Narrow Emission Research Articles

Cost-Effective Approach for Modeling of Multiresonant Thermally Activated Delayed Fluorescence Emitters.

Multiresonant thermally activated delayed fluorescence (MR-TADF) emitters have recently attracted great interest for application in organic light-emitting diodes due to their remarkable electroluminescent efficiency and narrow emission spectra. It is therefore essential to establish computational methodologies that can accurately model the excited states of these materials at manageable computational costs. With regard to MR-TADF design and their associated photophysics, previous works have highlighted the importance of wave function-based methods, at much higher computational costs, over the traditional time-dependent density functional theory approach. Herein, we employ two independent techniques built on different quantum mechanical frameworks, highly correlated wave function-based STEOM-DLPNO-CCSD and range-separated double hybrid density functional, TD-B2PLYP, to investigate their performance in predicting the excited state energies in MR-TADF emitters. We demonstrate a remarkable mean absolute deviation (MAD) of ∼0.06 eV in predicting ΔEST compared to experimental measurements across a large pool of chemically diverse MR-TADF molecules. Furthermore, both methods yield superior MAD in estimating S1 and T1 energies over earlier reported SCS-CC2 computed values [J. Chem. Theory Comput. 2022, 18, 4903]. The short-range charge-transfer nature of low-lying excited states and narrow fwhm values, hallmarks of this class of emitters, are precisely captured by both approaches. Finally, we show the transferability and robustness of these methods in estimating rates of radiative and nonradiative events with adequate agreement against experimental measurements. Implementing these cost-effective computational approaches is poised to streamline the identification and evaluation of potential MR-TADF emitters, significantly reducing the reliance on costly laboratory synthesis and characterization processes.

Exploiting the Photo-Physical Properties of Metal Halide Perovskite Nanocrystals for Bioimaging.

Perovskite nanomaterials have recently been exploited for bioimaging applications due to their unique photo-physical properties, including high absorbance, good photostability, narrow emissions, and nonlinear optical properties. These attributes outperform conventional fluorescent materials such as organic dyes and metal chalcogenide quantum dots and endow them with the potential to reshape a wide array of bioimaging modalities. Yet, their full potential necessitates a deep grasp of their structure-attribute relationship and strategies for enhancing water stability through surface engineering for meeting the stringent and unique requirements of each individual imaging modality. This review delves into this evolving frontier, highlighting how their distinctive photo-physical properties can be leveraged and optimized for various bioimaging modalities, including visible light imaging, near-infrared imaging, and super-resolution imaging.

Constructing Multiresonance Thermally Activated Delayed Fluorescence Emitters for Organic LEDs: A Computational Investigation.

Multiple resonance thermally activated delayed fluorescence (MR-TADF) materials have acquired substantial attention due to their high electroluminescence efficiency with narrow emission spectra. However, the existing MR-TADF emitters suffer from substantial efficiency roll-off due to insufficient rate constants of the reverse intersystem crossing (kRISC) process compared to the traditional TADF materials. Herein, we employ the DLPNO-STEOM-CCSD method, which is computationally less expensive than the wave function-based EOM-CCSD method, to evaluate the electronic and photophysical properties of MR-TADF materials accurately. The predicted singlet-triplet energy gap (ΔEST), one of the critical parameters governing the TADF efficiency, exhibits remarkable agreement with the experimental measurement, with a standard deviation value of 0.026 eV (obtained based on five experimentally synthesized MR-TADF systems). The proposed technique was utilized to determine the suitability of 15 newly designed MR-TADF emitters via their computed radiative and nonradiative rates, luminescence efficiencies, and exciton characteristics. Moreover, most conceived molecules exhibit blue emission with decent to strong oscillator strengths, making them potential candidates for practical light-emitting applications. The proposed computational route will undoubtedly accelerate the designing and prescreening of potential MR-TADF emitters before their expensive laboratory synthesis and characterization.

