Narrow-band Emission Research Articles

High-sensitivity multi-gas detection using dual-ridge metasurface emitters with polarization-distinguishable emission spectra

The metasurface thermal emitter offers an energy-efficient, compact, and sensitive solution as a radiation source for non-contact gas detection, enabling the “molecular fingerprint” technique to be widely applied, from medical diagnostics to environmental monitoring. However, most narrowband emitters are designed for a single target gas, hindering the miniaturization of multi-gas detection systems. In this work, a one-dimensional dual-ridge grating emitter is employed, achieving dual-band and tri-band polarization-distinguishable emission spectra through the excitation of Fabry-Perot (FP) resonances and quasi-bound states in the continuum (qBICs). These emission spectra can be readily matched to multiple non-overlapping absorption peaks of gases such as CH4, CO2, CO, NO, and NH3 within the 3–6 µm range, thereby reducing the impact of mixed gases on measurements. Compared to conventional metal-dielectric-metal structures, the use of a single metal layer results in lower material losses, enabling higher Q-factors and more pronounced directional radiation intensity variations. Furthermore, adjusting the asymmetry to modulate the qBIC-excited absorption peaks does not affect the Q-factor of the FP resonance absorption, thus achieving high-sensitivity multi-band gas detection. This work provides a promising approach for the miniaturization and integration of multi-gas channel detection, facilitating more accurate and sensitive sensing strategies.

Spectrally narrowband simultaneous dual-wavelength emission from Y-branch DBR diode lasers at 785 nm

Y-branch distributed Bragg reflector (DBR) diode lasers with a stable narrowband emission in simultaneous dual-wavelength operation with spectral distances below 3.2 nm are presented. The Y-branch laser consists of two laser branches with different DBR gratings serving as wavelength-selective rear-side mirrors. Therefore, two emission wavelengths with a spectral distance defined by the DBR grating periods can be generated simultaneously. A Y-coupler combines the two ridge waveguide (RW) branches into a single straight output RW. Devices with a spectral distance of 0.6 nm and 2.0 nm emitting around 785 nm are manufactured. Selecting the operation parameters carefully, stable narrowband emission for both wavelengths is obtained. Resistors serving as heaters implemented next to the DBR gratings allow for wavelength adjustment and a tuning of the spectral distance. At an optical output power of 100 mW, the spectral distance can be shifted from 0 to 1.55 nm (0–0.76 THz) for the former device or from 1.00 to 3.15 nm (0.49–1.54 THz) for the latter device, respectively. This makes the Y-branch DBR diode laser particularly interesting for the generation of THz beat-note signals, needed to generate THz radiation via photo-mixing.

Narrowband Electroluminescence from Color Centers in Hexagonal Boron Nitride.

Defects in wide bandgap materials have emerged as promising candidates for solid-state quantum optical technologies. Electrical excitation of single emitters may lead to scalable on-chip devices and therefore is highly sought after. However, most wide bandgap materials are not amenable to efficient doping, posing challenges for electrical excitation and on-chip integration. Here, we demonstrate narrowband electroluminescence from visible and near-infrared color centers in hexagonal boron nitride (hBN). We harness van der Waals tunnel junctions of graphene-hBN-graphene. Charge carriers are electrically injected into hBN, exciting localized defects that emit nonclassical light, as characterized by the second order correlation measurement. Remarkably, the devices operate at room temperature and produce robust, narrowband emission spanning from visible to the near-infrared. Our work marks an important milestone in vdW materials and their promising attributes for integrated quantum technologies and on-chip photonic circuits.

Intrinsic Narrowband Blue Phosphorescent Materials and Their Applications in 3D Printed Self-monitoring Microfluidic Chips.

Organic room-temperature phosphorescent (RTP) materials, especially with narrowband emission properties, exhibit great potential for applications in display and sensing, but have been seldom reported. Herein, a rare example of the intrinsic narrowband blue RTP material is fabricated and reported. A series of indolo[3,2,1-kl]phenothiazine derivatives, named Cphpz, 1O-Cphpz, and 2O-Cphpz, are designed and synthesized. Due to their relatively rigid structures, these three compounds showed deep blue narrowband emissions ranging from 396 to 434nm with the full width at half maximum (FWHM) of 31, 26, and 31nm, respectively. To the delight, compound 2O-Cphpz displayed intrinsic narrowband blue RTP at 448 nm with FWHM of 36 nm and a long-lived lifetime of 1.08 s in hydroxyethyl acrylate and acrylic acid matrix. Photophysical studies, single crystal analyses, and TD-DFT calculations are performed to elucidate further the relationships between molecular structures and the narrowband blue RTP properties. Meanwhile, because the narrowband blue RTP is highly sensitive to humidity, a visualizing droplet path optical microfluidic chip is efficiently fabricated through the digital light processing 3D printing.This work provides a rare example and a reliable strategy to realize narrowband blue RTP and further expand their applications in self-monitoring 3D printed structures.

