Temperature-dependent Decay Research Articles

Photoluminescence properties of Mn2+-activated red-emitting phosphors with superior thermal stability for backlighting display applications

The red-emitting phosphors, Na2Mg1-x(PO3)4:xMn2+ with concentrations ranging from 0.01 to 0.11, have been successfully synthesized using a simple solid-state method. The as-synthesized phosphors are crystallized in an orthorhombic structure. The luminescence mechanism of Mn2+ ions in Na2Mg(PO3)4 lattice has been deeply explained using the Tanabe-Sugano (T-S) energy level diagram for the d5 electron configuration. The typical photoluminescent emission (PL) and photoluminescent excitation (PLE) spectra were measured. Several excitation peaks in the spectral range of 250–550 nm on the PLE spectrum and a strong emission peak at 613 nm indicate that the as-synthesized phosphors can be effectively excited using ultraviolet (UV) and near-UV LED chips. Several photometric characteristics were measured, such as the Commission International de'LEclarirage (CIE) chromaticity coordinate (x, y), color purity (CP), and correlated color temperature (CCT), corresponding to the concentration-dependent PL spectra. Furthermore, the thermal stability of the Na2Mg1-x(PO3)4:xMn2+ phosphors was investigated through temperature-dependent PL spectra and decay curves from 10 to 500 K. All results confirm that the as-synthesized red-emitting phosphors exhibit excellent thermal stability, which are attractive characteristics for white light emitting diodes (W-LEDs) applications.

Temperature-Dependent Rotation of Protonated Methyl Groups in Otherwise Deuterated Proteins Modulates DEER Distance Distributions

AbstractTemperature-dependent DEER effects are observed as a function of methyl rotation by either leucine- or nitroxide-specific protonated methyl groups in an otherwise deuterated background. Both species induce a site-specific enhancement in the apparent Tm relaxation of the paramagnetic nitroxide label. The presence of a single protonated methyl group in close proximity (4–10 Å) to only one of the two nitroxide rotamer ensembles in AviTagged immunoglobulin-binding B domain of protein A results in a selective and substantial decrease in Tm, manifested by differential decay of the peak intensities in the bimodal P(r) distance distribution as a function of the total dipolar evolution time, temperature, or both. The temperature-dependent differential decay of the individual distance components was globally analyzed by fitting the DEER dipolar time traces to a three-site jump model that is defined by the activation energy of leucine- or nitroxide-specific methyl rotation. Temperature-assisted Tm filtering will capture the DEER structural analysis of biomolecular systems heterogenic conformations, including complexes involving multimeric proteins.

Enhancing Long-Term Water Quality Modeling by Addressing Base Demand, demand Patterns, and Temperature Uncertainty Using Unsupervised Machine Learning Techniques.

Water quality modelling in Water Distribution systems (WDS) is frequently affected by uncertainties in input variables such as base demand and decay constants. When utilizing simulation tools like EPANET, which necessitate exact numerical inputs, these uncertainties can result in inaccurate simulations. This study proposes a novel framework that leverages unsupervised machine learning, specifically a Gaussian Mixture Model (GMMs), to represent and integrate these uncertainties in the simulation. By classifying historical water demand into fuzzy clusters, the framework allows for certain linguistic inputs (e.g., "high" or "low" demand) to be used in water quality simulations. The framework also incorporates representative hourly demand patterns and temperature-dependent chlorine decay constants based on historical data correlations. Validations were conducted on the Anytown network using WNTR-EPANET, comparing simulated chlorine residuals with Validation data from 181 steady-state simulations. The simulation through the framework achieved a Jensen-Shannon Divergence (JSD) of less than 0.008 across all demand clusters, indicating high similarity between predicted and actual probability distributions . In comparison to other simulation scenarios tested, which exhibited increased variability (JSD > 0.18), the proposed framework demonstrated improved accuracy in representing chlorine residual distributions. The methodology is adaptable to other systems, if similar historical datasets containing key variables, such as flow rates and temperature, are provided. While the framework offers a more flexible and accurate approach to handling uncertainties in WDS, its effectiveness is contingent upon the availability of robust historical demand and temperature data for decay constant calibration.

