Predominant Emission Research Articles

Near-ultraviolet excited Tm3+ and Dy3+ ions co-doped barium lanthanum silica oxide phosphors for white-light applications

Nowadays, trivalent rare-earth ions activated inorganic luminescent materials have been widely investigated owing to their important applications in solid-state lighting field. Tm3+ and Dy3+ ions single- or co-doped Ba3La6(SiO4)6 (BLSO) phosphor materials for white light application were synthesized by a citrate-based sol-gel method. The prepared samples were examined by X-ray diffraction (XRD), scanning electron microscopy and Fourier-transform infrared spectroscopy to analyze the phase purity, surface morphology and existence of functional groups, respectively. The XRD pattern confirmed that the BLSO host lattice exhibited a hexagonal crystal structure with P63/m (176) space group, which is well indexed with standard JCPDS data. From photoluminescence results, the BLSO:Tm3+ phosphors exhibited purplish blue emission at 453 nm (1D2→3F4) and the BLSO:Dy3+ phosphors showed predominant yellow emission at 575 nm (4F9/2 → 6H13/2) compared to their shoulder blue emission at 479 nm (4F9/2 → 6H15/2), indicating that the Dy3+ ions occupied lattice sites with low inversion symmetry. The determined Commission Internationale de I’Eclairage (CIE) (0.3391, 0.3302) values for the Tm3+/Dy3+ co-doped BLSO phosphors were near to the standard sun light CIE values (0.33, 0.33) under near-ultraviolet (364 nm) excitation. The energy transfer process from Dy3+ to Tm3+ ions was discussed and it was proved by their corresponding decay curves. Additionally, thermal study was carried out for the optimized phosphor and it maintained superior thermal PL properties.

Cathodoluminescence and thermoluminescence of ZnB2O4:Eu3+ phosphors prepared via wet-chemical synthesis

In present work, a series of Eu doped zinc borate, ZnB2O4, phosphors prepared via wet chemical synthesis and their structural, surface morphology, cathodoluminescence (CL) and thermoluminescence (TL) properties have been studied. Phase purity and crystal structure of as-prepared samples are confirmed by X-ray diffraction measurements (XRD) and they were well consistent with PDF card No. 39-1126, indicating the formation of pure phase. The thermoluminescence (TL) behaviors of Eu activated ZnB2O4 host lattice are studied for various beta doses ranging from 0.1 to 10 Gy. The high-temperature peak of Eu activated sample located at 192 °C exhibited a linear dose response in the range of 0.1–10 Gy. Initial rise (IR) and peak shape (PS) methods were used to determine the activation energies of the trapping centres. The effects of the variable heating rate on TL behaviour of Eu activated ZnB2O4 were also studied. When excited using an electron beam induced light emission (i.e cathodoluminescence, CL) at room temperature (RT), the as-prepared phosphors generate reddish-orange color due to predominant emission peaks of Eu3+ ions located at 576–710 nm assigned to the 5D0→7FJ (J=1,2,3, and 4) transitions. The maximum CL intensity for Eu3+ ions at 614 nm with transition 5D0→7F2 was reached Eu3+ concentration of 5 mol%; quenching occurred at higher concentrations. Strong emission peak for Eu3+ ions at 614 nm with transition 5D0→7F2 is observed. The CL experimental data indicate that ZnB2O4:Eu3+ phosphor as an orange-red emitting phosphor may be promising luminescence materials for the optoelectronic applications.

Physico-chemical characterization and in vitro inflammatory and oxidative potency of atmospheric particles collected in Dakar city's (Senegal)