Order and Disorder in Mixed (Si, P)–N Networks Sr2SiP2N6:Eu2+ and Sr5Si2P6N16:Eu2+

AbstractIn the field of nitride phosphors, which are crucial for phosphor‐converted light‐emitting diodes, mixed tetrahedral networks hold a significant position. With respect to the wide range of compositions, the largely unexplored (Si, P)–N networks are investigated as potential host structures. In this work, two highly condensed structures, namely Sr2SiP2N6 and Sr5Si2P6N16 are reported to address the challenges that arise from the similarities of the network‐forming cations Si4+ and P5+ in terms of charge, ionic radius, and atomic scattering factor, a multistep workflow is employed to elucidate their structure. Using single‐crystal X‐ray diffraction, energy‐dispersive X‐ray spectroscopy (EDX), atomic‐resolution scanning transmission electron microscopy (STEM)‐EDX maps, and straightforward crystallographic calculations, it is found that Sr2SiP2N6 is the first ordered, and Sr5Si2P6N16 the first disordered, anionic tetrahedral (Si, P)–N network. After doping with Eu2+, Sr2SiP2N6:Eu2+ shows narrow cyan emission (λmax = 506 nm, fwhm = 60 nm/2311 cm−1), while for Sr5Si2P6N16:Eu2+ a broad emission with three maxima at 534, 662, and 745 nm upon irradiation with ultraviolet light is observed. An assignment of Sr sites as probable positions for Eu2+ and their relation to the emission bands of Sr5Si2P6N16:Eu2+ is discussed.

Mn5+-doped BaAl2O4, Ba3Al2O6, and Ba7Al2O10 phosphors emitting in the second near-infrared biological window

In recent years, NIR-II-type fluorophores with emission wavelengths within the 1000–1700 nm range have garnered widespread attention in the field of bioimaging due to their high tissue penetration ability. Here, Mn-doped BaAl2O4, Ba3Al2O6, and Ba7Al2O10 with NIR-II-type luminescence were synthesized by solid-phase or liquid-phase methods. Confirmed by XPS and EDS analysis, Mn is found uniformly distributed in the structure in the valence state of + 5. The optimal doping concentration of Mn5+ in the three matrices was analyzed by PLE and PL spectroscopy. In addition, the samples exhibit a wide excitation range spanning from 600 to 900 nm, coupled with a narrow emission band peaking between 1150 and 1200 nm. As both the excitation and emission wavelengths have excellent penetration capabilities in biological tissues, the synthesized fluorescent phosphors in this study hold potential for meaningful applications in the realm of fluorescence imaging.

A Review of in vivo Toxicity of Quantum Dots in Animal Models.

Tremendous research efforts have been devoted to nanoparticles for applications in optoelectronics and biomedicine. Over the past decade, quantum dots (QDs) have become one of the fastest growing areas of research in nanotechnology because of outstanding photophysical properties, including narrow and symmetrical emission spectrum, broad fluorescence excitation spectrum, the tenability of the emission wavelength with the particle size and composition, anti-photobleaching ability and stable fluorescence. These characteristics are suitable for optical imaging, drug delivery and other biomedical applications. Research on QDs toxicology has demonstrated QDs affect or damage the biological system to some extent, and this situation is generally caused by the metal ions and some special properties in QDs, which hinders the further application of QDs in the biomedical field. The toxicological mechanism mainly stems from the release of heavy metal ions and generation of reactive oxygen species (ROS). At the same time, the contact reaction with QDs also cause disorders in organelles and changes in gene expression profiles. In this review, we try to present an overview of the toxicity and related toxicity mechanisms of QDs in different target organs. It is believed that the evaluation of toxicity and the synthesis of environmentally friendly QDs are the primary issues to be addressed for future widespread applications. However, considering the many different types and potential modifications, this review on the potential toxicity of QDs is still not clearly elucidated, and further research is needed on this meaningful topic.