Selecting ns2 electron (Sb3+) and d3 electron (Cr3+) co-doped in lead-free halide double perovskite to achieve blue and near-infrared luminescence

The double-perovskite Cs2NaInCl6 has emerged as a highly favored candidate due to its remarkable stability and eco-friendly properties. However, it is noteworthy that this material does not demonstrate the desired optical performance in the crucial visible and near-infrared (NIR) spectrum, which may limit its potential applications in certain domains. We develop such characteristics in Cs2NaInCl6 by co-doping Sb3+ (s-electron) and Cr3+ (d-electron) ions. Doping with Sb3+ allows for 1S0→3P1 transition absorption, which then emits blue photoluminescence of self-trapped exciton (STE). By co-doping Sb3+ and Cr3+ ions, it causes the transfer of excitation energy from STE to Cr3+, yielding strong NIR emission at 950 nm. Temperature-dependent Photoluminescence (PL), PL excitation, PL decay and Tanabe-Sugano diagram provide insight into photophysical processes. Furthermore, a novel dual-modal optical information encryption based on the integration of blue and NIR luminescence printing patterns using Cs2NaInCl6: Sb3+ and Cs2NaInCl6: Sb3+/Cr3+, respectively, is successfully demonstrated.

Brightening dark excitons in inorganic halide perovskites by local symmetry breaking

Thermally activated delayed fluorescence (TADF) phenomenon, defined as thermal activation of triplet dark-state excitons into singlet state excitons through reverse intersystem crossing (RISC), has become a prevalent principle for designing organic-based electro-/photo-luminescent molecules. However, activating dark excitons in inorganic metal halide perovskites (MHPs) still remains challenging. Herein, we report an efficient strategy of doping-induced local symmetry breaking to brighten dark excitons in inorganic halide perovskite Cs2ZrCl6, which result in a 500 % enhancement of low-temperature luminescence emission. Lattice symmetry breaking confirmed by the X-ray absorption spectroscopy measurements could disturb the local coordination environment at the Zr site. The singlet-triplet energy gap (ΔEST) fitted from temperature-dependent photoluminescence decay curves decreases from 0.087 to 0.071 eV, thus reducing up-conversion barrier of dark excitons. Theoretical calculation indicates large spatial separation of charge density favorable for enhanced TADF emission. Furthermore, a flexible X-ray scintillator screen with poly (dimethylsiloxane) as the matrix could obtain high-quality X-ray imaging with a 14 lp mm−1 resolution. This work gives insights into improving photoemission of inorganic MHPs via brightening dark excitons.

Vehicle routing in precooling logistics with dynamic temperature-dependent product quality decay

This study focuses on precooling operations for post-harvest fruits and vegetables in smallholder countries, aiming to provide an effective way to reduce product losses in the early stage of food supply chains. In this study, we consider the traditional centralized precooling and emerging mobile precooling to fulfill a series of small-scale and scattered precooling requests, with the goal of minimizing the total operating cost while guaranteeing the product quality of farmers. The resulting problem is a variant of the classic heterogeneous fleet vehicle routing problems with time windows, with the additional consideration of heterogeneous service and temperature-dependent product quality decay. The vehicle routing model is formulated by integrating product quality as a constraint in which a dedicated function is developed to capture the quality dynamics under changing temperatures. We design an improved adaptive large neighborhood search method to solve this problem by identifying a strategy that is able to deal with the interactions among decisions. Experiment results quantify the advantages of managing product quality in the early stage of supply chains for perishable products and provide management insights on conducting quality-based precooling services. Numerical experiments based on small-scale instances of the studied problem as well as large-scale benchmark instances verify the effectiveness and efficiency of the proposed algorithm by comparing it with CPLEX and three state-of-the-art algorithms.

Predicting Nonradiative Decay Rate Constants of Cyclometalated Ir(III) Complexes.

The theoretical calculation of the temperature-dependent nonradiative decay rate constant is fundamental for predicting the usefulness of transition-metal complexes for technological applications. Such a computation implies the determination of the barriers separating the emitting triplet state from metal-centered states, which are key mediators of this type of radiationless relaxation. We here do so for the two green-emitting cyclometalated Ir(III) complexes, [Ir(ppy)2(pyim)]+ and [Ir(diFppy)2(dtb-bpy)]+, of general formula [Ir(C∧N)2(N∧N)]+, performing DFT calculations with both B3LYP and PBE0 functionals. On the basis of the obtained results and the comparison with the experimental nonradiative decay rate constants, we conclude that B3LYP provides too low energy barriers to the metal-centered states, while the PBE0 provides reasonable values. We consequently recommend to avoid the use of the commonly employed B3LYP functional for the evaluation of such an energy barrier for cyclometalated Ir(III) complexes.

Optical annealing of peroxo-ferric intermediates in CYP17A1 and product formation.

