Impurity Energy Research Articles

Effect on In3+ co-doping on photoluminescence and scintillation properties of LYSO:Ce crystal

In this work, a series of LYSO:0.03at.% Ce,xat.%In (x=0, 0.001, 0.005 and 0.01) crystals were successfully grown for the first time by the optical floating zone (FZ) method. The effect of In3+ co-doping on photoluminescence and scintillation properties of LYSO:Ce scintillation single crystal was investigated. It was found that at x = 0.001, the overall scintillation performance was optimized. This was attributed to the fact that In3+ co-doping reduces the concentration of Ce2 emission center and accelerates the photoluminescence decay time of Ce3+. The temperature dependence of photoluminescence of unco-doping and 0.001at.% In3+ co-doping samples was also investigated. Combined with density functional theory calculation, the phenomenon of In3+ co-doping leading to a decrease in quenching temperature of decay time was explained in terms of both crossover relaxation and introduction of impurity energy levels.

Erosion enhancement by impurity entrainment in the highly collisional plasmas of Magnum-PSI

Abstract Extrinsic impurity seeding is planned for ITER to avoid high heat fluxes to the tungsten divertor targets. Nevertheless, excessive sputtering by impurities would lead to a reduction in fusion power output and divertor lifetime. Unlike today's fusion devices, the entrainment of impurities is expected to play an increasing role in ITER's highly collisional near-surface plasma. Impurity entrainment refers to the acceleration of impurities with the plasma flow by collisional drag, leading to elevated impact energies. To investigate impurity entrainment under ITER-like plasma conditions ($n_e > 2 \cdot 10^{20}$ m$^{-3}$, $T_e <$ 5 eV), argon-seeded hydrogen plasmas were formed with the linear plasma generator Magnum-PSI. Doppler shifts in spatially-resolved emission profiles of argon (Ar II - 480.6 nm) and hydrogen (H$_\mathrm{\beta}$ - 486.1 nm) reveal the entrainment of seeded argon towards the upstream hydrogen velocity ($\sim$9 cm from surface), corresponding to $\sim$0.39 of the common-system sound speed. In addition, the sputtering yield of tungsten by argon bombardment for the argon-seeded hydrogen plasma was compared to a pure argon plasma by monitoring tungsten (W I - 400.9 nm) emission. These sputtering experiments indicate further entrainment of the argon impurities to $\sim$0.65 of the common-system sound speed at the sheath edge, leading to a large increase in their impact energy. Extrapolation of the Magnum-PSI results to ITER, using existing SOLPS-ITER simulations to determine the divertor plasma conditions, indicates more than an order of magnitude increase in gross erosion of the divertor targets due to impurity entrainment. However, the net erosion rate could still be kept under control if high re-deposition rates are achieved, which is treated in the companion paper \cite{Cornelissen2023}. The combination of a low sputtering threshold energy and high impact energy of impurities constrains the fine balance between radiative cooling with impurity seeding and avoiding extensive divertor erosion.

Large Optical Nonlinearity Enhancement and All‐Optical Logic Gate Implementation in Silver‐Modified Violet Phosphorus

AbstractAs the most stable allotrope of phosphorus, violet phosphorus (VP) has attracted extensive research in the field of all‐optical modulation due to its excellent broadband spatial self‐phase modulation (SSPM) effect. To better exploit the great potential of VP in nonlinear photonics devices, this work explores chemical doping method to artificially enhance the nonlinear optical response of VP. Herein, silver‐modified few‐layer VP (Ag‐VP) is constructed for SSPM experiments. In comparison to pristine VP, a significantly improved third‐order nonlinear susceptibility (χ(3)) and nonlinear optical response for Ag‐VP is obtained in visible light band, and the enhancement ratio increases with the increase of wavelength. Moreover, the excitation threshold of SSPM effect is also significantly reduced, with a reduction ratio up to 3.61. The enhanced nonlinear optical response is attributed to the improved light–matter interaction induced by impurity energy levels. By taking advantage of the outstanding SSPM effect of Ag‐VP, an all‐optical logic gate is designed to demonstrate “OR” logical information transmission. This work provides a new avenue for the design and application of energy‐saving and tunable nonlinear photonic devices in the future.