Orange persistent luminescence of LuBaZn3GaO7: Bi3+ phosphor based on defect induction for optical thermometer and multi-mode anti-counterfeiting

In this study, the Bi3+ doped LuBaZn3GaO7 fluorescent powder was produced using a high-temperature solid-state technique, and its long afterglow luminescence and dynamic anti-counterfeiting capabilities were thoroughly examined. Under the ultraviolet (UV) light excitation, the LuBaZn3GaO7 host exhibits broadband self-activated emission band peak at 594 nm, attributed to the O-vacancies. Upon Bi3+ doping, the phosphor produces a narrow emission band in the 350–450 nm wavelength range, which is caused by the 3P1–1S0 transition of the Bi3+ ions in the Ba2+ site. Remarkably, oxygen vacancy-induced electronic localization around the Bi3+ ions increases the emission intensity of LuBaZn3GaO7:0.01Bi3+ around ten times that of LuBaZn3GaO7 between 450 and 850 nm wavelength. With the variation in excitation light wavelength, the intensity of the two emission bands of LuBaZn3GaO7: Bi3+ changed accordingly, exhibiting multi-color luminescence. While the excitation was removed after 3-min irradiation, LuBaZn3GaO7: Bi3+ phosphors continued to emit for 10 min. Moreover, the phosphor emission has good temperature-sensitive characteristics based on the fluorescence intensity ratio (FIR) of the emission bands of Bi3+ ions and host. Hence, an optical thermometry with high-temperature sensitivity was constructed. Consequently, it can be concluded that fluorescent powder has the potential to be applied in the fields of fluorescence temperature measurement and anti-counterfeiting.

Blueshifted Fe ii and Balmer Broad Emission lines in a Reddened Quasar

We present detailed analysis of the optical and near-infrared spectrum of the reddened radio-loud quasar F2M J154043.74+492323.9 with strong optical Fe ii emission of . It is found that the peaks of broad emission lines (BELs), including Hα, Hβ, and Hγ, and the peaks of individual Fe ii BELs, are blueshifted as large as v ≈ 1500 km s−1 with respect to the systemic redshift determined by the low-ionization [O ii] narrow emission line. BEL components at the systemic redshift are also significantly detected, though much weaker than the corresponding blueshifted components. Interestingly, the Mg ii BEL also shows a similar double-peaked profile, yet with a weaker blueshifted component relative to the unshifted one. We interpret these exceptional BELs as originating from massive outflows, possibly with both densities and column densities much higher than those of the normal BEL region (BELR). Alternative scenarios, however, cannot be completely ruled out based on the data available, including a gravitationally bound binary of active supermassive black holes (SMBHs), each with an unattached BELR, or a recoiling SMBH caused by anisotropic gravitational radiation during the coalescence of the progenitor binary. Follow-up observations will be able to disentangle these scenarios, and to also provide valuable clues to understand the growth of SMBHs and the assembly of their host galaxies.

Visible-Light Communication with Lighting: RGB Wavelength Division Multiplexing OLEDs/OPDs Platform.

A multichannel/multicolor visible light communication (VLC) system using entirely organic components, including organic light emitting diodes (OLEDs) and organic photodiodes (OPDs), is developed to demonstrate indoor lighting applications where the integration of OLEDs and OPDs has significant potential. To achieve this, tricolor (Red/Green/Blue(R/G/B))-selective OPD arrays for the receiver and tricolor OLED arrays for the emitter are developed. For (R/G/B)-selective OPDs, a Fabry-Pérot electrode to enhance color selectivity and a thick junction structure to effectively accommodate a wide range of driving voltages are introduced. For tricolor OLEDs, fluorescent-emitting materials are used to enhance the operating frequency in addition to introducing a cavity structure to achieve narrow emission. Utilizing these spectrally refined tricolor OPDs/OLEDs, a VLC system is designed for indoor lighting applications, and a systematic analysis of their signal-to-interference ratio dependence on the distance or angle between the transmitter and receiver is performed. The study's findings indicate the importance of emission angle-dependent wavelength shift of the OLED and the luminosity function, which varies with wavelength, in the R/G/B mixed-white-light-based VLC systems. Finally, the feasibility of VLC using tricolor OPDs/OLEDs in the real-life context of indoor white-color lighting is demonstrated, showing that the transmitted data patterns well-matched the received data patterns.

