Luminescence Enhancement Research Articles

Bio-inspired optical structures for enhancing luminescence.

Luminescence is an essential signal for many plants, insects, and marine organisms to attract the opposite sex, avoid predators, and so on. Most luminescent living organisms have ingenious optical structures which can help them get high luminescent performances. These remarkable and efficient structures have been formed by natural selection from long-time evolution. Researchers keenly observed the enhanced luminescence phenomena and studied how these phenomena happen in order to learn the characteristics of bio-photonics. In this review, we summarize the optical structures for enhancing luminescence and their applications. The structures are classified according to their different functions. We focus on how researchers use these biological inspirations to enhance different luminescence processes, such as chemiluminescence (CL), photoluminescence (PL), and electroluminescence (EL). It lays a foundation for further research on the applications of luminescence enhancement. Furthermore, we give examples of luminescence enhancement by bio-inspired structures in information encryption, biochemical detection, and light sources. These examples show that it is possible to use bio-inspired optical structures to solve complex problems in optical applications. Our work will provide guidance for research on biomimetic optics, micro- and nano-optical structures, and enhanced luminescence.

Distinct Luminescent Thermal Behaviors of Yb3+- and Nd3+-Sensitized Core/Shell Upconversion Nanocrystals

Luminescent materials generally exhibit the thermal quenching due to accelerated nonradiative transitions at elevated temperatures. Recently, the discovery of anomalous thermally induced luminescence enhancement in lanthanide-doped upconversion nanocrystals (UCNCs) has aroused wide attention. The research on this topic not only deepens the understanding on the upconversion luminescence (UCL) mechanism but also promotes frontier applications based on UCNCs. Herein, comparative studies on temperature-dependent UCL properties were performed between Yb3+- and Nd3+-sensitized active-core/active-shell UCNCs. Opposite luminescent thermal behaviors were revealed for these two types of core/shell NCs, and the underlying mechanisms were elucidated with the assistance of temperature-dependent steady/transient spectral analysis under various atmospheres. Yb3+-sensitized active-core/active-shell NCs exhibited an anomalous luminescence enhancement with increasing temperature, which was attributed to the thermally alleviated quenching of surface-adsorbed water molecules. By contrast, Nd3+-sensitized active-core/active-shell NCs showed a normal thermal quenching due to rapidly increased deactivation rates of Nd3+ ions at elevated temperatures, although their UCL intensity was also affected by the quenching effect of surface-adsorbed water molecules. Highly secure anti-counterfeiting patterns were also demonstrated using the nanohybrids of Yb3+- and Nd3+-sensitized core/shell UCNCs as luminescent inks on the basis of their opposite luminescent thermal behaviors. This work provides new insights into luminescent thermal behaviors and energy loss pathways of lanthanide-doped UCNCs.

Simultaneous enhancement upconversion luminescence and photocatalytic properties of BiOBr:Yb3+, Er3+ nanosheets by optically inert ions doping

Lanthanide-doped upconversion (UC) materials are important in near-infrared (NIR) photocatalytic field because they can harvest NIR photons and then emit high-energy UV and visible light via the UC process. However, these materials still exhibit low UC luminescence efficiency, which strongly limits their practical applications. Herein, we report UC luminescence enhancement in BiOBr: Yb3+, Er3+ (BYE) nanosheets by doping Li+ and Zn2+ and the elucidation of the enhancement mechanism. The XRD and Rietveld refinement results showed that the doping improved the crystallinity of the samples, with the effect of codoping being more pronounced than that of single doping. Under 980-nm laser excitation, the red emission of the Li+-Zn2+-codoped BYE sample increased drastically by 2.5, 4.3, and 5.3 times than that of the Li+-doped BYE, Zn2+-doped BYE, and BYE samples, respectively. The luminescence enhancement could be ascribed to the reduction of the crystal site symmetry and the improvement of the crystallinity upon Li+ and Zn2+ doping. Moreover, photocatalytic experiments showed that Li+ and Zn2+ doped BYE exhibited better photocatalytic performance than BYE, thus paving the way toward achieving enhanced UC luminescence efficiency.