Boron‐Dipyrromethene Emitters with Strengthened Rigidity and Restricted Scissoring Vibration for High‐Performance OLEDs With Deep‐Red Narrowband Emission

Boron‐Dipyrromethene Emitters with Strengthened Rigidity and Restricted Scissoring Vibration for High‐Performance OLEDs With Deep‐Red Narrowband Emission

Mn2+ doped aluminum-rich spinel transparent ceramic phosphor with higher performance for wide color-gamut backlight display

Due to the great potential of narrow-band green-emitting phosphors for wide color-gamut white light-emitting diodes (WLED) backlight displays, there is great interest in finding host materials with the desired luminescent properties and high quantum efficiency. Herein, a series of Mg0.98-xAl2(1+x/3)O4: 0.02Mn2+ (x = 0, 0.125, 0.25) powders were synthesized using high-temperature solid-phase reactions, followed by a combination of pressureless sintering and hot isostatic pressure sintering to fabricate transparent ceramic phosphors. The crystal structure refinement, NMR spectroscopy, and photoluminescence results show tetrahedral coordination of Mn2+ ions and an increase in cation vacancies and disorder with increasing x. These transparent ceramics exhibit narrow-band green emission, which shifts from 523 to 520 nm with increasing x. The Mg0.855Al2.08O4: 0.02Mn2+ ceramic sample has an in-line transmittance of over 80 % above 500 nm and internal quantum efficiencies as high as 96.2 %. The luminous intensity of the Mg0.855Al2.08O4: 0.02Mn2+ ceramic remains above 88.6 % at 425 K compared to room temperature, with a thermal conductivity of 12.4 W·m−1·K−1. A WLED device fabricated using the Mg0.855Al2.08O4: 0.02Mn2+ ceramic, K2SiF6:Mn4+ phosphors, and a blue chip show a wide color gamut of 126 % National Television System Committee standard. The results show that Mn2+-doped aluminum-rich spinel transparent ceramics have great potential for application in wide color gamut WLED backlight devices.

Precise Regulation of the Reverse Intersystem Crossing Pathway by Hybridized Long-Short Axis Strategy for High-Performance Multi-Resonance TADF Emitters.

Multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules have experienced great success in organic light-emitting diodes (OLEDs) owing to their outstanding quantum efficiencies and narrow full width at half-maximums (FWHMs). However, the reverse intersystem crossing (RISC) rates of MR-TADF emitters are usually small, which will lead to relatively long triplet exciton lifetime and severe efficiency roll-off. Here, we report an effective molecular design strategy to introduce multichannel RISC pathways and thus increase RISC rates without compromising the color fidelity and emission efficiency by the "hybridized long-short axis (HLSA)" strategy. The TPA-CN-BN shows a near-unity photoluminescence quantum yield, rapid RISC rate of 1.4 × 105 s-1, narrow FWHM of 23 nm, and small singlet-triplet energy gap (ΔEST) of 0.06 eV in solution. The non-sensitized OLED based on TPA-CN-BN exhibits a narrowband emission with the FWHM of 31 nm, in company with external quantum efficiency (EQE) of 37.9%. Notably, the device exhibits the low efficiency roll-off as the EQEs maintain 34.8% and 21.8% at 100 and 1000 cd m-2, respectively, representing the best performance for single-host OLEDs based on the BCzBN skeleton. This study provides a fresh and promising approach to realize high-performance OLEDs with high color purity and remarkable device efficiency.

