Multiple-emission phosphors, which can be engineered via co-doping strategies and energy transfer regulation, have become a research hotspot in recent years. In this research, Mn2+ and Cr3+ doped Sr2MgAl22O36 phosphors were prepared using a high-temperature solid-state reaction method. The green light emission of Mn2+ and the deep-red emission of Cr3+ were investigated, and the impacts of doping concentration and temperature were discussed in detail. Dual-band emission can be achieved for co-doped samples under blue light excitation, and the energy transfer from Mn2+ to Cr3+ was confirmed. Owing to the distinct temperature responses of Mn2+ and Cr3+, optical temperature sensing properties were demonstrated for the co-doped sample, which may offer a feasible approach for non-contact temperature measurement. Moreover, a triple-emission phosphor-converted light-emitting diode (pc-LED) device was fabricated, highlighting the potential application of Sr2MgAl22O36:Mn2+,Cr3+ in plant growth.

Achieving thickness-controlled perovskite microplates via chemical vapor deposition (CVD) is an effective approach to enhancing cavity optical feedback, which is crucial for realizing ultralow-threshold continuous-wave (CW) perovskite lasers. Here, we report the thickness-controlled synthesis of CsPbBr3 films/microplates via SnBr2-regulated crystallization by single-step CVD. The introduction of low-melting-point SnBr2 has assisted controllable crystallization dynamics of CsPbBr3 by inhibiting the chemical reaction process between CsBr and PbBr2, thereby optimizing nucleation density and crystal growth rate. The precise control of SnBr2 not only reduces the deposition rate and promotes grain growth in CsPbBr3 films/microplates, but also eliminates defect states within these structures. The resulting CsPbBr3 microplates possess high crystal quality and strong photoluminescence, while maintaining stability under continuous CW-laser illumination without observable photodegradation. Consequently, we achieved stable multi-mode whispering-gallery mode lasing with a low threshold of 153 W/cm2 under 405-nm laser excitation at room temperature. Our findings will open up multiple avenues for the design and fabrication of high-quality perovskites micro-crystals for CW-pumped perovskite lasers.

Zero-dimensional (0D) tin halide perovskites have emerged as promising luminescent materials owing to their broadband emission, high quantum yield, and negligible self-absorption. Yet, their luminescence efficiency and stability remain insufficient for practical optoelectronic applications. Here, Sb3+ dopants are introduced into Cs4SnBr6 through a water-assisted wet ball milling strategy, resulting in bright and thermally robust emission. The doped materials exhibit pronounced self-trapped exciton (STE) luminescence centered at 525 nm with a broad full width at half maximum of 110 nm, a large Stokes shift of approximately ~1.3 eV, and a photoluminescence lifetime of ~0.8 µs. Remarkably, Sb3+ incorporation boosts the photoluminescence quantum yield (PLQY) up to 64% at room temperature while simultaneously improving thermal stability. Correlated spectroscopic analyses reveal that the Sb3+-induced lattice distortion of the [SnBr6]4− octahedra strengthens electron–phonon interactions and elevates the STE binding energy, thereby stabilizing the excited states and suppressing nonradiative losses.

To develop a novel type of white-light-emitting phosphor, we successfully prepared a series of Ce3+/Eu2+/Sm3+ activated color-tunable phosphor Sr8MgY(PO4)7 (SMYP) through a classical solid-state reaction and crystal structure, luminescent characteristic, energy transfer and systematically investigated thermal stability of assynthesized samples. The results manifest that the phase purity of Ce3+/Eu2+/Sm3+ co-doped SMYP phosphors was verified by the Rietveld structure refinements. Under 315 nm ultraviolet (UV) excitation, the Ce3+ single-doped SMYP phosphor reveals a broad and strong bluish-violet emission band in the range of 325-480 nm. The outstanding enhancement of Eu2+ emission intensity is realized by Ce3+ induced resonance energy transfer (ET). The ET mechanism of Ce3+-> Eu2+ is governed by an electronic quadrupole-quadrupole interaction with a high ET efficiency of 89.8 %. In addition, the luminescent color of SMYP: Ce3+/Eu2+ samples can be changed from light green to white by introducing activators Sm3+ ions. The optimal chromaticity coordinate could be adjusted to (0.311, 0.343), which is the closest to the ideal white light coordinate (0.330, 0.330). To achieve white light, a white LED device fabricated by combining a 310 nm chip with the SMYP: Ce3+/Eu2+/Sm3+ phosphor shows a high color rendering index (CRI = 87.2) along with a low correlated color temperature (CCT approximate to 4056.7 K) under the stimulation of 5 V voltage and 100 mA current. The above results show that SMYP: Ce3+/Eu2+/Sm3+ as a single component phosphor has potential application prospects in UV-pumped full-spectrum white LEDs.