Enhancing solar-driven hydrogen production through photoelectrochemical methods via dual transition metal doping of titanium oxide to form an impurity energy band

Developing a photoanode that is stable, efficient, and cost-effective for photoelectrochemical water splitting poses a significant challenge. To address this, we have successfully synthesized cobalt and chromium-doped Titanium dioxide (CoCrTiO2) using the hydrothermal method. This innovative approach results in an efficient, stable, and economical material. The introduction of Co and Cr through doping creates an intermediate band energy within TiO2, thereby enhancing charge separation and movement. The performance of CoCrTiO2 in the photoelectrochemical water splitting process is noteworthy. At 0 V vs Ag/AgCl, CoCrTiO2 exhibits a photocurrent density of 3.45 mAcm−2, representing an impressive 8.5 times increase compared to bare TiO2. Furthermore, when employed as a photoanode, CoCrTiO2 demonstrates a significant increase in hydrogen production. The amount of hydrogen generated is measured at 67.8 μmolecm−2, surpassing bare TiO2 by a factor of 5.6. Analysis data strongly supports CoCrTiO2 as an excellent candidate for advancing the field of photoelectrochemical water splitting due to its exceptional performance characteristics.

Fundamental optical transitions in hexagonal boron nitride epilayers

Fundamental optical transitions in hexagonal boron nitride (h-BN) epilayers grown on sapphire by metal–organic chemical vapor deposition (MOCVD) using triethylboron as the boron precursor have been probed by photoluminescence (PL) emission spectroscopy. The low temperature (10 K) PL spectrum exhibits two groups of emission lines. The first group includes the direct observation of the free exciton and impurity bound exciton (BX) transitions and phonon replicas of the BX transition, whereas the second group is attributed to the direct observation of the band-to-band transition and its associated phonon replicas. The observations of zero-phonon lines of the band-to-band and exciton transitions, which are supposedly forbidden or “dark” in perfect h-BN crystals, result from a relaxed requirement of momentum conservation due to symmetry-breaking in the presence of high concentrations of impurities/defects and strain, which in turn provided more deterministic values of the energy bandgap (Eg), exciton binding energy (Ex), and binding energy of impurity bound excitons (EBX) in h-BN epilayers. Excitonic parameters of h-BN epilayers grown by MOCVD, carbon-free chemical vapor deposition, and high purity h-BN bulk materials are compared and discussed. The present results, together with available information in the literature, represent a significant improvement in the understanding of the fundamental optical properties and excitonic parameters of h-BN ultrawide bandgap semiconductors.

Effect of oxygen vacancy engineering on hybrid conduction mechanism in Ce doped La1-xCexBaCo2O5 ceramics

The La1-xCexBaCo2O5 (x = 0.05, 0.1, 0.15, 0.2) thermosensitive ceramics with negative temperature coefficient (NTC) were synthesized using a conventional solid-phase method. X-ray diffraction analysis (XRD) revealed that La1-xCexBaCo2O5 possesses an orthorhombic perovskite structure. Scanning electron microscopy (SEM) showed a uniform and dense ceramic microstructure, with grain size initially increasing and then decreasing as the Ce content rises. X-ray photoelectron spectroscopy (XPS) data reveal the presence of oxygen vacancies and Co3+/Co2+ ion pairs within the material, showing concentrations that increase with Ce content. The resistance temperature profiles indicate the presence of a hybrid conductive mechanism in the material. In the temperature range of 2–20 K, the conductive mechanism of the material conforms to Mott's 3D VRH conduction model. When the temperature is 20–77 K, the conductive mechanism of the material is consistent with the small polariton conduction model. In addition, the mechanism of the mixed effect of oxygen vacancy concentration on the conductivity of the material is explained to elucidate the electron hopping transport conductivity mechanism of NTC thermal ceramics. First-principle calculations demonstrate that oxygen vacancies introduce new impurity energy levels and pathways for electron transport, enhancing the ceramics' electrical conductivity. These findings highlight the ceramic samples' favorable NTC characteristics and electrical conductivity across the temperature range 2–77 K, offering new possibilities for applications in extremely low-temperature NTC thermistors.