High color purity aluminate phosphor SryCa1-x-yAl12O19: xEu2+ for lighting and backlight display applications

In the context of the rapid advances in electronic information technology, the advancement of novel high-efficiency narrow-band blue phosphors represents a pivotal step in the advancement of high-quality liquid crystal displays (LCDs), as well as the development of white light-emitting diodes (WLEDs) with a reduced correlated color temperature (CCT). In this study, based on the sensitivity of Eu2+ emission to local environment, the alkaline earth aluminate material CaAl12O19 with high structural symmetry was selected as the matrix, and the symmetry of crystal structure was improved by replacing Ca2+ with Sr2+, the narrow-band emission of the phosphor is realized. The Sr0.9Ca0.09Al12O19: 0.01Eu2+ (SCAO: Eu2+) phosphor exhibited narrow-band emission with the full width at half maximum (FWHM) of 45.76 nm, and the colour purity of up to 95.46 %. Moreover, the internal quantum efficiency (IQE) of SCAO: Eu2+ has been demonstrated to reach 81.70 %. In addition, SCAO: Eu2+ phosphor, (Ba, Sr)2SiO4: Eu2+ phosphor, CaAlSiN3: Eu2+ phosphor, and 275 nm UVLED chips were combined to prepare white LED devices exhibiting a low color temperature (3733 K). The three-band LEDs of SCAO: Eu2+, β-Sialon: Eu2+ and K2SiF6: Mn4+ exhibited a colour gamut covering 84.75 % of the National Television Standards Committee (NTSC) standard. This indicates that the phosphor possesses the characteristics of a highly effective narrow-band blue-light-emitting substance with considerable potential for utilization in lighting and backlighting displays.

Precise Regulation of the Reverse Intersystem Crossing Pathway by Hybridized Long‐Short Axis Strategy for High‐Performance Multi‐Resonance TADF Emitters

Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) molecules have experienced great success in organic light‐emitting diodes (OLEDs) owing to their outstanding quantum efficiencies and narrow full width at half‐maximums (FWHMs). However, the reverse intersystem crossing (RISC) rates of MR‐TADF emitters are usually small, which will lead to relatively long triplet exciton lifetime and severe efficiency roll‐off. Here, we report an effective molecular design strategy to introduce multichannel RISC pathways and thus increase RISC rates without compromising the color fidelity and emission efficiency by the “hybridized long‐short axis (HLSA)” strategy. The TPA‐CN‐BN shows a near‐unity photoluminescence quantum yield, rapid RISC rate of 1.4 × 105 s‐1, narrow FWHM of 23 nm, and small singlet‐triplet energy gap (ΔEST) of 0.06 eV in solution. The non‐sensitized OLED based on TPA‐CN‐BN exhibits a narrowband emission with the FWHM of 31 nm, in company with external quantum efficiency (EQE) of 37.9%. Notably, the device exhibits the low efficiency roll‐off as the EQEs maintain 34.8% and 21.8% at 100 and 1000 cd m‐2, respectively, representing the best performance for single‐host OLEDs based on the BCzBN skeleton. This study provides a fresh and promising approach to realize high‐performance OLEDs with high color purity and remarkable device efficiency.

π‐Extended Phenoxazine‐Based Asymmetric MR‐TADF Emitters for Narrow Emission Band Green OLEDs with a Power Efficiency of 150 lm W−1, an EQE of 27%, and an LT95 of Over 3000 h at 1000 cdm−2

AbstractAlthough multi‐resonance thermally activated delayed fluorescent (MR‐TADF) emitters simultaneously achieve high color purity and high efficiency in organic light‐emitting devices (OLEDs), MR‐TADF‐based OLEDs suffer from severe efficiency roll‐off and lifetime issues for practical application. To overcome these issues, a key solution is hyper OLED technology sensitized by TADF or phosphorescent emitters. In this study, a series of π‐extended phenoxazine‐based asymmetric MR‐TADF emitters for long lifetime, low‐power consumption, and narrow emission band green OLEDs is developed. As a sensitizer, a well‐known phosphorescent emitter is used, fac‐tris(2‐phenylpyridinato‐C2,N)iridium(III) [Ir(ppy)3]. Consequently, these MR‐TADF emitters achieve hyper OLEDs with a power efficiency of 150 lm W−1, an external quantum efficiency of 27%, and a long lifetime LT95 of over 3000 h at high brightness of 1000 cdm−2. These performances are among the best in scientific literature.

Near-Infrared Emitting Helically Twisted Conjugated Frameworks Consisting of Alternant Donor-π-Acceptor Units and Multiple Boron Atoms.