Tin (Sn)-based perovskites show significant potential in lead-free perovskite optoelectronics. Currently, the spin-coating method combining DMSO co-solvent and antisolvent-dropping has been adopted to produce Sn-based perovskite films. However, DMSO intrinsically oxidizes Sn2+ while fast antisolvent-dropping causes serious coupling between crystal nucleation and growth, leading to the easy formation of defects and poor stability of Sn-based perovskite films. Herein, hydrazine acetate (HAAc) ionic salt, possessing strong coordination ability with Sn2+, is developed to stabilize Sn2+ and decouple the crystallization by promoting pre-formed crystals (PFCs) in precursor solution and enabling the self-assembly of PFCs during spin-coating. The HAxFA1-xSnI3 films fabricated by this PFCs self-assembly technique show tunable bandgap, low defect density, and oriented crystals, producing optoelectronic devices with decent photovoltaic and electroluminescence performance. The DMSO-free one-step film-forming enabled by HAAc-assisted crystallization decoupling can open up new avenues for facile and low-cost manufacturing of efficient and stable optoelectronic devices adopting Sn-based perovskite films.

As an ideal eco-friendly Pb-free optoelectronic material, Sn-based perovskites have made significant progress in the field of photovoltaics, and the highest power conversion efficiency (PCE) of Sn-based perovskite solar cells (PSCs) has been currently approaching 16%. In the course of development, various strategies have been proposed to improve the PCE and stability of Sn-based PSCs by solving the inherent problems of Sn2+, including high Lewis acidity and easy oxidation. Notably, the recent breakthrough comes from the development of heteroatomic coordination molecules to control the characteristics of Sn-based perovskites, which are considered to be vital for realizing efficient PSCs. In this review, the up-to-date advances in the design of heteroatomic molecules and their key functions in the fabrication of Sn-based perovskite films are comprehensively summarized. Firstly, the design principles of heteroatomic coordination molecules and their impact on the colloidal chemistry, crystallization dynamics, and defect properties of Sn-based perovskites are introduced. Then, state-of-the-art heteroatomic coordination molecules for efficient Sn-based PSCs are discussed in terms of their heteroatom types and functional groups. Lastly, we shed some light on the current challenges and future perspectives regarding the rational design of heteroatomic coordination molecules for further boosting the performance of Sn-based PSCs.

Hydraulic fracturing then fluid circulation in enhanced geothermal system (EGS) reservoirs have been shown to induce seismicity remote from the stimulation-potentially generated by the distal projection of thermoporoelastic stresses. We explore this phenomenon by evaluating stress perturbations resulting from stimulation of a single stage of hydraulic fracturing that is followed by thermal depletion of a prismatic zone adjacent to the hydraulic fracture. We use Coulomb failure stress to assess the effect of resulting stress perturbations on instability on adjacent critically-stressed faults. Results show that hydraulic fracturing in a single stage is capable of creating stress perturbations at distances to 1000 m that reach 10-5-10-4 MPa. At a closer distance, the magnitude of stress perturbations increases even further. The stress perturbation induced by temperature depletion could also reach 10-3-10-2 MPa within 1000 m-much higher than that by hydraulic fracturing. Considering that a critical change in Coulomb failure stress for fault instability is 10-2 MPa, a single stage of hydraulic fracturing and thermal draw-down are capable of reactivating critically-stressed faults at distances within 200 m and 1000 m, respectively. These results have important implications for understanding the distribution and magnitudes of stress perturbations driven by thermoporoelastic effects and the associated seismicity during the simulation and early production of EGS reservoirs. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

The chemical identity of oxygen species plays a decisive role in determining the optical stability of halide perovskite QD films. Here, real-time in situ spectroscopic monitoring, together with steady-state and time-resolved photoluminescence measurements, is utilized to differentiate the effects of molecular oxygen and plasma-activated oxygen species on CsPbBr3 QD films. The films maintain nearly unchanged emission intensity, spectral profile, and carrier lifetimes when stored in vacuum or exposed to molecular O2 even under UV illumination, demonstrating that neutral O2 exhibits minimal reactivity toward the [PbBr6]4- framework. In contrast, oxygen plasma generates highly reactive atomic and ionic oxygen species that induce rapid and spatially heterogeneous photoluminescence quenching. This degradation is attributed to Br- extraction, Br-vacancy formation, and subsequent Pb-O bond generation, which collectively introduce deep trap states and enhance nonradiative recombination. These findings clearly indicate that reactive oxygen species rather than molecular O2 are the dominant driver of oxygen-induced luminescence degradation, providing mechanistic insight and offering processing guidelines for the reliable integration of perovskite nanomaterials in optoelectronic devices.