Developing Rapid-Charging Li-S Batteries via "Target Catalysis" of Cations and Anions Modified Electrocatalyst.

The shuttle effect and sluggish sulfur reduction reaction have resulted in significantly low efficiency and poor high current cycling stability in lithium-sulfur batteries, impeding their practical applications. To address these challenges, the introduction of Ni cations into MoS2 grown on reduced graphene oxide (MoS2/rGO) induces the formation of impurity energy levels between the conduction and valence bands of MoS2. Additionally, the introduction of anionic Se expands the interlayer spacing, enhances intrinsic conductivity, and improves ion diffusion rates. Simultaneously introducing anionic and cationic species into the MoS2/rGO causes the center of the d-band to shift upward, reducing the occupancy of electrons in antibonding orbitals. This modification leads to a rearrangement of the electronic structure of Mo, accelerating the redox reactions of lithium polysulfides. It particularly enhances the binding energy and lowers the conversion energy barrier of Li2S4. Consequently, the Li||S coin cell with the Ni-MoSSe/rGO cathode demonstrates an initial capacity of 446 mAh g-1 at 20 C, with a remarkable capacity retention of ≈96.7% after 200 cycles. Moreover, even under high sulfur loading conditions (6.45 mg cm-2) and a low electrolyte/sulfur ratio (5.4 µL mg-2), it maintains a high areal capacity of 6.42 mAh cm-2.

Photocatalytic hydrogen evolution boosted by C, N co-doped TiO2 (101): Mechanistic insights from a combined computational and experimental investigation

Non-metallic modified TiO2 has been proven to be an effective approach for promoting photocatalytic performance. However, the catalytic mechanism remains largely unclear. In this work, we discovered that the N atom occupied interstitial positions or displaced O atom in bulk exhibited remarkable photocatalytic hydrogen evolution activity in the absence of oxygen vacancies (Ov). Furthermore, the presence of Ov at the surface will introduce the Ti3+ species and resulting in a downward shift of the d-band center. Importantly, the impurity energy levels coupled with Ti (3d), O (2p), C (2p), and N (2p) orbitals below the conduction band further facilitate the separation of photogenerated e−/h+ pairs and further enhance light absorption, the optimal system exhibiting a ΔG of −0.02 eV. Subsequently, the synthesis of the predicted C, N co-doped TiO2 was carried out. The photocatalytic hydrogen evolution rate reached 795 μmolg−1h−1 at 400 nm. This work provides unprecedented atomistic insights into the photocatalytic hydrogen evolution reaction.

Electronic and photocatalytic properties of Cu4 cluster-modified Ag/g-C3N4 single-atom catalysts: A hybrid DFT study

Increasing the active sites on the catalyst surface has been a key goal to increase the catalyst efficiency. This paper presents an efficient conversion of solar energy into chemical energy, realized by a Cu4 cluster-assisted single-atom catalyst (Ag-doped g-C3N4). The catalyst enhances charge transfer and light absorption, and the unique advantages of this approach in the field of photocatalysis are substantiated by density functional theory. Under the synergistic effect of Cu4 clusters, the electronic state density distribution of the Ag single-atom catalyst substrate is drastically altered, which realizes the increase of substrate active sites and rapid charge separation and transfer. Compared with the pristine substrate g-C3N4, the new electronic state distribution and the generation of impurity energy levels lead to the narrowing of the band gap from 2.77 to 1.83 eV, accelerating the transfer and separation of electrons and holes, and enlarging the visible light absorption range from 410 to 760 nm, thus improving the solar energy utilization. Despite the reduced band gap, the conduction and valance band edges of (Ag, Cu4) codoped g-C3N4 still have sufficient potential to split water. Therefore, to improve the photocatalytic performance under visible light, simultaneous codoping of the Ag single atom and Cu4 cluster on g-C3N4 is an effective strategy. The study provides theoretical support for further optimization of single-atom catalysts.