A novel design strategy to construct bright and narrow near-infrared (NIR) emission materials with suppressed shoulder peaks can significantly enhance their performance in various applications. Herein, we have successfully synthesized a series of helically twisted D-π-A conjugated systems bridged by boron atoms, achieving bright red to near-infrared (NIR) emissions with notably narrow full-width at half-maximum (FWHM) values of 35 nm (0.08 eV) and photoluminescence quantum yield (PLQY) up to 80%. These compounds display redshifted emissions up to 753 nm in higher concentrations. Cis/trans configurational isomers of multi-boron-bridged molecule BN3 exhibit similar photophysical properties. The unique combination of boron-induced coordination-enhanced charge transfer (CE-CT) and the helically twisted conjugated framework is pivotal in achieving the redshifted, narrowband emission. X-ray crystallographic analysis of BN2 and BN3-a reveals that the extension of boron-bridged D-π-A skeletons significantly increases the distortion of the skeleton. Systematic theoretical calculations show how the boron CE-CT mechanism, in conjunction with the helical twist, leads to the narrowing of emission bands while simultaneously red-shifting them into the NIR region. This work could open new avenues for the development of advanced materials with tailored optical properties, particularly in the challenging and highly sought-after NIR spectrum.

B-211 Quantum dot-DNA nanocomposite enhanced single-molecule flow (SiM-Flow) for ultrasensitive microRNA detection in metastatic castrate-resistant prostate cancer

Abstract Background MicroRNAs (miRs) like miR-375 and miR-1290 are associated with cancer progression and chemoresistance in metastatic castrate-resistant prostate cancer (mCRPC). However, these prognostic biomarkers are typically present in low abundance (0.1∼1 fM) in patient plasma, which is close to the detection limit of the current gold standard techniques, quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Therefore, we tested a nanomaterial that incorporates quantum dots (QDs) and DNA amplicons for enhanced in-solution counting applications in plasma from a cohort of mCRPC patients. The QD-DNA nanocomposite increases the fluorescent intensity of an individual amplicon for ultrasensitive flow-counting and provides higher multiplex capacity due to the narrow emission band of QD for simple instrumentation. Methods QDs were synthesized with spectrally distinct emission bands by tuning the size or composition of CdSe core. QDs were then coated with multidentate polymer allowing further bioconjugations and better solubility in aqueous solution. The oligonucleotides complementary to amplicons generated from selected miR targets (prognostic biomarkers: miR-1290 and miR-375; normalization biomarkers: miR-16, miR-30a-5p, and cel-39) were then conjugated to QDs with optimized ratio. Total RNA was extracted from a screening cohort of 14 mCRPC patients from Huntsman Cancer Institute where platelet-poor plasma was uniformly processed with exogenous spike-in, cel-39, added in. qRT-PCR was performed using TaqMan miRNA assays, and SiM-Flow was conducted using a commercial flow cytometry to count QD barcoded enzymatic-extended miRs nanoparticles. The DNA template used for extending miRs was designed by our lab and purchased from IDT-DNA. Pearson correlation and interclass agreement analysis were applied to evaluate the concordance between the two assays. The mCRPC cohort was followed for clinical outcomes, and survival analysis for the time of progression from mCRPC to death/last follow-up was performed to determine the prognostic value of the QD-DNA nanoparticle counts. The Cox proportional hazards model was applied to linearly incorporate multiple hazard factors of patients for multivariate survival analysis. Results We demonstrated the multiplex ability of QDs with less than 5% false positive rate. The machine learning-guided optimized assay shows a 1000-time improved limit of detection of assay compared to the published literature. Interclass agreement > 0.9 and Pearson correlation of 0.94 between SiM-Flow and RT-qPCR on human plasma extracts suggest high specificity of SiM-Flow on miR detection. Also, miR-375 was identified among all the samples through SiM-Flow, although it was unidentified by qRT-PCR in 14 samples. Higher levels of miR-1290, miR-375, and prostate-specific antigen were significantly associated with poor overall survival (p=0.019) in the initial survival analysis. Survival analysis replication is ongoing in an independent mCRPC cohort. Conclusions SiM-Flow was able to detect target miRs in mCRPC patients’ plasma with a high agreement with qRT-PCR and lower detection limit and demonstrated multiplex ability with a simple optical set-up. This shows technological advancement in the detection of cancer-associated biomarkers and will aid in precision medicine therapeutic and point-of-care applications with both prognostic and predictive potential.

Functionalized europium infused-polystyrene nanoparticles for bacteria labeling for microscopic imaging

Luminescence microscopic imaging has become an indispensable tool in diagnostics and therapeutics. Lanthanide luminescent complexes (LLCs) have proven to be invaluable in this endeavor due to certain attractive characteristics such as long decay times, large Richardson shifts and narrow emission bands. However, the insolubility of these complexes and the negative effects of the aqueous environment on their photophysical properties still restrict their biological applications. By embedding luminescent Eu3+ complexes into polystyrene nanoparticles (NPs), these complexes can not only maintain their photophysical properties, but even enhance them. This leads to exceptionally high quantum yields (> 90%) and decay times ( >800 μs). In addition, the surfaces of the NPs described here are covered with primary amine groups, which may be exploited for various interesting bioconjugation chemistries. In the present application, they were modified with N-hydroxysuccinimide (NHS) esters and then coupled either electrostatically or covalently to both, gram positive and negative bacteria, labeling them for luminescence microscopic imaging. This, to the best of our knowledge, is the first report of polymer NPs infused with LLCs for bacteria labeling.