The southeastern Sichuan basin possesses abundant gas shale resources that are currently being recovered. The basement strata are seismically active making it important to understand the effect of fluid injection during geoenergy extraction and storage. We recovered outcropping basement rocks and conducted friction experiments on simulated rock gouge to assess the potential for frictional stability. Meanwhile, we also calculated the poroelastic Coulomb stresses resulting from fluid injection to define the impact of stress perturbations on fault stability. These results are combined with the seismic reflection images to analyze the seismic potential. Results indicate the basement rocks include clay-lean granites and sandstones and clay-rich slates; gouge frictional strength and stability are controlled by the clay contents. The gouge frictional strength monotonically decreases and fault stability is enhanced with increasing clay content. Poroelastic stresses induced by fluid injection can reactivate critically-stressed faults within 2 km of the injection site, but decay rapidly with increasing distance. The experimental-modelling results combined with seismic reflection profiles indicate that basement fault stability is controlled by various factors, including fault aseismic slip in the pressurized zones, poroelastic stress transfer from fluid injection and gouge mineralogy. These results have important implications for understanding instability of basement faults induced by fluid injection during energy extraction and storage and contribute to reducing seismic hazard in the southeastern Sichuan basin.

Tin (Sn)-based perovskite solar cells (TPSCs) have garnered significant attention recently, with power conversion efficiencies (PCEs) approaching 16%. Nevertheless, for Sn-based perovskites, their rapid crystallization and easy Sn2+ oxidation are always annoying for fabricating efficient and stable TPSCs. Coordination engineering has been developed for retarding the crystallization rate and Sn2+ passivation, but the homogeneous crystallization of Sn-based perovskites is still challenging due to the asymmetric and polar nature of currently used ligands. Here, a polarity-free S-containing symmetric molecule, 1,3,5-trithiane (TT), is developed to regulate the crystallization of FASnI3. Nonpolar TT with three symmetric S atoms shows equally strong coordination with Sn2+, which enhances the environment stability of the precursor and promotes the homogeneous nucleation and retarded growth of FASnI3 crystals. Consequently, TT-based TPSCs exhibit an improved PCE from 9.02% to 12.87% with robust stability. This study highlights the critical role of ligand polarity in controlling the crystallization behavior of efficient TPSCs.

As the societal demand for innovative talents continues to soar, the cultivation of these individuals has become a crucial mandate for undergraduate institutions in China. This study addresses the lack of systematic, in-depth, and targeted approaches to nurture innovative talents in the Materials specialty at local undergraduate institutions in China. Focusing on undergraduate students studying Materials at the authors’ esteemed institution, a “three-stage progressive” training reform and practice were implemented to foster innovative talents in this discipline. The outcomes of this endeavor demonstrate a noticeable enhancement in students’ innovative prowess and creative capacities compared to the previous methods, while educators have exhibited significant advancements in their abilities to impart knowledge on innovation and entrepreneurship. This study serves as a paradigmatic framework and a point of reference for cultivating innovative talents in the realm of materials at local Chinese universities.