Exposure to atmospheric pollutants has been recognized as a major risk factor of respiratory and cardiovascular diseases. Fine particles (PM2.5) and a coarser fraction (PM>2.5) sampled at an urban site in Dakar (HLM), characterized by high road traffic emissions, were compared with particles sampled at a rural area, Toubab Dialaw located about 40 km from Dakar. The physicochemical characteristics of samples revealed that PMs differ for their physical (surface area) and chemical properties (in terms of CHN, metals, ions, paraffins, VOCs and PAHs) that were 65–75% higher in urban samples. Moreover the fine PMs contain higher amounts of anthropogenic related pollutants than the PM>2.5 one. These differences are sustained by the ratios reported for the analysed PAHs which suggest as predominant primary emission sources vehicle exhausts at urban site and biomass combustion at the rural site. The inflammatory response and the oxidative damages were evaluated in BEAS-2B cells by the quantification of 4 selected inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8) and of total carbonylated proteins and the oxidative DNA adduct 8-OHdG after 8 or 24 h exposure. In accordance with the different sources and different physical and chemical properties, the inflammatory response and the oxidative damages were found higher in bronchial cells exposed to urban PMs. These data confirm the importance, also for West African countries, to evaluate the correlation between PM physico-chemical properties and potential biological impacts.

White-light emitting (Y,Gd)PO4:Dy3+ microspheres: Gd3+ mediated morphology tailoring and selective energy transfer and correlation of photoluminescence behaviors

Well-dispersed and one micron-sized spheres of tetragonal Y/Gd/Dy ternary phosphate have been facilely synthesized via microwave-assisted homogeneous precipitation. The spheres are polycrystalline, and the particle size gradually decreases with increasing Gd3+ content. Excessive doping of Gd3+ leads to the appearance of hexagonal-structured rods on particle surface. The Y/Gd/Dy ternary phosphor exhibits two predominant emission peaks, with a blue one at ∼483 nm and a yellow one at ∼575 nm, thus yielding a white light-emitting color. Mainly due to the efficient energy transfer, incorporation of Gd3+ resulted in enhanced luminescence intensity, with nearly a 1000% increase at 575 nm. Because the selective energy transfer from Gd3+ to the 4F9/2→6H13/2 transition of Dy3+ takes the dominant role, more remarkable enhanced intensity at ∼575 nm than that at ∼483 nm was observed. Enhanced emission intensity, shorter lifetimes, and almost the same CIE coordinates were observed at a higher calcination temperature.

Study of Ti/Al/Ni Ohmic Contacts to p-Type Implanted 4H-SiC

This work reports on the electrical and microstructural properties of Ti/Al/Ni contacts to p-type implanted 4H-SiC obtained by rapid thermal annealing of a metal stack of Ti (70 nm)/Al (200 nm)/Ni (50 nm). The contact characteristics were monitored at increasing value of the annealing temperature. The Ohmic behavior of the contact, with a specific contact resistance value of 2.3×10-4 Ω·cm2, is obtained for an annealing at 950 °C. The structural analyses of the contact, carried out by XRD and TEM, reveal the occurrence of reactions, with the detection of the Al3Ni2 and AlTi phases in the upper part of the contact and of an epitaxially oriented TiC layer at the interface. These reactions are considered the key factors in the formation of an Ohmic contact in our annealed Ti/Al/Ni system. The temperature-dependence study of the electrical characteristics reveals a predominant thermionic field emission (TFE) mechanism for the current conduction through the contact, with a barrier height of 0.56 eV.

Structural and photoluminescent elucidation of the efficient green emitting erbium doped BaY2ZnO5 nanophosphor for light emitting materials

Erbium doped BaY2ZnO5 nanophosphor was synthesized by solution combustion approach using urea as an organic fuel. The spherical shaped phosphors in the nano dimension (40–70 nm) were characterized by X-ray diffraction, transmission electron microscopy and photoluminescence spectroscopy. XRD studies reveal that in BaY1.92Er0.08ZnO5 nano phosphor substitution of Y3+ ion by Er3+ ion does not lead to any major structural changes in the host lattice and confirms single phased nanophosphor crystallized in orthorhombic lattice with Pbnm (62) space group. The excitation spectrum depicts that this nanophosphor can be effectively excited by NUV light, resulting characteristic emissions from 2H9/2, 2H11/2, 4S3/2 to 4I15/2 transition level with predominant green emission at 549 nm. Concentration dependent luminescence tendency reveals optimized concentration for maximum luminescence as 4 mol%. A larger value of critical distance (14.38 A) is found responsible for non-radiative energy transfer occurring via dipole–quadrupole (d–q) interactions leading to concentration quenching. Luminescence decay kinetics and color coordinates (0.283, 0.616) has also been evaluated. The findings of the study support the application of this nanophosphor in the field of NUV excited tricolor based PC-white LED systems.