Elevating Red Emission: Yb3+ Doped CsPbBr1I2 Nanocrystal Glass for Exceptional PLQY and Stability in Wide Color Gamut Backlit Displays

As display technologies progress towards enhanced visual performance, there was a growing demand for color conversion materials to meet increasingly stringent performance requirements. In recent years, all-inorganic perovskite CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) had gained attention in the field of wide color gamut backlight displays due to their tunable full spectrum, narrow-band emission, high color purity, and ease of processing. However, red-emitting perovskite NCs were still facing challenges with photoluminescence quantum yield (PLQY) and stability. In this study, Yb3+ doped CsPbBr1I2 perovskite nanocrystal glass (Yb3+@CsPbBr1I2 PNG) was synthesized using a melt-quenching technique. Samples emitting at a narrow band centered at 630nm, with a full width at half maximum(FWHM) of 31.8nm, exhibited a high PLQY of 80.36% and retained fluorescence intensity at 98.2% of the initial value in water, maintaining to 92.6% after continuous blue light irradiation for 60 days. Moreover, the optical conversion film Yb3+@CsPbBr1I2@CsPbBr3@PET developed in our study showcased color gamut coverage surpassing 132.9% of the NTSC 1953 standard and 98.8% of the Rec.2020 standard. In summary, the highly efficient and remarkably stable red-emitting Yb3+@CsPbBr1I2 PNG composite material introduced in this study paved the way for future advancements in wide color gamut and ultra-high definition backlight display technologies.

Efficient manipulation of photoluminescence by organic cations and Sb doping in hybrid manganese chlorides

Zero-dimensional (0D) Mn(II)-based hybrids with the typical d–d transitions have been rapidly developed benefitting from the environmental friendliness, blue light excitation and the high thermal stability. Herein, we first designed two novel green-emitting 0D Mn(II)-based hybrids (C16H28N)2MnCl4 and (C21H46N)2MnCl4, where the organic cations cocrystallize with four-coordinated [MnCl4]2- tetrahedrons. Upon blue-light excitation, these two crystals exhibited narrow-band green emission with distinct emission intensity and FWHM as well as thermal quenching behavior, which is analyzed by the influence of the crystal structure of different organic cations on the luminescence performance. Furthermore, multiple emission color can be observed from green to orange-red in (C16H28N)2MnCl4:Sb3+ by regulating the [SbCl5]2-/[MnCl4]2- molar ratio or excitation wavelength. Our study not only enriches the influence of organic cations on crystal structure and luminescence performance, but also provides a new direction towards realizing the multi-color emission by Sb3+ ions doping strategy.

Exciton Dissociation and Recombination Afford Narrowband Organic Afterglow Through Efficient FRET.

Organic afterglow with long-persistent luminescence (LPL) after photoexcitation is highly attractive, but the realization of narrowband afterglow with small full-width at half-maximum (FWHM) is a huge challenge since it is intrinsically contradictory to the triplet- and solid-state emission nature of organic afterglow. Here, narrow-band, long-lived, and full-color organic LPL is realized by isolating multi-resonant thermally activated delayed fluorescent (MR-TADF) fluorophores in a glassy steroid-type host through a facile melt-cooling treatment. Such prepared host becomes capable of exciton dissociation and recombination (EDR) upon photoirradiation for both long-lived fluorescence and phosphorescence; and, the efficient Förster resonance energy transfer (FRET) from the host to various MR-TADF emitters leads to high-performance LPL, exhibiting small FWHM of 33nm, long persistent time over 10s, and facile color-tuning in a wide range from deep-blue to orange (414-600nm). Moreover, with the extraordinary narrowband LPL and easy processability of the material, centimeter-scale flexible optical waveguide fibers and integrated FWHM/color/lifetime-resolved multilevel encryption/decryption devices have been designed and fabricated. This novel EDR and singlet/triplet-to-singlet FRET strategy to achieve excellent LPL performances illustrates a promising way for constructing flexible organic afterglow with easy preparation methods, shedding valuable scientific insights into the design of narrow-band emission in organic afterglow.

