance of Perovskite Solar Cells

The efficiency and stability of perovskite solar cells (PSCs) can be effectively improved by interfacial modification with butylammonium iodide (BAI). However, the steric hindrance of BAI is not explored. Herein, BAI with different steric hindrances, that is, n‐BAI, iso‐BAI (i‐BAI), and tert‐BAI (t‐BAI), are systematically studied as interface modification materials between (FAPbI3)0.95(MAPbBr3)0.05 and spiro‐OMeTAD in PSCs. It is found that the efficiency and humidity stability of devices gradually increase in the order of t‐BAI‐, i‐BAI‐, n‐BAI‐modified ones. This seems that the larger steric hindrance hinders BAI diffusion to the grain boundary, resulting in the reduction of grain boundary passivation and the residue of excessive BAI on the surface of perovskite films. Excessive BAI is equivalent to new defects and can block hole transport. As the steric hindrance increases from n‐BAI to i‐BAI, and further to t‐BAI, the device with n‐BAI modification shows the highest power conversion efficiency (PCE) of 20.67% with excellent stability in air with a humidity of 20–30%, keeping 80% of the original PCE after 60 days. It is believed that this study can guide the structural selection of modified materials at the interface between perovskite and hole transport layer with n–i–p structure.

Highly Stable and Efficient Mn2+ Doping Zero-Dimension Cs2ZnxPb1-xCl4 Alloyed Nanorods toward White Electroluminescent Light-Emitting Diodes.

Zero-dimensional (0D) crystal structure perovskite NCs have reemerged as promising materials owing to their superior long-term stability; however, their poor conductivity leads to the inferior electrical performances and critically restricts the optoelectronic application of 0D perovskite materials. Herien, the alloyed 0D crystal structure Cs2ZnxPb1-xCl4 nanorods (NRs) have been synthesized by the modified hot-injection method, which emits bright blue-violet light at 408 nm, and the optimized photoluminescence quantum yield (PLQY) reaches 26%. The Cs2Zn0.88Pb0.12Cl4 NRs display more excellent air stability and an order of magnitude higher conductivity than CsPbCl3 nanocube films. In addition, we dope Mn2+ ions into the Cs2Zn0.88Pb0.12Cl4 NRs, which accomplished the optimized PLQY of 40.3% and polarized emission with r = 0.19. The light-emitting diodes (LEDs) based on Mn2+ ion doped Cs2Zn0.88Pb0.12Cl4 NRs exhibit a chromaticity coordinate (CIE) of (0.36, 0.33), an EQE of 0.3%, and a maximum luminance of 98 cd m-2. This work has enriched ideas for the production of white light perovskite LEDs.

Chemically Stable Low-Dimensional Electrides in Transition Metal-Rich Monochalcogenides: Theoretical and Experimental Explorations

Electrides, which are ionic crystals composed of excess anionic electrons, are of great interest as an exotic material for fundamental research and practical applications in broad fields of science and technology. However, an inherent chemical instability under ambient conditions at room temperature has been a fatal drawback to be addressed. Here, we report that transition metal-rich monochalcogenides are an emerging class of low-dimensional electrides with excellent chemical and thermal stability in air and water at room temperature through a comprehensive exploration of theoretical prediction and experimental verification. We predict new two-dimensional (2D) electrides crystallized in hexagonal P3̅m1 and P63/mmc structures with strong localization of anionic electrons in a dumbbell shape at the tetrahedral cavity of the interlayer space, which are distinct from the anionic electrons localized at the octahedral cavity in the hexagonal R3̅m structure of the previous 2D [Ca2N]+·e- and [Y2C]2+·2e- electrides. We successfully synthesized the room-temperature stable [Ti2O]2+·2e-, [Ti2S]2+·2e-, [Zr2S]2+·2e-, and primary solid solution [Hf2SxSe1-x]2+·2e- electrides, showing no structural degradation in air and water. Among them, we found that the synthesized [Ti2S]2+·2e- and [Zr2S]2+·2e- electrides are crystallized in orthorhombic symmetry (Pnnm), showing the feature of a one-dimensional (1D) electride with an anionic electron chain, which has never been reported yet. In addition to the successful finding of new 1D and 2D electrides, we discuss the self-passivation effect-driven chemical stability and the role of anionic electrons in determining the physical properties of the newly discovered electrides.