Improved broadband near-infrared luminescence in Nd3+/Tm3+ co-doping tellurite glass with Ag NPs

The near-infrared (NIR) luminescence in S+E+O bands of tellurite glasses doped with Nd3+/Tm3+ and Ag nanoparticles (NPs) was investigated. The tellurite glasses were prepared by melt-quenching and heat-treated techniques. Under the excitation of 808 nm laser, Nd3+/Tm3+ doped tellurite glasses produced three NIR luminescence bands of 1.33, 1.47 and 1.85 μm, originating from Nd3+:4F3/2→4I13/2, Tm3+:3H4→3F4 and Tm3+:3F4→3H6 transitions respectively. Interestingly, a broadband luminescence spectrum ranging from 1280 to 1550 nm with the FWHM (full width at half maximum) about 201 nm was obtained due to the overlapping of the first two NIR bands. Further, the peak intensity of this broadband luminescence was increased by 75% after the introduction of Ag NPs with diameter in 10–20 nm. The analysis of fluorescence decay shows that compared with the enhanced local electric field, the energy transfer from Ag species to Nd3+ and Tm3+ ions plays a major role in luminescence enhancement. The findings in this work indicate that tellurite glass co-doped with Nd3+/Tm3+ and Ag NPs is a potential gain material applied in the S+E+O-band photonic devices.

Luminescence enhancement of Cr3+ doped garnet phosphor for high-performance LED towards smart NIR light source

Cr3+ doped phosphor shows great potential for near-infrared (NIR) light-emitting diodes (LED), but it suffers from low quantum efficiency and poor thermal stability. Herein, a novel Cr3+ doped broadband NIR garnet Ca3Sc2Ge3O12 phosphor was developed. The multisite structure of the emission band is investigated by site-selective spectroscopy and is attributed to the octahedral Cr3+ perturbed by defects. Moreover, we propose different strategies to enhance the luminescence of the phosphor, including enhancement of crystallinity and elimination of defects. Compared with the initial sample, the emission intensity of the optimized phosphor is improved for 8.6 times. The optimal Ca3Sc2Ge3O12: 0.06Cr3+ phosphor exhibits excellent thermal stability. At 423 K, the integral emission intensity of the optimal sample remains 94.7% of that at room temperature. Finally, high-performance NIR LED was fabricated using a blue LED and the title phosphor. The packaged LED lamp has high radiance (109.3 mW@300 mA) and photoelectric efficiency (15.96%@40 mA). Our study not only provides a boulevard for enhancing the luminescence of Cr doped NIR phosphor, but also gives a new perspective for understanding the multisite luminescence of Cr3+ in garnet host.

Synthesis of Platinum(II)-Containing Block Copolymers: Luminescence Enhancement and Controllable Self-Assembly.

In this work, a novel class of diblock polymer ligands, poly(ethylene oxide)-block-polystyrenes end-functionalized with 2,6-bis(benzimidazol-2'-yl)pyridine (bzimpy), have been synthesized and their coordination reactions with K2PtCl4 have created platinum(II)-containing diblock copolymers. They emit red phosphorescence in both THF-water and 1,4-dioxane-n-hexane mixed solvents, arising from Pt(II)···Pt(II) and/or π-π stacking interactions between the planar [Pt(bzimpy)Cl]+ units. Correspondingly, the block copolymers demonstrate a solvent-tunable self-assembly behavior to controllably generate vesicles and worms with core-shell-corona architectures. In these hierarchical nanostructures, the planar [Pt(bzimpy)Cl]+ blocks are associated together to form cores driven by Pt(II)···Pt(II) and/or π-π stacking interactions. Such cores are completely isolated by PS shells, which are further encapsulated by PEO coronas. It should be highlighted here that diblock polymers as polymeric ligands are coupled with phosphorescence platinum(II) complexes, representing a novel approach to create functional metal-containing polymer materials with hierarchical architectures.

Improved 2 µm broadband luminescence in Tm3+/Ho3+ doping tellurite glass.

Tm3+/Ho3+ doping tellurite glasses (TeO2-ZnO-La2O3) were prepared by applying melt-quenching technique, and the ∼2.0 µm band luminescence characteristics were examined. A broadband and relatively flat luminescence at 1600 to 2200 nm was observed in the tellurite glass co-doped by 1.0 mol% Tm2O3 and 0.085 mol% Ho2O3 under the excitation of 808 nm laser diode (LD), which is the result of spectral overlapping of 1.83 µm band of Tm3+ ions and 2.0 µm band of Ho3+ ions. Further, about 103% enhancement was acquired after the introduction of 0.1 mol% CeO2 and 7.5 mol% WO3 at the same time, which is primarily caused by the cross-relaxation between Tm3+ and Ce3+ ions together with the enhanced energy transfer from the Tm3+:3F4 level to Ho3+:5I7 level due to the increase in phonon energy. Spectral characteristics associated with the radiative transition of Ho3+ and Tm3+ ions on the basis of Judd-Ofelt theory, and the fluorescence decay behaviors after the addition of Ce3+ ions and WO3 component were analyzed to understand the broadband and luminescence enhancement. The findings in this work indicate that tellurite glass with optimal Tm3+-Ho3+-Ce3+ tri-doping combination and appropriate amount of WO3 is a prospective candidate for broadband optoelectronic devices operated in the infrared bands.