Pressure‐Induced Free Exciton Emission in a Quasi‐Zero‐Dimensional Hybrid Lead Halide

AbstractStructural dimensionality and electronic dimensionality play a crucial role in determining the type of excitonic emission in hybrid metal halides (HMHs). It is important but challenging to achieve free exciton (FE) emission in zero‐dimensional (0D) HMHs based on the control over the electronic dimensionality. In this work, a quasi‐0D HMH (C7H15N2Br)2PbBr4 with localized electronic dimensionality is prepared as a prototype model. With increasing pressure onto (C7H15N2Br)2PbBr4, the broad and weak self‐trapped exciton (STE) emission at ambient conditions is considerably enhanced before 3.6 GPa, which originates from more distorted [PbBr4]2− seesaw units upon compression. Notably, a narrow FE emission in (C7H15N2Br)2PbBr4 appears at 3.6 GPa, and then this FE emission is gradually strengthened up to 8.4 GPa. High pressure structural characterizations reveal that anisotropic contraction of (C7H15N2Br)2PbBr4 results in a noticeable reduction in the distance between adjacent [PbBr4]2− seesaw units, as well as an obvious enhancement of crystal stiffness. Consequently, the electronic connectivity in (C7H15N2Br)2PbBr4 is sufficiently promoted above 3.6 GPa, which is also supported with theoretical calculations. The elevation of electronic connectivity and enhanced stiffness together lead to pressure‐induced FE emission and subsequent emission enhancement in quasi‐0D (C7H15N2Br)2PbBr4.

Pressure-Induced Free Exciton Emission in a Quasi-Zero-Dimensional Hybrid Lead Halide.

Structural dimensionality and electronic dimensionality play a crucial role in determining the type of excitonic emission in hybrid metal halides (HMHs). It is important but challenging to achieve free exciton (FE) emission in zero-dimensional (0D) HMHs based on the control over the electronic dimensionality. In this work, a quasi-0D HMH (C7 H15 N2 Br)2 PbBr4 with localized electronic dimensionality is prepared as a prototype model. With increasing pressure onto (C7 H15 N2 Br)2 PbBr4 , the broad and weak self-trapped exciton (STE) emission at ambient conditions is considerably enhanced before 3.6 GPa, which originates from more distorted [PbBr4 ]2- seesaw units upon compression. Notably, a narrow FE emission in (C7 H15 N2 Br)2 PbBr4 appears at 3.6 GPa, and then this FE emission is gradually strengthened up to 8.4 GPa. High pressure structural characterizations reveal that anisotropic contraction of (C7 H15 N2 Br)2 PbBr4 results in a noticeable reduction in the distance between adjacent [PbBr4 ]2- seesaw units, as well as an obvious enhancement of crystal stiffness. Consequently, the electronic connectivity in (C7 H15 N2 Br)2 PbBr4 is sufficiently promoted above 3.6 GPa, which is also supported with theoretical calculations. The elevation of electronic connectivity and enhanced stiffness together lead to pressure-induced FE emission and subsequent emission enhancement in quasi-0D (C7 H15 N2 Br)2 PbBr4 .