Mechanical and electrical properties of two-dimensional BN doped with carbon group elements: first-principles calculations

Abstract Research of low-dimensional nanomaterials provides a direction for solving the problems of energy and environmental pollution. In this work, the regulation mechanism of doping carbon group elements X (X = C, Si, Ge, Pb, Sn) on mechanical and electrical properties of 2D monolayer BN are investigated by first-principles calculations. Two doping sites were selected, replace B atoms (B15N16X) or N atoms (B16N15X). Lower relative enthalpies and the elastic constants, which conforming to the mechanical stability standard, fully prove the stability of the doping system. Compared with B15N16X, B16N15X has larger structural distortion, smaller elastic constants and modulus, and is more inclined to ductility. With the increase of atomic radius, the deformation degree increases and the elastic parameters decrease. C-doped by replacing B atoms improves the elastic mechanical properties of monolayer BN. Sn-doped and Pb-doped modulate the monolayer BN into ductility. More importantly, all doped configurations exhibit magnetism. The indirect band gap of the undoped system can also be modulated into a direct band gap, B15N16C, B16N15Si and B16N15Ge all have direct band gaps in the spin-down direction. Asymmetric impurity energy levels DOS further verify the magnetism of the reference system.

Selective Photocatalytic Oxidation of 5‐Hydroxymethylfurfural using Ce doped TiO2: A Crucial Role of Defective Sites

AbstractTransforming platform compounds with conventional catalysts, such as homogeneous and heterogeneous, into valuable chemicals encounters challenges associated with entailing high temperature/pressure and reusability during the reaction. To address these challenges, photocatalysis is one of the promising approaches, especially with visible‐light‐driven photocatalysts for selective transformation. A series of cerium‐doped TiO2 (CexTiO2; x=0.5, 1, 3 and 5 wt %) are prepared via a simple coprecipitation method for the cocatalyst‐free selective oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐diformylfuran (DFF) under visible light illumination. Introducing Ce into the network to TiO2 generates impurity energy levels, reduces the band gap, and extends the spectral response range. This also causes slight distortion to the surface structure, thereby originating defective sites and various surface oxygen species, confirmed by X‐ray photoelectron spectroscopy and electron paramagnetic resonance studies. The HMF adsorption studies infer that HMF forms a surface complex with CeTiO2, facilitating the formation of ligand‐to‐metal charge transfer complex (LMCT) under visible light (~420 nm), which efficiently catalyzes the conversion of HMF (54.4 %) to DFF with a selectivity of >99 %. In‐situ DRIFTS and surface passivation studies provide insight into the interaction between HMF and surface acidic/basic sites along with hydroxyl groups of CeTiO2, which subsequently convert selectively to DFF.

Effect mechanism of Cd on band structure and photocatalytic hydrogen production performance of ZnS

ZnS is widely used in the photocatalytic decomposition of water to produce hydrogen due to its fast electron-hole pair generation and high negative potential. However, its absorption in the visible region is poor due to its wide band gap, and it has serious photogenerated carrier recombination problems. Herein, a shallow impurity energy level was introduced by doping the ZnS lattice with Cd. Due to its presence, electrons trying to return to the valence band are trapped and excited twice, suppressing the recombination of photogenerated carriers and greatly improving electron utilization. The Cd1.5-ZnS possesses a hydrogen production rate as high as 85722.20 μmol/g, which is 17 times higher than pure ZnS. Meanwhile, Cd1.5-ZnS has a narrower forbidden band and superior visible light absorption, and the serious photocorrosion problem of ZnS has been suppressed. This study provides a viable approach for the synthesis of photocatalysts with adjustable band gaps and enhanced hydrogen precipitation efficiency.