Effect of Substituents with the Different Electron-Donating Abilities on Optoelectronic Properties of Bipolar Thioxanthone Derivatives.

The synthesis and optoelectronic properties of four simple-structure thioxanthone derivatives employing thioxanthone as an acceptor unit, coupled with moieties having very different electron-donating abilities such as phenoxazine, 3,6-di-tert-butylcarbazole, 3,7-di-tert-butylphenothiazine, or 2,7-di-tert-butyl-9,9-dimethylacridane, are reported. The compounds form molecular glasses with glass transition temperatures reaching 116 °C. Ionization potentials of the compounds estimated by photoelectron emission method range from 5.42 to 5.74 eV. Thioxanthone derivatives containing 3,6-tert-butylcarbazole or 2,7-di-tert-butyl-9,9-dimethylacridane moieties with weak electron-donating strengths were characterized by bipolar charge transport with relatively close hole and electron mobility values of 6.8 × 10-5/2.4 × 10-5 and 3.1 × 10-5/4.6 × 10-6 cm2/(V s) recorded at 3.6 × 105 V/cm. The other compounds demonstrated hole-transporting properties. The films of thioxanthones containing phenoxazine or 2,7-di-tert-butyl-9,9-dimethylacridane moieties showed efficient thermally activated delayed fluorescence with a photoluminescence quantum yield of up to 50% due to the solid-state luminescence enhancement. Organic-light-emitting diodes containing the synthesized compounds as emitters showed very different external quantum efficiencies (0.9-10.3%) and blue, sky blue, green, or yellow electroluminescence colors, thus reflecting the effects of donor substituents.

Luminescence enhancement of gold nanoclusters hydrogel through co-assembly strategy and its application for detection

Gold nanoclusters (AuNCs) with ultrasmall size have attracted enormous interest due to their unique luminescent properties. Especially, luminescent AuNCs-based hydrogel with three-dimensional (3D) structures is valuable. Herein, hydrogel with effective enhancement of emission (QY increased from 0.45% to 14.6%) is reported through the co-assembly of AuNCs stabilized by 4,6-diamino-2-pyrimidinethiol (DPT) with citric acid (CA) and Al3+. With the formation of hydrogel, the microstructures of DPT-AuNCs changed from nanofibers into microdisks. X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra and Fourier transform infrared (FT-IR) reveal that CA is crucial for the emission enhancement of NCs and Al3+ is benefit for the gelation of NCs. Furthermore, the obtained luminescent hydrogel could be used as a selective sensor for Fe3+/ascorbic acid (AA) through the “switch off/on” of luminescence and may find an application in information security. This study offers a convenient strategy for building AuNCs-based luminescent hydrogel through co-assembly method, and presents potential applications as functional materials.

Boosting Trapping in Dark Mode and Emission in Bright Mode using a Quad‐Nanohole

AbstractSingle‐emitter luminescence is attractive for various applications, including single‐molecular biology, super‐resolution optical imaging, and single‐photon sources. Optical trapping as a particle positioning method is promising for enhancing luminescence by a precise matching of the nanoemitter to the sub‐wavelength mode volume of the photonic structure. Simultaneously satisfying the requirement of both luminescence and trapping enhancement, however, is challenging. Here, stable optical trapping and the in situ excitation of highly bright photoluminescence of a single up‐conversion nanoparticle (UCNP) are demonstrated. A quad‐nanohole structure with two bright‐field modes for enhanced excitation and emission of the UCNP, as well as a dark‐field mode for enhanced optical trapping is designed. It is experimentally demonstrated that the photoluminescence of the UCNP optically trapped in the quad‐nanohole is enhanced by a factor of 87 (as compared to a UCNP trapped in the single nanohole), and this enhancement factor surpasses that from a bowtie nanohole—one of the “gold standards” for local field enhancement. This work provides a route to assemble super‐bright single‐emitter luminescence by optical trapping.