A multifunctional emitter with synergistical adjustment of rigidity and flexibility for high-performance data-recording and organic light-emitting devices with “hot exciton” channel

An intramolecular dual-locking design is proposed for organic luminescent materials, aiming at synergistically adjusting the molecular rigidity and flexibility for applications in data storage and light-emitting devices. According to this concept, a multifunctional donor–acceptor type emitter, LPCz-TRZ, is developed, featuring a “soft” diphenylmethane lock and a “hard” single-bond lock in its donor moiety. The highly locked structure results in appreciable rigidity that endows LPCz-TRZ with high luminescence efficiency, narrow emission, promoted charge conductivity and triplet harvesting “hot exciton” channels, allowing high-performance deep-blue organic light-emitting diodes (OLEDs) with an external quantum efficiency as high as 7.88%, which is among the best deep-blue “hot exciton” OLEDs. Notably, the structure of LPCz-TRZ is semi-flexible, leading to unique mechanochromic luminescence (MCL) behavior. Compared to the conventional MCL emitters, the orchestration of rigidity and flexibility in LPCz-TRZ affords high-contrast, fatigue-resistance MCL, as evidenced by a simple, rewritable data-recording demonstration with negligible fatigue after up to 15 wiring-erasing cycles.

An Asymmetric Double-degenerate Type Ia Supernova Explosion with a Surviving Companion Star

We present nebular spectroscopy of SN 2020hvf, a Type Ia supernova (SN Ia) with an early bump in its light curve. SN 2020hvf shares many spectroscopic and photometric similarities to the carbon-rich high-luminosity “03fg-like” SNe Ia. At >240 days after peak brightness, we detect unambiguous emission from [Ca ii] λ λ7291, 7324, which is rarely observed in normal SNe Ia and only seen in peculiar subclasses. SN 2020hvf displays “sawtooth” emission profiles near 7300 Å that cannot be explained with single symmetric velocity components of [Fe ii], [Ni ii], and [Ca ii], indicating an asymmetric explosion. The broad [Ca ii] emission is best modeled by two velocity components offset by 1220 km s−1, which could be caused by ejecta associated with each star in the progenitor system, separated by their orbital velocity. For the first time in an SN Ia, we identify narrow (FWHM = 180 ± 40 km s−1) [Ca ii] emission, which we associate with a wind from a surviving, puffed-up companion star. Few published spectra have sufficient resolution and the signal-to-noise ratio necessary to detect similar narrow [Ca ii] emission; however, we have detected similar line profiles in other 03fg-like SNe Ia. The extremely narrow velocity width of [Ca ii] has only otherwise been observed in SNe Iax at late times. Since this event likely had a double-degenerate “super-Chandrasekhar” mass progenitor system, we suggest that a single white dwarf (WD) was fully disrupted and a wind from a surviving companion WD is producing the observed narrow emission. It is unclear whether this unique progenitor and explosion scenario can explain the diversity of 03fg-like SNe Ia, potentially indicating that multiple progenitor channels contribute to this subclass.

Distyrylbenzene-based semi-conducting molecular material for OLED applications: Synthesis, characterization and TD-DFT calculations

New semi-conducting molecular materiel (M-DSB) based on the distyrylbenzene π-conjugated system was synthesized via the Wittig reaction. The structural properties of M-DSB, displaying three different stereoisomers E-E, Z-Z and Z-E, were investigated through density functional theory (DFT) optimization. The detailed TD-DFT analysis provided insights into the structure-property relationships and revealed good agreement with experimental data. This photoactive material exhibits nearly the same UV–visible spectra in dilute solution and as solid thin film, with a maximum absorption at 363 nm and an optical gap of 2.99 eV. A broad and red-shifted photoluminescence spectrum was obtained in the solid state with blue emission compared to the solution which shows purplish blue emission with relatively narrow emission. The HOMO/LUMO energy levels were calculated by cyclic voltammetry measurements and indicate a p-type semiconductor material. The temperature and frequency dependence of the conductivity shows an activation energy value of about 0.89 eV for the M-DSB thin layer. Impedance spectroscopy of the ITO/M-DSB/Al device indicates a typical behavior of a single relaxation process and confirms that the electrical response becomes faster and the mobility of the charge carriers is enhanced by increasing the temperature.