Human cytochrome P450 CYP17A1 catalyzes the hydroxylation of pregnenolone and progesterone at the C17 position, with subsequent C17-C20 bond scission, to form dehydroepiandrosterone and androstenedione respectively. The first hydroxylation reaction is faster in H2O than in D2O, while the second carbon‑carbon bond scission event demonstrates an inverse solvent isotope effect, which is more pronounced for 17-hydroxy pregnenolone. In order to better understand the cause of this difference, we compared the optical absorption spectra of oxygenated CYP17A1 with the four substrates (pregnenolone, progesterone, 17-hydroxy pregnenolone and 17-hydroxy progesterone) in both H2O and D2O. We also studied the temperature-dependent decay of the peroxo-ferric and hydroperoxo-ferric intermediates generated by cryoradiolysis of the corresponding oxygenated heme proteins at 77 K. For both pregnenolone and 17-hydroxypregnenolone, annealing of the peroxo-intermediates was observed at lower temperatures in H2O than in D2O. In contrast, no solvent isotope effect was detected when progesterone or 17-hydroxyprogesterone were used as substrates. These differences are attributed to their different positioning in the P450 active site with respect to the heme bound peroxo (Fe-OO−) moiety, which is in agreement with earlier structural and spectroscopic investigations. Analysis of the samples run in both H2O and in D2O, where 17-hydroxyprogesterone is the substrate, demonstrated significant (∼25%) yield of androstenedione product relative to the oxygenated starting material.

Ln3+ Induced Thermally Activated Delayed Fluorescence of Chiral Heterometallic Clusters Ln2Ag28.

A series of TADF-active compounds: 0D chiral Ln-Ag(I) clusters L-/D-Ln2Ag28-0D (Ln=Eu/Gd) and 2D chiral Ln-Ag(I) cluster-based frameworks L-/D-Ln2Ag28-2D (Ln=Gd) has been synthesized. Atomic-level structural analysis showed that the chiral Ag(I) cluster units {Ag14S12} in L-/D-Ln2Ag28-0D and L-/D-Ln2Ag28-2D exhibited similar configurations, linked by varying numbers of [Ln(H2O)x]3+ (x=6 for 0D, x=3 for 2D) to form the final target compounds. Temperature-dependent emission spectra and decay lifetimes measurement demonstrated the presence of TADF in L-Ln2Ag28-0D (Ln=Eu/Gd) and L-Gd2Ag28-2D. Experimentally, the remarkable TADF properties primarily originated from {Ag14S12} moieties in these compounds. Notably, {Ag14S12} in L-Eu2Ag28-0D and L-Gd2Ag28-2D displayed higher promote fluorescence rate and shorter TADF decay times than L-Gd2Ag28-0D. Combined with theoretical calculations, it was determined that the TADF behaviors of {Ag14S12} cluster units were induced by 4 f perturbation of Ln3+ ions. Specially, while maintaining ΔE(S1-T1) small enough, it can significantly increase k(S1→S0) and reduce TADF decay time by adjusting the type or number of Ln3+ ions, thus achieving the purpose of improving TADF for cluster-based luminescent materials.

Re-analysis of temperature dependent neutron capture rates and stellar β-decay rates of 95-98Mo

The neutron capture rates and temperature dependent stellar beta decay rates of Mo isotopes are investigated within the framework of the statistical code TALYS v1.96 and the proton neutron quasi particle random phase approximation (pn-QRPA) model. The Maxwellian average cross-section (MACS) and neutron capture rates for the Mo(n,γ) Mo radiative capture process are analyzed within the framework of the statistical code TALYS v1.96 based on the phenomenological nuclear level density model and gamma strength functions. The present model-based computations for the MACS are comparable to the existing measured data. The sensitivity of stellar weak interaction rates to various densities and temperatures is investigated within the framework of the pn-QRPA model. Particular attention is paid to the impact of thermally filled excited states in the decaying nuclei ( Mo) on electron emission and positron capture rates. Furthermore, we compare the neutron capture rates and stellar beta decay rates. It is found that neutron capture rates are higher than stellar beta decay rates at both lower and higher temperatures.

DSFworld: A flexible and precise tool to analyze differential scanning fluorimetry data.