Intermediate Phase‐Assisted Sequential Deposition Toward 15.24%‐Efficiency Carbon‐Electrode Cspbi2br Perovskite Solar Cells

All‐inorganic perovskite CsPbI2Br is emerging as a promising absorber material for perovskite solar cells (PSCs) due to its superior photophysical properties and thermal stability. However, there are still many great challenges to obtaining high‐quality, phase‐stable, thick CsPbI2Br films in ambient air to promote further development of the PSCs. Herein, for the first time, an intermediate phase‐assisted sequential deposition for desired CsPbI2Br films is proposed. It is carried out by sequentially spin‐coating PbBr2 and CsI precursors onto the substrate in ambient air, during which a Ruddlesden–Popper (R–P) perovskite intermediate phase film composed of a Cs‐Pb‐I‐Br complex is produced. After annealing, the intermediate phase film is transformed into a CsPbI2Br film consisting of CsPbI2Br grains and CsBr species through a spinodal decomposition reaction. The as‐obtained CsPbI2Br film holds full coverage, micro‐sized grains, and excellent phase stability. Moreover, the CsBr species located at grain boundaries can effectively passivate the defects. Therefore, a carbon‐electrode PSC with such a desired CsPbI2Br film yields the optimized efficiency of 15.24%, coupled with a remarkable photovoltage of 1.312 V and excellent stability in ambient air with relative humidity of 60–70%. The efficiency achieved herein is among the record efficiencies for carbon‐electrode PSCs based on various all‐inorganic perovskites reported currently.

Highly active and stable BaCo0.8Zr0.1Y0.1O3-δ cathode for intermediate temperature solid oxide fuel cells

Developing cathode material with high performance and excellent stability is the ultimate goal for solid oxide fuel cells (SOFCs). Based on this consideration, we design a new simple perovskite oxide BaCo0.8Zr0.1Y0.1O3-δ (BCZY) as the cathode material of SOFC without any further modification, which has good oxygen reduction reaction (ORR) activity and excellent stability in air and CO2 at an intermediate temperature range of 600 ℃− 800 ℃. The area specific resistance (ASR) of symmetrical cell with BCZY cathode is 0.041 Ω cm2 at 700 ℃, moreover, BCZY cathode keeps good structural and catalytic stability during 100 h test in air. The electrolyte-supported single cell fabricated with BCZY as cathode delivers a maximum power density of 460 mW cm−2 and a superior steady operation over 200 h at 700 ℃. The good thermal physical structure stability of BCZY is further demonstrated by in-situ X-ray diffraction (XRD), good ORR activity and excellent CO2 tolerance are further confirmed by density functional theory (DFT) calculations. These results indicates that BCZY maybe a potential cathode material for intermediate temperature SOFCs (IT-SOFCs).

Transition from metal to semiconductor by semi-hydrogenation of borophene

Borophene has triggered a surge of interest due to its outstanding properties including mechanical flexibility, polymorphism, and optoelectrical anisotropy. Very recently, a novel semi-hydrogenated borophene, called ${\ensuremath{\alpha}}^{\ensuremath{'}}$-4H, was synthesized in large-scale freestanding samples, exhibiting excellent air-stability and semiconducting nature. Herein, using the density functional theory (DFT) and many-body perturbation theory (MBPT), we investigate the electronic and excitonic optical properties of ${\ensuremath{\alpha}}^{\ensuremath{'}}$-4H borophene. The DFT results reveal that hydrogenation breaks the mirror symmetry and increases the buckling height of pure ${\ensuremath{\alpha}}^{\ensuremath{'}}$ borophene, which results in an orbital hybridization and indirect band gap of 1.49 eV in ${\ensuremath{\alpha}}^{\ensuremath{'}}$-4H borophene. Moreover, the optical spectrum achieved from solving the Bethe-Salpeter equation (i.e., $\mathrm{GW}+\mathrm{BSE}$) shows an optical band gap of 2.40 eV, which corresponds to a strongly bound and stable bright exciton with a binding energy of 1.18 eV. The mean value of absorption within the visible area is 1.68 (1.13)$\ifmmode\times\else\texttimes\fi{}{10}^{7}\phantom{\rule{4pt}{0ex}}{\mathrm{m}}^{\ensuremath{-}1}$ for $E\ensuremath{\parallel}x$ ($E\ensuremath{\parallel}y$) polarization, which shows a linear dichroism for visible light. The effective mass and Bohr radius of the ground-state exciton are 0.78 ${m}_{0}$ and 2.03 \AA{}, respectively, which demonstrates the characteristics of Frenkel exciton. The excitonic states are robust against tension up to 10%, under which the monolayer is dynamically stable. We also study the bilayer ${\ensuremath{\alpha}}^{\ensuremath{'}}$-4H borophene with different stackings. For the weak van der Waals interactions between the layers, the bilayer preserves most of the structural and electronic properties of the monolayer. Our study exposes the underlying physics behind the structural, electronic, and optical properties of ${\ensuremath{\alpha}}^{\ensuremath{'}}$-4H borophene and suggests it as a very promising candidate for flexible optoelectronic applications.