Nitrogen-doped ZnIn2S4 and TPA multi-dimensional synergistically enhance photocatalytic hydrogen production

To alleviate the environmental pollution and energy crisis caused by the excessive use of fossil fuels, photocatalytic water splitting to produce hydrogen is an important way to solve energy and environmental problems. Here, Nitrogen-doped ZnIn2S4 (N-ZIS) composite tungsten-based polyoxometalate (TPA) composites (denoted as N-ZIS/TPA) were synthesized by a one-step solvothermal method. The introduction of N3– instead of S2− in ZIS changes the internal electron arrangement of ZIS, improves the electronegativity of ZIS, and is conducive to the surface adsorption of positively charged H*. At the same time, the impurity energy level is generated at the valence band position, which narrows the band gap and broadens the light absorption range, thereby promoting photocatalytic hydrogen production. After compounding, due to the adjustable redox properties of TPA itself, the internal W6+ part is reduced to W4+, resulting in the coexistence of W6+ and W4+ in the composite material, which fully verifies the flow of interface electrons from N-ZIS to TPA. The close contact between N-ZIS and TPA and the built-in electric field’s driving force help achieve efficient interfacial charge transfer. At the same time, W6+/W4+ redox pairs were introduced to accelerate the separation of photogenerated electrons and holes. The photocatalytic hydrogen production rate of the best sample 1N-ZIS/TPA-15 is as high as 17345.53 μmol·g−1·h−1, which is 2.92 times that of N-ZIS (5940.08 μmol·g−1·h−1) and 8.03 times that of ZIS (2159.22 μmol·g−1·h−1). This study explores the design and construction of efficient s-type heterojunctions by adjusting the energy band position of ZnIn2S4 as a new strategy in the field of photocatalytic hydrogen production.

Effects of CeO2 doping on the mechanical, infrared radiative, and thermophysical properties of Pr2Zr2O7 ceramics for potential thermal protective coatings

A series of Ce4+-doped Pr2Zr2O7 ceramics were produced using a solid reaction method to utilize novel ceramic materials as potential candidates for thermally protective coatings. The effects of Ce4+ doping on the phase composition and mechanical, infrared radiative, and thermophysical properties were studied in detail. The results indicated the good phase stability and sintering resistance of the Pr2(Zr1−xCex)2O7 ceramics. Moreover, Ce4+-doped Pr2Zr2O7 bulk materials exhibited higher infrared emissivity (0.904) at wavelengths of 3–5 μm and 1000 °C for Pr2(Zr0.5Ce0.5)2O7) owing to the introduction of impurity energy levels. Pr2(Zr0.7Ce0.3)2O7 exhibited an appropriate average coefficient of thermal expansion of 12.4 × 10−6 K−1 and a low thermal conductivity of 1.14 W m−1 K−1 at 1000 °C, owing to the reduction of lattice energy and the presence of more oxygen vacancies and substitution atoms.

Fluorine Doping Mediated Epitaxial Growth of NaREF4 on TiO2 for Boosting NIR Light Utilization in Bioimaging and Photodynamic Therapy