Upconversion Luminescence from Sol-Gel-Derived Erbium- and Ytterbium-Doped BaTiO3 Film Structures and the Target Form

Sol-gel technology has attracted attention in the fabrication of diverse luminescent materials and thin film structures, with forms that range from powders to microcavities. The optical properties of sol-gel-derived structures depend on the sol composition, deposition, and heat treatment conditions, as well as on the film thicknesses and other factors. Investigations on the upconversion luminescence of lanthanides in film structures and materials are also ongoing. In this study, we synthesized three different types of materials and film structures using the same sol, which corresponded to a Ba0.76Er0.04Yb0.20TiO3 xerogel, as follows: (a) the target form, which used the explosive compaction method for sol-gel-derived powder; (b) single-layer spin-on xerogel films annealed at 450 and 800 °C; and (c) microcavities with an undoped SiO2/BaTiO3 Bragg reflector surrounding a Ba0.76Er0.04Yb0.20TiO3 active layer. The BaTiO3:(Er,Yb)/SiO2 microcavity exhibited an enhancement of the upconversion luminescence when compared to the BaTiO3:(Er,Yb) double-layer film fabricated directly on a crystalline silicon substrate. The reflection spectra of the BaTiO3:(Er, Yb)/SiO2 microcavity annealed at 800 °C demonstrated a deviation of the maxima of the reflection within 15% for temperature measurements ranging from 26 to 120 °C. From the analyses of the transmission and reflection spectra, the optical band gap for the indirect optical transition in the single layer of the BaTiO3:(Er,Yb) spin-on film annealed at 450 °C was estimated to be 3.82 eV, while that for the film annealed at 800 °C was approximately 3.87 eV. The optical properties, upconversion luminescence, and potential applications of the BaTiO3:(Er,Yb) sol-gel-derived materials and structures are discussed in this paper.

Excitation Wavelength‐Dependent Upconversion Luminescence Enhancement in Tm3+‐Doped LiErF4@LiYF4 System Under High Pressure

AbstractLocal structural engineering is an endogenous approach to modulate upconversion luminescence (UCL) from upstream to meet the needs of specific application scenarios. Herein, high pressure is utilized as a means to modulate the local structure, and the designed LiErF4:0.5%Tm3+@LiYF4 (Er:Tm@Y) nanoparticles with fast energy transfer rates, abundant cross‐relaxation processes, and multiple near‐infrared wavelengths (808, 980, 1530 nm) excitation properties are tailored as local structure‐sensitive hosts. A unique excitation wavelength‐dependent UCL enhancement of Er:Tm@Y upconversion nanoparticles is observed by pressure‐induced local structure distortions. When the pressure of ≈6 GPa is applied, the UCL is enhanced by a factor of 2.6 at 980 nm excitation only. After pressure release, the luminescence diminishes and recovers. Density functional theory calculations show that the symmetry distortion of the LiErF4 crystal reaches a maximum at pressurization to 6 GPa, while a new Er‐4f state emerges, greatly reducing the bandgap from 8.3 to 5.7 eV. Comparative experiments demonstrate that the local symmetry distortion caused by 0.5%Tm3+ doping and the different energy transfer patterns of Er3+ to Tm3+ at different excitations are responsible for this wavelength‐dependent luminescence enhancement.

Ab Initio Site‐Selective Occupancy and Luminescence Enhancement in Broadband NIR Emitting Phosphor Mg7Ga2GeO12:Cr3+

AbstractCr3+ activated near‐infrared (NIR) phosphors are getting unprecedented attention to fabricate the broad band NIR light emitting diodes (NIR‐LEDs) for nondestructive detection, bio‐imaging, and night vision. However, it remains a major challenge to obtain ultrabroadband NIR emitting phosphor with excellent quantum yield (QY). Here, a broadband NIR emitting phosphor Mg7Ga2GeO12:Cr3+ (MGGO: Cr3+) ranging from 600 to 1300 nm with an outstanding QY (93%) and large full width of half maximum (FWHM = 226 nm) is developed, in which the site occupancy tendency of Cr3+ in MGGO host is discussed in detail through combining the structure optimization and the first‐principles theory calculation with luminescent properties at low temperature. After that, the emission intensity of MGGO:Cr3+ is improved through partial substitution of Mg2+ by alkaline‐earth ions Ca2+, Sr2+, or Ba2+, and the luminescence enhancement mechanism is also investigated. Furthermore, the NIR pc‐LED device is fabricated by combining 450 nm blue LED chip with the brightest phosphor MGGO:Cr3+/Ba2+, and its potential applications are evaluated in the field of nondestructive detection, night vision, and bio‐imaging.