Structural, dielectric and photoluminescence properties of Nd3 + doped Li2O-LiF-B2O3-ZnO multifunctional optical glasses for solid state laser applications

Lithium fluoro zinc borate (LBZ) glasses doped with Nd3+ ions at distinct concentrations (0.3, 0.5, 1 & 1.5mol%) were prepared using melt quenching technique. Structural, thermal and compositional studies of these glasses were carried out by XRD, TG-DTA and FTIR analysis respectively. The properties of dielectric studies such as dielectric constant and dielectric loss have been studied systematically as a function of frequency. The ionic conductivity of Nd3+: LBZ doped glasses have been found to be more than the conductivity of the host LBZ glass and the optimized concentration of 0.5mol% Nd3+: LBZ glass exhibits high ionic conductivity. Photoluminescence proerties of obtained glasses were systematically analyzed. J-O intensity Ωλ (λ=2, 4, 6) parameters have been evaluated from the absorption spectrum of 0.5mol% Nd3+: LBZ glass and they were used to estimate the parameters such as radiative lifetime (τR), transition probability (A), branching ratios (βR) and spectroscopic quality factor (χ) for the major emission transitions. Predominant NIR emission at 1062nm (4F3/2→4I11/2) is observed under the excitation of 741nm (4I9/2→4F7/2) along with other two moderately less intense emission peaks at 897nm (4F3/2→4I9/2) and 1332nm (4F3/2→4I13/2). Experimental lifetime for the level 4F3/2 has been compared with radiative lifetime obtained through J-O parameters. The decay lifetimes dynamics and non-radiative transition rate have been systematically evaluated. These Nd3+ doped glasses could be suggested as promising candidates for 1.06μm laser applications and solid state battery applications.

Investigation of NIR-to-red upconversion luminescence mechanism in Y2O3:Er3+,Yb3+ and the effect of co-doping Zn in the matrix

We studied composite ZnO:Y2O3 matrix for upconversion luminophore pair Er:Yb using near IR light excitation. Uni-phase crystalline nanoparticles were produced up to a 4% co-doped ZnO in Y2O3. In ZnO:Y2O3 co-host matrix, Er(2%):Yb(10%) pair emits strong red luminescence. Doping 4% ZnO into the matrix enhances the luminescence by ~ 2.5 times. The mechanisms for the predominant red emission in the presence and absence of Zn ions were studied. An energy back transfer (EBT) process from Er to Yb is the main pathway for the intense red emission under NIR excitation although other mechanisms, e.g. Er-Er cross relaxation (CR), may also contribute to the red emission. The Er-Yb EBT process brings the Er ion from the green emission state to the intermediate 4I13/2 state, which further absorbs a near IR photon and jumps to the red emission state. The introduction of ZnO into Y2O3 matrix does not interfere with this process significantly. Thus, the enhancement of luminescence is mainly caused by the breaking of the symmetry around Er3+ ions due to the Y-to-Zn substitution, which favors the f-f electric dipole transitions that are forbidden in centrosymmetric environment.

Synthesis of Cu and Ce co-doped ZnO nanoparticles: crystallographic, optical, molecular, morphological and magnetic studies

AbstractIn the present research work, crystallographic, optical, molecular, morphological and magnetic properties of Zn1-xCuxO (ZnCu) and Zn1-x-yCeyCuxO (ZnCeCu) nanoparticles have been investigated. Polyvinyl alcohol (PVA) coated ZnCu and ZnCeCu nanoparticles have been synthesized by chemical sol-gel method and thoroughly studied using various characterization techniques. X-ray diffraction pattern indicates the wurtzite structure of the synthesized ZnCu and ZnCeCu particles. Transmission electron microscopy analysis shows that the synthesized ZnCu and ZnCeCu particles are of spherical shape, having average sizes of 27 nm and 23 nm, respectively. The incorporation of Cu and Ce in the ZnO lattice has been confirmed through Fourier transform infrared spectroscopy. Room temperature photoluminescence spectra of the ZnO doped with Cu and co-doped Ce display two emission bands, predominant ultra-violet near-band edge emission at 409.9 nm (3 eV) and a weak green-yellow emission at 432.65 nm (2.27 eV). Room temperature magnetic study confirms the diamagnetic behavior of ZnCu and ferromagnetic behavior of ZnCeCu.