AbstractBy integrating TiO2 with rare earth upconversion nanocrystals (NaREF4), efficient energy transfer can be achieved between the two subunits under near‐infrared (NIR) excitation, which hold tremendous potential in the fields of photocatalysis, photodynamic therapy (PDT), etc. However, in the previous studies, the combination of TiO2 with NaREF4 is a non‐epitaxial random blending mode, resulting in a diminished energy transfer efficiency between the NaREF4 and TiO2. Herein, we present a fluorine doping‐mediated epitaxial growth strategy for the synthesis of TiO2‐NaREF4 heteronanocrystals (HNCs). Due to the epitaxial growth connection, NaREF4 can transfer energy through phonon‐assisted pathway to TiO2, which is more efficient than the traditional indirect secondary photon excitation. Additionally, F doping brings oxygen vacancies in the TiO2 subunit, which further introduces new impurity energy levels in the intrinsic band gap of TiO2 subunit, and facilitates the energy transfer through phonon‐assisted method from NaREF4 to TiO2. As a proof of concept, TiO2‐NaGdF4 : Yb,Tm@NaYF4@NaGdF4 : Nd@NaYF4 HNCs were rationally constructed. Taking advantage of the dual‐model up‐ and downconversion luminescence of the delicately designed multi‐shell structured NaREF4 subunit, highly efficient photo‐response capability of the F‐doped TiO2 subunit and the efficient phonon‐assisted energy transfer between them, the prepared HNCs provide a distinctive nanoplatform for bioimaging‐guided NIR‐triggered PDT.

Fluorine Doping Mediated Epitaxial Growth of NaREF4 on TiO2 for Boosting NIR Light Utilization in Bioimaging and Photodynamic Therapy.

By integrating TiO2 with rare earth upconversion nanocrystals (NaREF4), efficient energy transfer can be achieved between the two subunits under near-infrared (NIR) excitation, which hold tremendous potential in the fields of photocatalysis, photodynamic therapy (PDT), etc. However, in the previous studies, the combination of TiO2 with NaREF4 is a non-epitaxial random blending mode, resulting in a diminished energy transfer efficiency between the NaREF4 and TiO2. Herein, we present a fluorine doping-mediated epitaxial growth strategy for the synthesis of TiO2-NaREF4 heteronanocrystals (HNCs). Due to the epitaxial growth connection, NaREF4 can transfer energy through phonon-assisted pathway to TiO2, which is more efficient than the traditional indirect secondary photon excitation. Additionally, F doping brings oxygen vacancies in the TiO2 subunit, which further introduces new impurity energy levels in the intrinsic band gap of TiO2 subunit, and facilitates the energy transfer through phonon-assisted method from NaREF4 to TiO2. As a proof of concept, TiO2-NaGdF4 : Yb,Tm@NaYF4@NaGdF4 : Nd@NaYF4 HNCs were rationally constructed. Taking advantage of the dual-model up- and downconversion luminescence of the delicately designed multi-shell structured NaREF4 subunit, highly efficient photo-response capability of the F-doped TiO2 subunit and the efficient phonon-assisted energy transfer between them, the prepared HNCs provide a distinctive nanoplatform for bioimaging-guided NIR-triggered PDT.

Creating electron traps in BiOBr nanosheet arrays by bulk-phase F doping to restrain carrier recombination for efficient photoelectrochemical water splitting system

Bismuth oxide semiconductors in the field of photoelectrochemical (PEC) water splitting face the problems of narrow photo response range and fast carrier compounding. On the basis of the above problems, we used a solvothermal method to prepare BiOBr nanosheet arrays (NSAs), which have a special structure that facilitates carrier transport. Subsequently, the F element was introduced into the bulk phase of BiOBr using a simple hydrothermal method. The results show that the BiOBr-F photoelectrode exhibits excellent photoelectrocatalysis performance under light and bias voltage. The photocurrent density of the BiOBr-F photoelectrode reached 28.35 μA cm−2 at 1.23 V vs. RHE, which is 2.01 times higher than that of the pure BiOBr, while a negative shift of the onset potential of 119 mV was obtained. The optical absorption tests show that the introduction of the F element forms an impurity energy level thereby extending the optical absorption range of BiOBr. Photoluminescence tests reveal that the introduction of F element effectively restricts the electron-hole pair recombination. This is due tothe fact that the F atoms replace some of the O atoms in BiOBr to create electron traps, thus forming a large number of electron-rich regions in the structure, which in turn reduces the electron-hole pair recombination. This work provides an effective solution to reduce the recombination between carriers by creating electron traps in semiconductor materials through bulk phase doping.