Differential scanning fluorimetry (DSF) is a method to determine the apparent melting temperature (Tma) of a purified protein. In DSF, the raw unfolding curves from which Tma is calculated vary widely in shape and complexity. However, the tools available for calculating Tma are only compatible with the simplest of DSF curves, hindering many otherwise straightforward applications of the technology. To overcome this limitation, we designed new mathematical models for Tma calculation that accommodate common forms of variation in DSF curves, including the number of transitions, the presence of high initial signal, and temperature-dependent signal decay. When tested these models against DSFbase, an open-source database of 6235 raw, real-life DSF curves, these models outperformed the existing standard approaches of sigmoid fitting and maximum of the first derivative. To make these models accessible, we created an open-source software and website, DSFworld (https://gestwickilab.shinyapps.io/dsfworld/). In addition to these improved fitting capabilities, DSFworld also includes features that overcome the practical limitations of many analysis workflows, including automatic reformatting of raw data exported from common qPCR instruments, labeling of data based on experimental variables, and flexible interactive plotting. We hope that DSFworld will enable more streamlined and accurate calculation of Tma values for DSF experiments.

Temperature dependence of photoluminescence kinetics and scintillation properties of LuY2(Al5-xScx)O12:Ce (x = 1, 1.5, 2) garnet single-crystalline films

The temperature dependence of photoluminescence (PL) kinetics and scintillation properties were investigated in LuY2(Al5-xScx)O12:Ce (x = 1, 1.5, 2) garnet single-crystalline films grown by the isothermal liquid phase epitaxy method. With the increase of Sc content, the Ce3+ 5d1 level was shifted to higher energy while the Ce3+ 5d2 level was shifted to lower energy due to the decrease in crystal field splitting of the 5d levels. Activation energy of thermal quenching, determined from temperature-dependent PL decay times, decreased with increasing Sc content. At room temperature, the decrease of light yield (LY) value with increasing Sc content is caused by the thermal ionization process. LuY2(Al4Sc)O12:Ce showed a LY value of 510 photons/MeV when excited by 5.5 MeV α-particles, which is ∼21 % larger than that of Lu2Y(Al4Sc)O12:Ce due to a smaller bandgap Eg of the former.

Ordering kinetics and steady states of XY-model with ferromagnetic and nematic interaction

Previous studies on the generalized XY model have concentrated on the equilibrium phase diagram and the equilibrium nature of distinct phases under varying parameter conditions. We direct our attention towards examining the system’s evolution towards equilibrium states across different parameter values, specifically by varying the relative strengths of ferromagnetic and nematic interactions. We study the kinetics of the system, using the temporal annihilation of defects at varying temperatures and its impact on the coarsening behavior of the system. For both pure polar and pure nematic systems, we observe temperature-dependent decay of the exponent, leading to a decelerated growth of domains within the system. At parameter values where both ferromagnetic and nematic interactions are simultaneously present, we show a phase diagram highlighting three low-temperature phases—polar, nematic, and coexistence—along- side a high-temperature disordered phase. Our study provides valuable insights into the complex interplay of interactions, offering a comprehensive understanding of the system’s behavior during its evolution towards equilibrium.

Ag-CsPbI3 nanocomposite structure in glasses boosts photoluminescence for efficient light emitting diodes

Nanocomposite structures based on perovskite nanocrystals (NCs) and metal nanostructures within transparent monolithic media hold promise for a wide range of applications in optoelectronics. However, the microstructure of such nanocomposites and the reason for enhanced emissions remain incompletely understood. In this work, we present the successful creation of Ag-CsPbI3 nanocomposite within a highly transparent borosilicate glass (Ag-CsPbI3 NCs@glass). We reveal that Ag and CsPbI3 NCs form after thermal treatment of the glass, either in the form of Ag-CsPbI3 heterostructures or of separate Ag and CsPbI3 NCs. Based on combined characterization of Mott-Schottky and steady-state photoluminescence (PL) of the products, we attribute the enhanced PL in the nanocomposite of Ag-CsPbI3 to the regulation of CsPbI3 lattice by Ag ions and/or the plasmonic effect of Ag NCs. Temperature-dependent time-resolved PL decay measurements suggest that Ag NCs could play an important role in the relaxation process of excited carriers by increasing the radiative recombination. Moreover, the Ag-CsPbI3 nanocomposite structure within the glass matrix curtails PL quenching caused by water molecules and high temperature. Using the Ag-CsPbI3 nanocomposite, we achieve high-performance white light-emitting diodes with a color rendering index of 83.9 and luminous efficiency of 58.07 lmW−1. This work elucidates the underlying mechanism on the enhanced PL in nanocomposites containing perovskite NCs and metal nanostructures, and aids in the rational design of glass-based perovskite nanocomposites for a diversity of optoelectronic applications.

Emission enhancement in the luminescence performance of warm red light-emitting LiSrVO4 :Pr3+ phosphors.