Luminescence Enhancement and Temperature Sensing Properties of Hybrid Bismuth Halides Achieved via Tuning Organic Cations

Bismuth-halide-based inorganic-organic hybrid materials (Bi-IOHMs) are desirable in luminescence-related applications due to their advantages such as low toxicity and chemical stability. Herein, two Bi-IOHMs of [Bpy][BiCl4(Phen)] (1, Bpy = N-butylpyridinium, Phen = 1,10-phenanthroline) and [PP14][BiCl4(Phen)]·0.25H2O (2, PP14 = N-butyl-N-methylpiperidinium), containing different ionic liquid cations and same anionic units, have been synthesized and characterized. Single-crystal X-ray diffraction reveals that compounds 1 and 2 crystallize in the monoclinic space group of P21/c and P21, respectively. They both possess zero-dimensional ionic structures and exhibit phosphorescence at room temperature upon excitation of UV light (375 nm for 1, 390 nm for 2), with microsecond lifetime (24.13 μs for 1 and 95.37 μs for 2). Hirshfeld surface analysis has been utilized to visually exhibit the different packing motifs and intermolecular interactions in 1 and 2. The variation in ionic liquids makes compound 2 have a more rigid supramolecular structure than 1, resulting in a significant enhancement in photoluminescence quantum yield (PLQY), that is, 0.68% for 1 and 33.24% for 2. In addition, the ratio of the emission intensities for compounds 1 and 2 shows a correlation with temperature. This work provides new insight into luminescence enhancement and temperature sensing applications involving Bi-IOHMs.

Role of Boron in Assisting the Super-Enhancement of Emissions from Carbon-Implanted Silicon.

The super enhancement of silicon band edge luminescence when co-implanted with boron and carbon is reported. The role of boron in the band edge emissions in silicon was investigated by deliberately introducing defects into the lattice structures. We aimed to increase the light emission intensity from silicon by boron implantation, leading to the formation of dislocation loops between the lattice structures. The silicon samples were doped with a high concentration of carbon before boron implantation and then annealed at a high temperature to activate the dopants into substitutional lattice sites. Photoluminescence (PL) measurements were performed to observe the emissions at the near-infrared region. The temperatures were varied from 10 K to 100 K to study the effect of temperature on the peak luminescence intensity. Two main peaks could be seen at ~1112 and 1170 nm by observing the PL spectra. The intensities shown by both peaks in the samples incorporated with boron are significantly higher than those in pristine silicon samples, and the highest intensity in the former was 600 times greater than that in the latter. Transmission electron microscopy (TEM) was used to study the structure of post-implant and post-anneal silicon sample. The dislocation loops were observed in the sample. Through a technique compatible with mature silicon processing technology, the results of this study will greatly contribute to the development of all Si-based photonic systems and quantum technologies.

Enhancement of luminescence, thermal stability and quantum efficiency with Ce3+ co-doped SrMg1·06Al9·94O17:Tb3+ phosphor

In this study, the photoluminescence properties of a series of SrMg1·06Al9·94O17 (SMAO):Ce3+, Tb3+, and SMAO:Tb3+ phosphors were investigated. At an excitation wavelength of 230 nm, the SMAO:Tb3+ phosphor emitted green light at 544 nm. When Ce3+ ions were co-doped into SMAO:Tb3+, the excitation band red-shifted from 230 to 269 nm, and the emission intensity was enhanced up to approximately 28 times compared with that of Ce3+-free SMAO:Tb3+ because of the efficient energy transfer from Ce3+ → Tb3+ in the SMAO host. Moreover, with the introduction of Ce3+, the thermal stability of the phosphors improved significantly. The luminescence intensity of the SMAO:3 mol%Tb3+ phosphor at 450 K was approximately 47% of that at room temperature. With the co-doping of Ce3+ ions, the emission intensity at 450 K was as high as 67%. The internal quantum efficiency (IQE) of SMAO:3 mol%Tb3+, 3 mol%Ce3+ increased to 55.14%. The SMAO:Tb3+,Ce3+ phosphors have potential applications in solid-state lighting.