Spectra of V1405 Cas at the Very Beginning Indicate a Low-mass ONeMg White Dwarf Progenitor

The lowest possible mass of ONeMg white dwarfs (WDs) has not been clarified despite its importance in the formation and evolution of WDs. We tackle this issue by studying the properties of V1405 Cas (Nova Cassiopeiae 2021), which is an outlier given a combination of its very slow light-curve evolution and the recently reported neon-nova identification. We report its rapid spectral evolution in the initial phase, covering 9.88, 23.77, 33.94, 53.53, 71.79, and 81.90 hr after the discovery. The first spectrum is characterized by lines from highly ionized species, most noticeably He ii and N iii. These lines are quickly replaced by lower-ionization lines, e.g., N ii, Si ii, and O i. In addition, Al ii (6237 Å) starts emerging as an emission line at the second epoch. We perform emission-line strength diagnostics, showing that the density and temperature quickly decrease toward later epochs. This behavior, together with the decreasing velocity seen in Hα, Hβ, and He i, indicates that the initial nova dynamics is reasonably well described by an expanding fireball on top of an expanding photosphere. Interestingly, the strengths of the N iii and Al ii indicate large enhancement in abundance, pointing to a ONeMg WD progenitor as is consistent with its neon-nova classification. Given its low-mass nature inferred by the slow light-curve evolution and relatively narrow emission lines, it provides a challenge to the stellar evolution theory that predicts the lower limit of the ONeMg WD mass being ∼1.1 M ⊙.

Optical properties of Tb3+- and Cr3+-doped MgAl2O4 ceramics prepared by capsule- and carbon-free hot isostatic pressing

Transparent spinel with high real in-line transmittance (RIT up to 79%) was prepared from commercial spinel powder by capsule-free hot isostatic pressing (HIP). Optimal pre-sintering conditions were found in order to enhance the RIT values and doping with Cr3+ (0.01–0.04 at%) and Tb3+ (0.05–0.125 at%) secured photoluminescence. The incorporation of the dopants in tested range does not noticeably reduced the RIT. The Cr3+-doped MgAl2O4 shows efficient narrow red emission at about 685 nm (R-line) due to the 2Eg→4A2g transition of Cr3+ ions located in octahedral sites of D3d local symmetry with a strong crystal field. The Tb3+-doped MgAl2O4 ceramics have shown emissions from blue to red spectral range (5D4→7F3–6 transitions), with prominent green emission centered at 545 nm. The maximal emission intensity was achieved at 0.075 at% of Tb3+, Further increase of Tb3+ content led to the concentration quenching caused by Tb3+ ions segregation at the grain boundaries.

Nd3+ doped oxide thermal probes based on luminescence intensity ratio within BW-II and excitation in BW-I

The Nd3+ have taken a central place in the field of nanothermometry thanks to the presence of several narrow Stark emission and is easily excited through the lasers commercially available. With the goal to boost the development of Nd3+-based nanothermometers, especially working with emissions into BW-II, the thermal response of different oxide matrices Y2O3, Y2Ge2O7, Y3Al5O12, YBO3, and Y3BO6 were evaluated considering emissions from the Nd3+ 4F3/2 → 4I11/2 transition, which falls into the BW-II. Interestingly, we observed these lines are more intense than those located in BW-I, which can enhance the signal-to-noise ratio. Therefore, the design of thermal probes emitting in BW-II showed to be an excellent strategy to provide more accurate thermal sensing as the scattering of the light by the tissues is reduced in BW-II. In light of this, we also maximized the luminescence intensity of the matrices by Nd3+ doping from 0.1 to 10 mol%. Furthermore, their structure and luminescence properties were investigated using X-ray diffraction, transmission electron microscope, diffuse reflectance spectroscopy, photoluminescence, and radiative decay curve measurements. Additionally, exploring thermal response and luminescence emission optimization in several compounds offers enriched information support to design new high-level Nd3+-based thermal probes. Among Y2O3, Y2Ge2O7, Y3Al5O12 (YAG), YBO3, and Y3BO6 matrices studied, Y2O3 is the promising matrix to conduct thermal sensing due to exhibiting the highest Sr value around 0.4 %.K−1 in which 0.5 mol% Nd3+ is the deal doping to maximize its luminescence intensity.