ABSTRACT: Epidote and chlorite are both low-grade metamorphic minerals that are widely distributed in deep granite geothermal reservoirs. Hot fluid circulation promotes the precipitation of epidote and chlorite coatings on natural faults and fractures and this can in turn exert control on fault/fracture frictional stability. We use simulated epidote/chlorite gouges and conduct fault shear experiments at conditions typifying the ∼4 km depth typical of deep geothermal reservoirs to explore the effect of epidote/chlorite content on frictional strength and stability. Results indicate that the frictional characteristics of epidote and chlorite gouges vastly differ. Epidote gouge is frictionally strong, with a coefficient of friction of ∼0.73, nearly double that of the chlorite gouge (∼0.35). In addition, the epidote gouge exhibits strong velocity-weakening and unstable frictional behavior under the test conditions, while the chlorite gouge is velocity-strengthening and stable. Fault frictional strength and velocity-weakening behavior are all enhanced for epidote-granite mixed gouges as epidote content increases. However, chlorite-granite mixed gouges show the opposite trend with increasing chlorite content. Our results have important implications in understanding the frictional stability of epidote/chlorite-filled granite faults and its influence on seismicity in deep geothermal reservoirs inhabiting the shallow crust. 1. INTRODUCTION The moment magnitude (Mw) 5.5 Pohang earthquake that occurred in November 2017 has been demonstrated as one of the largest and most damaging earthquakes on the Korean peninsula since the last century (Grigoli et al., 2018; Kim et al., 2018). This event has attracted widespread attention not only for the significant resulting hazard and damage but also due to its connection with the Pohang Enhanced Geothermal System (EGS) project in South Korea. This earthquake (Lee et al., 2019a) directly injured >100 people and resulted in >US$300 million in economic loss, and it is also the largest known injection-induced earthquake at an EGS site. Currently, it has been confirmed that an unmapped pre-existing critically-stressed fault was reactivated at a depth of ∼4.0 km by the fluid injection during EGS stimulation and finally trigger the seismicity (Lee et al., 2019a).

The prompt detection of toxic gases like CO, NO2, C2H2, and C2H4 is crucial for both environmental preservation and industrial safety. In this work, we investigate the adsorption behavior and sensing performance of these four gases on both intrinsic g-CN and g-CN modified with single Pd atom and Pd-B pair, denoted as Pd-g-CN and Pd-B-g-CN, respectively, utilizing the first-principles calculations. The results indicate that the introduction of Pd atom and Pd-B pair significantly enhances the adsorption effect of g-CN monolayer toward these gases, with adsorption energies ranging from - 0.44 eV to - 1.43 eV. Furthermore, all adsorptions are identified as chemisorption, with the adsorption strength following the order of NO2 > CO > C2H4 > C2H2. Additionally, the adsorption of NO2, C2H2, and C2H4 induces notable changes in the work function of Pd-g-CN and Pd-B-g-CN, as well as approximately a 20-time increase in the bandgap of Pd-g-CN. Moreover, the Pd-g-CN and Pd-B-g-CN monolayers exhibit reasonable recovery times for C2H2 and C2H4, measured as 0.04 s and 6.40 mu s at 298 K, respectively. Furthermore, NO2 can be rapidly desorbed from the Pd-B-g-CN surface at 398 K, with a short recovery time of 8.17 s. Therefore, the Pd-g-CN and Pd-B-g-CN monolayers can be regarded as potential gas-sensitive materials for the detection of C2H2 and C2H4 at room temperature, respectively. These research findings provide robust theoretical support for the design of novel gas sensors and efficient toxic gas adsorbents.

Understanding the volume expansion behavior of Si anodes and their interaction with electrolyte environments is crucial for developing high-performance lithium-ion batteries (LIBs). This study utilizes a graphene liquid cell for in situ imaging to systematically investigate the volume expansion and etching behavior of Si anode nanoparticles in different electrolyte environments. Comparative experiments on Si@C core-shell nanoparticles assess their volume expansion dynamics. The findings reveal significant variation in the expansion rate of nano Si depending on the electrolyte environment, with chemical etching observed under specific conditions. Conversely, Si@C core-shell structures show mitigated expansion due to the confinement effect of the carbon matrix. Battery performance experiments validate these results, demonstrating the excellent cycling stability of Si@C anodes. Various coating agents are explored to optimize Si@C structures, with dopamine thin layer coating exhibiting the best cycling stability. This study offers fundamental insights into Si anode expansion, electrolyte effects, and carbon coating impacts, advancing LIB technology.

Recently, a novel MoSi2N4 monolayer has been successfully synthesized (Science 369, 670, 2020) and exhibits excellent photoelectric property. Motivated by this, the adsorption characteristics and sensing properties of four toxic gases (CO, NO, NO2, SO2) on the Pd and Ag doped MoSi2N4 (Pd-MSN and Ag-MSN) monolayers were systematically investigated by DFT computations, which aims to explore their feasibility as a potential gas-sensitive material. The studied results show that the Pd-MSN and Ag-MSN monolayers possess high stability due to the large binding strength. The SO2 molecule is physically adsorbed on the Pd-MSN and Ag-MSN surface with E-ads of -0.43 and -0.45 eV. However, the chemisorption of CO, NO, NO2 on the surface can be found with the E-ads of -0.73 eV similar to -1.24 eV, and the strong surface bonding force is mainly contributed by the significant hybridizations between N-p orbital of Pd/Ag-MSN and p orbitals of CO, NO, NO2. Moreover, the Pd-MSN and Ag-MSN monolayers are highly sensitive to CO and NO molecules due to their great change in electrical conductivity and work function. Additionally, the recovery time of NO and CO in Pd-MSN system is respectively predicted to be 0.03 and 0.12 s at room temperature, whereas the rapid desorption of NO and CO from Ag-MSN surface requires the help of high temperature. Therefore, the Pd-MSN monolayer can be a promising gas-sensitive material with excellent sensitivity for the detection of CO and NO. Those studied results can provide a theoretical guidance for the designing of MoSi2N4 based gas sensors.