Black PEO coating with enhanced thermal stability on titanium alloy and its thermal control properties

A black thermal control ceramic coating with high absorption (200–2500 nm, >0.95) and emission (2.5–16 μm, >0.92) was successfully prepared on the surface of Ti6Al4V alloy by plasma electrolytic oxidation with the coloring additives of NH 4 VO 3 , FeSO 4 and Co(CH 3 COO) 2 . The coating composition, surface morphology and thermal control performance were studied in detail. Results showed that the transition metal elements in the coating had various valence states, which presented Ti 4+ , Fe 3+ , Co 2+ , Co 3+ , V 3+ , V 4+ and V 5+ , and existed in the form of oxides. Among them, the total content of V 3+ and V 4+ was increased with the increase of PEO time. Besides, there were some micro-pores and nano-pores on the coating surface. With the increase of PEO reaction time, the number of micro-pores got reduced while their size was increased. Before 20 min of reaction, the improvement of the absorption and emission was mainly due to the semiconductor properties, d-d transition and infrared stretching vibration of transition metal oxides. As the reaction proceeds, the complex porous structure on the surface also played a major role in improving the absorption and emission. Moreover, the coating showed excellent thermal stability in air up to 300 °C or oxygen deficient environment up to 500 °C, which provided a possibility for practical application. • A black coating with high absorptivity and emissivity is prepared by PEO. • The thermal control performance is related to the valence of transition metals. • The porous structure is beneficial to improve the thermal control performance. • The coating has excellent thermal stability both in air and in Ar.

A multifunctional ligand for defect passivation of perovskite film realizes air-stable perovskite solar cells with efficiencies exceeding 20%

High-performance ambient-stable perovskite solar cells have been obtained after incorporating dtdn and urea into the perovskite. The best device performance featured a power conversion efficiency of 20.64% with excellent air-stability for 720 h.

Enhanced Raman scattering on two-dimensional palladium diselenide.

Two-dimensional (2D) semiconductors with atomic layers, and a flat and active surface provide an attractive platform for the study of surface-enhanced Raman scattering (SERS). Many 2D layered materials, including graphene and transition metal dichalcogenide (TMD), have been exploited as potential Raman enhancers for SERS-based molecule sensing. Herein, atomically-thin palladium diselenide (PdSe2) used as a SERS substrate for molecule detection was systematically studied. Stable Raman enhancement for molecules such as rhodamine 6G (R6G), crystal violet (CV), and rhodamine B (RhB) on few-layer PdSe2 has been verified. A detection limit as low as 10-9 M and an enhancement factor of 105 for the R6G molecule on monolayer PdSe2 are achieved. With the insertion of a thin Al2O3 layer, the Raman spectra confirm the predominant charge transfer mechanism for the large Raman enhancement. Furthermore, the strong thickness-dependent properties, good in-plane anisotropy and excellent air-stability of Raman enhancement are also explored for 2D PdSe2. Our findings provide not only a promising Raman enhancement platform for sensing applications but also new insights into the chemical mechanism (CM) process of SERS.

Smart construction of multifunctional Li1.5Al0.5Ge1.5(PO4)3|Li intermediate interfaces for solid-state batteries

Due to high ionic conductivity, low cost and excellent air stability, NASICON-type Li1.5Al0.5Ge1.5(PO)4 (LAGP) electrolyte has been a promising candidate for high-performance solid-state batteries. Nevertheless, the poor interfacial compatibilities between LAGP and lithium (Li) metal (i.e., intrinsic instability of LAGP to metallic Li, growth of dendrite Li) retard its commercial application. Herein, a nano multifunctional LiF@Li-zinc (Zn) alloy layer consisting of electrically insulated but ionic conductive lithium fluoride (LiF) and Li-Zn alloy is introduced at the LAGP|Li interface (Z-LAGP) by in-situ conversion reactions. Such LiF@Li-Zn layer not only leads to stable and tight interface with low resistance and effective inhibition of side reactions, but also homogenizes the Li-ion flux with free of dendrite Li. Consequently, the Li|Z-LAGP|Li cells present the improved critical current density as high as 2.0 mA cm−2, stable cycles with longer than 1000 h at 0.1 mA cm−2, and as well as superior cycling performance from 0.1 to 0.5 mA cm−2 with stable overpotential. What is more, the solid-state batteries of Li|Z-LAGP|LiFePO4 show the good cycle stability with highly reversible capacity (>150 mA h g−1) at 0.1 C under room temperature. This work highlights a rational design for the robust LAGP|Li interface and a novel strategy to optimizing interfacial compatibilities.