High-performance amplified spontaneous emission in inorganic CsPbBr3 perovskite thin films grown on engineered quartz substrates.

In this work, periodic rectangular arrays were fabricated on quartz substrates using the femtosecond laser ablation technique, on which inorganic cesium lead bromide thin films were grown using the spin coating method. Enhanced photoluminescence emission was investigated using a homebuilt confocal microscope, and increased light absorption due to the engineered structures was also measured. High-performance amplified spontaneous emission with typical narrow lasing emission peaks excited using a nanosecond laser centered at 266 nm was obtained. This work provides a method to modify the performance of optoelectrical devices, which helps develop light-emitting diodes, photodetectors, solar cells, and lasers.

Solid superacid catalysts promote high-performance carbon dots with narrow-band fluorescence emission for luminescence solar concentrators

Facile and efficient method for constructing carbon dots (CDs) with narrow full width at half maximum (FWHM) is a major challenge in the field, and researches on regulating the FWHM of CDs are also rare and scarce. In this work, we delved into the synthesis of CDs with narrow fluorescence emission FWHM (NFEF-CDs) in the m-phenylenediamine (m-PD)/ethanol system, utilizing solid superacid resin as catalyst with solvothermal method. The resulting NFEF-CDs exhibit a photoluminescent (PL) emission peak at 521 nm with a narrow FWHM of 41 nm, an absolute PL quantum yield (QY) of 80%, and display excitation-independent PL behavior. Through comprehensive characterization, we identified the protonation of edge amino on NFEF-CDs as the key factor in achieving the narrow FWHM. Subsequently, we validated the broad applicability of solid superacid resins as catalysts for synthesizing CDs with narrow FWHM in the m-PD/ethanol system. Finally, we utilized a self-leveling method to prepare NFEF-CDs film on the surface of poly(methyl methacrylate) (PMMA) substrate and investigated the solid-state fluorescence properties of NFEF-CDs as well as their performance as luminescence solar concentrator (LSC) for photovoltaic conversion. The results revealed that the as-prepared LSC exhibit an internal quantum efficiency (ηint) of 42.39% and an optical efficiency (ηopt) of 0.68%. These findings demonstrate the promising prospects of NFEF-CDs in the field of LSCs and provide a theoretical basis for their application in photovoltaic conversion.

Ejecta, Rings, and Dust in SN 1987A with JWST MIRI/MRS

Supernova (SN) 1987A is the nearest supernova in ∼400 yr. Using the JWST MIRI Medium Resolution Spectrograph, we spatially resolved the ejecta, equatorial ring (ER), and outer rings in the mid-infrared 12,927 days (35.4 yr) after the explosion. The spectra are rich in line and dust continuum emission, both in the ejecta and the ring. The broad emission lines (280–380 km s−1 FWHM) that are seen from all singly-ionized species originate from the expanding ER, with properties consistent with dense post-shock cooling gas. Narrower emission lines (100–170 km s−1 FWHM) are seen from species originating from a more extended lower-density component whose high ionization may have been produced by shocks progressing through the ER or by the UV radiation pulse associated with the original supernova event. The asymmetric east–west dust emission in the ER has continued to fade, with constant temperature, signifying a reduction in dust mass. Small grains in the ER are preferentially destroyed, with larger grains from the progenitor surviving the transition from SN into SNR. The ER dust is fit with a single set of optical constants, eliminating the need for a secondary featureless hot dust component. We find several broad ejecta emission lines from [Ne ii], [Ar ii], [Fe ii], and [Ni ii]. With the exception of [Fe ii] 25.99 μm, these all originate from the ejecta close to the ring and are likely to be excited by X-rays from the interaction. The [Fe ii] 5.34 to 25.99 μm line ratio indicates a temperature of only a few hundred K in the inner core, which is consistent with being powered by 44 Ti decay.