Boosting the 1540 nm near-infrared luminescence of Er3+ doped double perovskites via cross-relaxation and energy transfer

Rare earth (RE) doped lead-free double perovskites (DPs) are potential near-infrared (NIR) light source materials due to their non-toxicity, simple preparation and low price. In this work,Cs2Ag0.1Na0.9BiCl6 DPs were chosen as matrix materials and different RE ions (Eu3+/Yb3+/Tb3+) were co-doped with Er3+ ions to study the effective ways to further enhance the NIR luminescence of Er3+ at 1540 nm in DPs. It found that double-doping (Eu–Er, Tb–Er, and Yb–Er) can improve the 1540 nm emission of Er3+ in DPs through cross-relaxation (CR) and energy transfer (ET), respectively. For tri-doped samples (DPs-Yb-Eu-Er and DPs-Yb-Tb-Er), the CR process between the Eu3+ (Tb3+) and Er3+ ions and the ET process from Yb3+ to Er3+ ions enhance synergically the luminescence of Er3+ at 1540 nm. Under excitation at 365 and 980 nm, the luminescence enhancement of DPs-Yb-Eu-Er at 1540 nm is 6.2 and 45 times, respectively, compared with that of DPs-Er. At the excitation of 365 nm, the photoluminescence quantum yield (PLQY) of DPs-Yb-Eu-Er is 18.2%, which is the maximum efficiency recorded reported so far for micron level DPs. Finally, DPs-Yb-Eu-Er was embedded into a polymethyl methacrylate (PMMA) polymer matrix to form a NIR light-emitting diode (LED) device. Good night vision imaging and tissue penetration experiments were performed under the irradiation of this NIR LED. This work provided a new method for the design of RE doped lead-free DPs with effective NIR emission.

Upconversion luminescence enhancement of NaGdF4:Er3+/Yb3+/Al3+ nanorods through tuning Al2O3 layer in a hybrid photonic-plasmonic-dielectric structure

Surface plasmon resonance and photonic crystals (PCs) effect are effective methods for improving upconversion luminescence (UCL) for upconversion nanoparticles. In this work, PCs/Ag/Al2O3/UC hybrid structure is presented to enhance UCL of NaGdF4:Er3+/Yb3+/Al3+ nanorods through tuning the thickness of the Al2O3 layer. The optical and luminescence properties were studied and compared with those of UC and PCs/Ag/UC hybrid, it is shown that the thickness of Al2O3 layer has a significant effect on fluorescence intensity, outstanding upconversion luminescence enhancement and the green-to-red intensity ratios have been achieved at 980 nm excitation. The maximum enhancement factors of the red and green emission were obtained for the sample with 10 nm Al2O3 layer, respectively. The mechanism of UCL enhancement for PCs/Ag/Al2O3/UC hybrid structure was discussed.

Luminescence Enhancement of CsMnBr3 Nanocrystals through Heterometallic Doping

The absorption and photoluminescence (PL) of CsMnBr3 with Mn(II) in octahedral crystal fields are extremely weak due to a d-d forbidden transition. Herein, we introduce a facile and general synthetic procedure that can prepare undoped and heterometallic doped CsMnBr3 NCs at room temperature. Importantly, both PL and absorption of CsMnBr3 NCs were significantly improved after doping a small amount of Pb2+ (4.9%). The absolute photoluminescence quantum yield (PL QY) of Pb-doped CsMnBr3 NCs is up to 41.5%, 11-fold higher than undoped CsMnBr3 NCs (3.7%). The PL enhancement is attributed to the synergistic effects between [MnBr6]4- units and [PbBr6]4- units. Furthermore, we verified the similar synergistic effects between [MnBr6]4- units and [SbBr6]4- units in Sb-doped CsMnBr3 NCs. Our results highlight the potential of tailoring luminescence properties of manganese halides through heterometallic doping.

Enhancement of Luminescence of PET Films after Swift Heavy Ion Irradiation

The novelty of the study is that the ordering that occurs in a PET film under the action of SHI irradiation manifests itself as an increase in the integral intensity of intrinsic luminescence. The Urbach behaviour of the red shift of the absorption edge is used as a baseline for further analysis of experimental optical transmission spectra of PET films irradiated by swift heavy ions (SHI) previously published by the authors. Negative deviations of the experimental spectra from the Urbach baseline in the visible and UV parts of the spectrum are attributed to enhanced by SHI irradiation intrinsic luminescence. The observed dependence of the integral intensity of luminescence of irradiated PET films on the SHI fluence and ion charge provides further confirmation of the presence of SHI-induced ordering of the molecular structure in SHI latent tracks.