Warm red-emitting praseodymium-doped LiSrVO4 phosphors were synthesized via solid-state reaction. The phase formation was verified using an X-ray diffraction study and the morphology was investigated using a scanning electron microscope study. The LiSrVO4 :Pr3+ phosphors emitted red light when exposed to ultraviolet light, indicating their possibility for use in warm white light-emitting diodes (WLEDs). Furthermore, the effect of charge compensators on the luminescence characteristics was addressed. The decay time was investigated using time-resolved photoluminescence. Furthermore, thermal quenching was analyzed through temperature-dependent photoluminescence spectra. Their sensitivity was calculated using temperature-dependent decay time analysis. The colour purity of the emitted light could be measured by photometric analysis. This comprehensive investigation provides a thorough understanding of the luminescence properties of phosphors for WLED applications.

High-performance solar-blind photodetector based on amorphous BN in harsh environment operations

High-performance solar-blind photodetectors capable of operating in extreme environments are desirable for a wide range of applications, such as engine control, down hole drilling, space exploration, and environmental monitoring. Boron nitride (BN), with an ultrawide bandgap and high band edge absorption coefficient, is especially suitable for such application scenarios owing to its chemical and structural stability at high temperatures and radiative conditions, which, however, in turn, brings difficulties in synthesis of large-area continuous single crystalline BN. Here, we report highly robust solar-blind photodetectors based on amorphous BN (a-BN) films that can operate at high temperatures and high electric fields. The a-BN films are dense and uniform, grown at 500 °C using dual beam-assisted deposition method. The a-BN-based photodetectors exhibit high performance with a responsivity of 0.56 mA/W at 20 V under UV illumination of 222 nm and a high rejection ratio (R222 nm/R295 nm > 200 and R222 nm/R315 nm > 500). More importantly, these photodetectors demonstrate excellent responsivity and stability at high temperatures up to 500 K and high bias of 200 V without breakdown. The photocurrent mechanism at elevated temperatures is analyzed by temperature-dependent decay time of the temporal response, showing the electron–phonon interaction and self-trapped holes are dominant. Our work suggests that the deposition of such a-BN films offers a promising strategy toward highly environment-resistant solar-blind photodetectors.

Local Structure and Speciation-Driven UO22+ → Sm3+ Energy Transfer for Enhanced Luminescence in Li2B4O7.

Herein, we report the uranyl sensitization of Sm3+ emissions in uranium-codoped Li2B4O7:Sm3+ phosphor. The uranyl speciation in codoped [Sm, U] LTB samples was determined by synchrotron-based extended X-ray absorption fine structure (EXAFS) spectroscopy that revealed two coordination shells for U(VI) ions with bond distances of U-Oax (∼1.81 Å) and U-Oeq (∼2.30 Å). EXAFS fitting suggested that the uranyl moiety is present as pentagonal bipyramids (UO7) and hexagonal bipyramids (UO8) with five and six equatorial oxygen ligands, respectively. The alteration of the local structure of Sm3+ from [SmO4] to [SmO7] polyhedra and the changes in the coordination number of equatorial oxygen for uranyl were observed with different codoping concentrations of Sm3+ and uranium. Density functional theory (DFT) calculations suggested the lowering of defect formation energy for Li vacancies on codoping of Sm and U. Hence, we proposed the increase of the equatorial coordination number of UO22+ on the increase in the lithium vacancies in LTB. In addition, DFT supported the feasibility of efficient energy transfer (ET) due to the overlap of uranium and Sm3+ excited state levels. The influence of the same on the spectral features and UO22+ → Sm3+ energy transfer was investigated by time-resolved photoluminescence (PL) studies. The ET efficiency from the UO22+ to Sm3+ was 70.5% in 0.5 mol % codoped [Sm, U] LTB samples. The correlation of EXAFS and luminescence properties indicated a red shift in vibronic features of uranyl emission with increase in the equatorial coordination of the uranyl moiety from five to six. Additionally, a higher probability of ET was observed for uranyl speciation as UO8 hexagonal bipyramids. Temperature-dependent emissions and decay profiles were collected under uranyl excitation to investigate the thermal dependence of ET. A high energy barrier (Ea ∼ 4027 cm-1) was evaluated for the thermal quenching of Sm3+ emissions. This work provides insights into the modulation of luminescence and ET efficiency via structural changes in uranyl and Sm local environment in LTB phosphor.

Scintillation and Optical Characterization of CsCu2I3 Single Crystals from 10 to 400 K.