In this study, a series of well-crystallized Yb3+/Er3+/Tm3+-tridoped Y2O3-ZnO ceramic nano-phosphors were prepared using sol–gel synthesis, and the phosphor structures were studied using X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The phosphors were well crystallized and exhibited a sharp-edged angular crystal structure and mesoporous structure consisting of 270 nm nano-particles. All phosphors generated blue, green, and red emission bands attributed to Tm: 1G4→3H6, Er: 2H11/2 (4S3/2)→4I15/2, and Er: 4F9/2→4I15/2 radiative transitions, respectively. Increasing in luminescent centers, weakening of lattice symmetry, and releasing of dormant rare earth ions can enhance all emissions. Er3+ can obtain energy from Tm3+ to enhance green and red emission. These colors can be tuned by optimizing the doping concentrations of the Er3+ ion. The color coordinates were adjusted by tuning both the Er3+ concentration and excitation laser pump power to shift the color coordinates and correlated color temperature. The findings of this study will broaden the potential practical applications of phosphors.

The photoluminescence (PL) from carbon dots can be dramatically modified through the engineering of surface oxygen-containing functional groups. Despite the recent surge of interest in the non-metal doping of carbon dots, the photo-physical properties of metal-doped carbon dots remain unexplored. Here, we report the highly efficient deep blue PL and amplified spontaneous emission from sodium (Na)-ion-doped carbon dots. Based on the structure- and temperature-dependent PL and the temporal evolution of PL, we reveal that the introduction of Na ions into carbon dots not only passivate the electronegative oxygen related defects but also create new Na-O related defect centers in the band gap, leading to deep blue PL with dramatically reduced bandwidth and significantly enhanced quantum yield. We establish a luminescence model with four energy levels to interpret the PL dynamics of Na+-doped carbon dots. We demonstrate for the first time the ASE from such carbon dots, which exhibit a net optical gain coefficient of 47.8 cm-1 at 440 nm. Our results open new horizons for improving the PL of carbon dots and pave the way for realizing optoelectronic devices based on carbon dots.

The enhanced red photoluminescence (PL) from Si-rich amorphous silicon carbide (a-SiCx) films was analyzed in this study using nitrogen doping. The increase in nitrogen doping concentration in films results in the significant enhancement of PL intensity by more than three times. The structure and bonding configuration of films were investigated using Raman and Fourier transform infrared absorption spectroscopies, respectively. The PL and analysis results of bonding configurations of films suggested that the enhancement of red PL is mainly caused by the reduction in nonradiative recombination centers as a result of the weak Si–Si bonds substituted by Si–N bonds.

In this paper, K+ ion-doped Y2O3: Yb3+/Er3+ luminescent films were prepared using the sol-gel method. The structures of the films were studied using X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy. A series of high-quality thin films with good crystallization were prepared. The effect of K+ ion doping on the light emission of the samples was investigated. With increasing K+ doping concentration, initially, the lattice was compressed and then stretched. For the undoped samples, the main light emission bands were green and red emissions attributed to Er3+: 2H11/2(4S3/2) -> 4I15/2 and Er3+: 4F9/2 -> 4I15/2, respectively, both of which are two-photon processes, accompanied by weak purple emission attributed to Er3+: 2G7/2 -> 4I15/2, which is a three-photon process. Compared with the undoped sample, the emission attributed to three-photon process may be eliminated by using K+ doping, and the green and red emission intensity may be increased by factors of 2.39 and 2.51 with increasing K+ ion doping, respectively. With the increase in K+ ion doping, the changes in active luminescent centers and distance between rare earth ions were analyzed, and the effect of the process energy transfer (ET) process and cross relaxation (CR) attributed to those on light emission was discussed.