In-situ preparation of lanthanide luminescent MOF hydrogel for aldehyde detection☆

Metal-organic frameworks (MOFs) usually exist in the state of powder or crystal. When they are exposed to hydrophilic solvents, their structure will change and become unstable. Therefore, it is a challenge to construct MOF materials with tunable mechanical properties. Herein, we report in-situ growth lanthanide metal-organic framework (LnMOF) in sodium alginate (SA) and polyvinyl alcohol (PVA) hydrogel matrix. The prepared composite hydrogel not only displays characteristic lanthanide narrow-band emission under ultraviolet light, but also demonstrates excellent mechanical properties. The addition of LnMOF significantly enhances the compressive strength of the hydrogel (from 0.75 to 7.32 MPa). Furthermore, the composite hydrogel shows highly selective recognition of glutaraldehyde and gaseous formaldehyde at room temperature. The detection limits (LOD) of SP-EuMOF for glutaraldehyde and formaldehyde are 0.27 and 0.22 ppm, respectively. Based on these results, the LnMOF composite hydrogel is deemed to have significant potential as a fluorescent sensor for both glutaraldehyde and formaldehyde detection.

Insights into the Structural Modification of Selenium-Doped Derivatives with Narrowband Emissions: A Theory Study.

The research on boron/nitrogen (B/N)-based multiresonance thermally activated delayed fluorescence (MR-TADF) emitters has been a prominent topic due to their narrowband emission and high luminous efficiency. However, devices derived from the common types of narrowband TADF materials often experience an efficiency roll-off, which could be ascribed to their relatively slow triplet-singlet exciton interconversion. Since inserting the heavy Se atom into the B/N scheme has been a proven strategy to address the abovementioned issues, herein, extensive density functional theory (DFT) and time-dependent DFT (TD-DFT) simulations have been employed to explore the effects of the structural modification on a series of structurally modified selenium-doped derivatives. Furthermore, the two-layered ONIOM (QM/MM) model has been employed to study the pressure effects on the crystal structure and photophysical properties of the pristine CzBSe. The theoretical results found that the introduced tert-butyl units in Cz-BSeN could result in a shorter charge transfer distance and smaller reorganization energy than the parent CzBSe. In contrast to directly incorporating the o-carborane (Cb) unit to CzBSe, incorporating the bridged phenyl units is important in order to achieve narrowband emissions and high luminous efficiency. The lowest three triplet excited states of CzBSe, Cz-BSeN and PhCb-BSeN all contribute to their triplet-singlet exciton conversions, resulting in a high utilization of triplet excitons. The pressure has an evident influence on the photophysical properties of the aggregated CzBSe and is favored for obtaining narrowband emissions. Our work is promised to provide a feasible strategy for designing selenium-doped derivatives with narrowband emissions and rapid triplet-singlet exciton interconversions.

Luminescent lanthanide metallopeptides for biomolecule sensing and cellular imaging.

Lanthanide ions display unique luminescent properties that make them particularly attractive for the development of bioprobes, including long-lived excited states that allow the implementation of time-gated experiments and the elimination of background fluorescence associated with biological media, as well as narrow emission bands in comparison with typical organic fluorophores, which allow ratiometric and multiplex assays. These luminescent complexes can be combined with peptide ligands to endow them with additional targeting, responsiveness, and selectivity, thus multiplying the opportunities for creative probe design. In this feature article we will present some of the main strategies that researchers have used to develop lanthanide metallopeptide probes for the detection of proteins and nucleic acids, as well as for monitoring enzymatic activity and cellular imaging.

Advances and Challenges in Large-Area Perovskite Light-Emitting Diodes.

Metal halide perovskite light-emitting diodes (PeLEDs) have shown promise for high-definition displays and flat-panel lighting because of their wide color gamut, narrow emission band, and high brightness. The external quantum efficiency of PeLEDs increased rapidly from ≈1% to more than 25% in the past few years. However, most of these high-performance devices are fabricated using a spin coating method with a small device area of <0.1 cm2, limiting their commercial applications. Recently, large-area PeLEDs have attracted growing attention and significant breakthroughs have been reported. This perspective first introduces the pros and cons of each technique in making large-area PeLEDs. The advances in the fabrication of large-area PeLEDs are then summarized using spin coating and mass-production methods such as inkjet printing, blade coating, and thermal evaporation. Moreover, the challenging issues will be discussed that are urgent to be solved for large-area PeLEDs.