Currently only Eu2+-based scintillators have approached the light yield needed to improve the 2% energy resolution at 662 keV of LaBr3:Ce3+,Sr2+. Their major limitation, however, is the significant self-absorption due to Eu2+. CsCu2I3 is an interesting new small band gap scintillator. It is nonhygroscopic and nontoxic, melts congruently, and has an extremely low afterglow, a density of 5.01 g/cm3, and an effective atomic number of 50.6. It shows self-trapped exciton emission at room temperature. The large Stokes shift of this emission ensures that this material is not sensitive to self-absorption, tackling one of the major problems of Eu2+-based scintillators. An avalanche photo diode, whose optimal detection efficiency matches the 570 nm mean emission wavelength of CsCu2I3, was used to measure pulse height spectra. From the latter, a light yield of 36 000 photons/MeV and energy resolution of 4.82% were obtained. The scintillation proportionality of CsCu2I3 was found to be on par with that of SrI2:Eu2+. Based on temperature-dependent emission and decay measurements, it was demonstrated that CsCu2I3 emission is already about 50% quenched at room temperature. Using temperature-dependent pulse height measurements, it is shown that the light yield can be increased up to 60 000 photons/MeV by cooling to 200 K, experimentally demonstrating the scintillation potential of CsCu2I3. Below this temperature, the light yield starts to decrease, which can be linked to the unusually large increase in the band gap energy of CsCu2I3.

Sensing performance of β-Ga2O3 metal–semiconductor-metal deep ultraviolet photodetectors with refractory TiW electrodes at high temperatures

Given the critical impact of high-temperature environments on the detection performance and stability of deep ultraviolet (DUV) photonic devices, especially in urgent demands from fields including high-temperature industries and flame detection, the research on high-temperature resistant DUV photodetectors (PDs) has become of utmost importance. Due to its intrinsic high-temperature resistance, β-Ga2O3 holds significant potential in the field of DUV photodetection under elevated temperature environments. The conventional electrode material, titanium, typically exhibits poor high-temperature performance, while interfaces are susceptible to degradation at elevated temperatures. In this study, we fabricated β-Ga2O3 metal–semiconductor-metal (MSM) PDs using the refractory metal TiW as the electrode, and investigated their DUV detection performance across the temperature range of 300 to 800 K. Favorable performance was achieved at room temperature, with a photo-to-dark current ratio (PDCR) of 3.1 × 106, a responsivity (R) of 0.2 A/W, a detectivity (D*) of 8.3 × 1013 Jones, and an external quantum efficiency (EQE) of 102.3 %. However, an increase in operating temperature led to a continuous rise in dark current (Idark) and a decrease followed by an increase in photocurrent (Iphoto). In an 800 K operating environment, the PDCR decreased to 4.4 × 102, R increased to 0.7 A/W, D* dropped to 2.0 × 1012 Jones, and EQE improved to 343.7 %. Furthermore, the temperature-dependent rise and decay times were investigated, and a detailed analysis of the relevant recombination and transport mechanisms under high-temperature conditions was conducted. By achieving high-performance and stable operation of β-Ga2O3 PDs at 800 K, this study provides prospects for the application of β-Ga2O3 PDs in harsh environments.

Boosting the Self-Trapped Exciton Emission in Cs4SnBr6 Zero-Dimensional Perovskite via Rapid Heat Treatment.

Zero-dimensional (0D) tin halide perovskites feature extraordinary properties, such as broadband emission, high photoluminescence quantum yield, and self-absorption-free characteristics. The innovation of synthesis approaches for high-quality 0D tin halide perovskites has facilitated the flourishing development of perovskite-based optoelectronic devices in recent years. However, discovering an effective strategy to further enhance their emission efficiency remains a considerable challenge. Herein, we report a unique strategy employing rapid heat treatment to attain efficient self-trapped exciton (STE) emission in Cs4SnBr6 zero-dimensional perovskite. Compared to the pristine Cs4SnBr6, rapid thermal treatment (RTT) at 200 °C for a duration of 120 s results in an augmented STE emission with the photoluminescence (PL) quantum yield rising from an initial 50.1% to a substantial 64.7%. Temperature-dependent PL spectra analysis, Raman spectra, and PL decay traces reveal that the PL improvement is attributed to the appropriate electron-phonon coupling as well as the increased binding energies of STEs induced by the RTT. Our findings open up a new avenue for efficient luminescent 0D tin-halide perovskites toward the development of efficient optoelectronic devices based on 0D perovskites.