Solution-processed wide band gap transparent conducting Sr0.94La0.06SnO3 films

Pseudo-cubic perovskite La-doped SrSnO3 has been proposed as a promising alternative for ultra-violet (UV) transparent conductors due to its favorable electrical transport properties and UV transparency. However, the difficulty in fabricating large-size La-doped SrSnO3 films with high electrical mobility continues to hinder the development of practical applications. In this work, Sr0.94La0.06SnO3 (SLSO) thin films with wide bandgap of ∼4.5 eV were fabricated by using solution deposition route. Emphasis was placed on creating oxygen-poor environments and selecting appropriate post-annealing temperatures, which were determined based on the kinetic energy of relevant defects and second-phase impurities. Post-annealing treatment was applied to refine the microstructure and enhance electrical transport properties. As a result, a relatively high carrier mobility of 25.9 cm2 V−1 s−1 and a low resistivity of 1.15 mΩ cm at a carrier concentration of 2.08 × 1020 cm−3 were achieved. Enhanced electrical properties were attributed to the increased presence of oxygen vacancies, as confirmed by electron paramagnetic resonance results. This study presents a straightforward approach for the production of large-scale epitaxial UV transparent conducting SLSO thin films.

Enhanced broadband infrared radiation from rare earth orthochromites for High-Temperature radiative heat transfer

The development of broadband, high-performance infrared radiation materials is crucial for energy conservation and applications in aerospace and industrial sectors. Rare earth orthochromites, such as PrCrO3, exhibit good thermal stability and high infrared emissivity beyond the 6 μm wavelength range. However, their large bandgap limits their infrared emissivity before 6 μm, significantly impacting their potential applications. Herein, we have successfully enhanced the thermal emissivity of PrCrO3 by manipulating oxygen vacancies (OV) and accompanying impurity levels, leading to the synthesis of five rare earth orthochromites. Compared with pristine PrCrO3, co-doping of Ca, Co, and Mn introduced oxygen vacancies (OV) and impurity energy levels, effectively reducing the band gap and improving emissivity in the wavelengths below 6 μm. In particular, the infrared emissivity of (Pr0.3Y0.3Ca0.4)CrO3 in the wavelengths of 0.78–2.5 μm reaches 0.89, which is double than that of pristine PrCrO3. Furthermore, its thermal stability is excellent, as demonstrated by thermal shock experiments at 1500 ℃ for five cycles. More importantly, the developed orthochromites can be applied as a coating on substrates such as alumina ceramic sheets, exhibiting an average infrared emissivity of 0.95 and remarkable radiative heat transfer capability. This research contributes to the advancement of high-performance infrared radiation materials by vacancy engineering.

Tailoring electronic structure of stretchable freestanding single-crystal LaNiO3 thin film for enhanced oxygen evolution reaction

The comprehension of the electronic structure of an electrochemical catalyst, as a fundamental core content, has significantly accelerated advancements in competitive catalyst engineering since the adsorption and desorption abilities of an electrode are governed by its surface energy profile. However, achieving precise control over the electronic structure poses a significant challenge. Nanoporous materials, high-entropy systems, and layered double hydroxides frequently induce stoichiometric changes, leading to complexity such as electronic reconstruction, energy degeneracy disruption, and impurity energy levels. Here, we have successfully developed a stretchable freestanding single-crystal LaNiO3 thin film electrocatalyst enabling the accurate manipulation of the electronic structure on a large scale. Different from the rigid epitaxial heterostructure catalyst, we observed that with every 1 % increase in strain, the OER current of freestanding LaNiO3 is enhanced by ∼238 % compared to the pristine state. This is attributed to the dx2-y2 orbital occupation increasing by ∼7 %, and the eg-center decreasing by ∼0.05 eV, resulting in a weakened Ni-O adsorption.