Crystal structure characterization and up-conversion luminescent properties of BaIn2O4 phosphor

Er3+ / Yb3+ doped BaIn2O4 up-conversion (UC) phosphors are synthesized and their UC luminescent properties are characterized. BaIn2O4 has P21/c space group but Rietveld refinement suggests it has twice smaller cell parameter (a = 10.3975Å, b = 5.8295Å, c = 14.4457Å) and volume than previous reported structure. Refinement also reveals Er3+/Yb3+ replaces In3+ ions in lattice because of the existence of InO6 octahedra. In these BaIn2O4 phosphors, co-doping with Yb3+ ions changes the predominant UC emission from green ( 2H11/2, 4S3/2 → 4I15/2 of Er3+) to red (about 665nm, 4F9/2 → 4I15/2 of Er3+). By controlling of Er3+/Yb3+ concentrations, the BaIn2O4 phosphors have the potential of generating various UC spectra and color tunability. The pumping powers study shows two-photon process in these phosphors.

Luminescent Eu3+-doped transparent alumina ceramics with high hardness

The Eu3+-doped transparent aluminas were prepared by wet shaping technique followed by pressure-less sintering and hot isostatic pressing. The effect of dopant amount on microstructure, real in-line transmission (RIT), photoluminescence (PL) properties, hardness and fracture behaviour was studied. The RIT decreased with increasing amount of the dopant. The PL emission spectra of Al2O3:Eu3+ ceramics exhibited predominant red light emission with the highest intensity (under 394nm excitation) for material containing 0.125at.% of Eu3+ and colour coordinates (0.645, 0.355) comparable with commercial red phosphors. The doping resulted in hardness increase from 26.1GPa for undoped alumina to 27.6GPa for Eu-doped sample. The study of fracture surfaces showed predominantly intergranular crack propagation micro-mechanism.

Energy transfer (In3+ → Eu3+) based Polyvinyl Alcohol polymer composites for bright red luminescence

A prominent sensitization effect of In3+ ions is observed in In3++Eu3+: PVA polymer composites under UV excitation. Consequently, it enhances the red emission performance of Eu3+ ions in PVA system. We have successfully synthesized Eu3+: PVA, In3+: PVA and In3++Eu3+: PVA polymer films by traditional solution casting method. The structural and ion-polymer interaction studies have been analyzed from XRD and FTIR spectral profiles. Eu3+ doped PVA polymer composites are exhibited a red emission at 619 nm (5D0→7F2) under 396 nm (7F0→5L6) of excitation. Upon co-doping with In3+ ions in different concentrations to the Eu3+: PVA polymer film, it exhibits predominant red emission than singly doped Eu3+: PVA under 396 nm of excitation due to energy migration from In3+ to Eu3+. Successful emission photons of In3+ ions are collectively absorbed by the Eu3+ ions which lead the improvement of red emission. Optimized sensitization concentration of the In3+ ions has been found to be 0.01 wt%. Possible energy migration phenomenon is elucidated by several fluorescent dynamics. The energy transfer process is substantiated by lifetime decay analysis and overlapped spectral studies. The Commission International de I-Eclairage chromaticity coordinates were calculated. The quantum efficiencies of the Eu3+ ions and In3+ ions in singly doped and co-doped polymer systems have been evaluated. From these results, these co-doped In3++Eu3+: PVA composite polymer films might be proposed as encouraging candidates for bright red fluorescent materials for several photonic applications.

Highly Efficient Green-Emitting Phosphors Ba2Y5B5O17 with Low Thermal Quenching Due to Fast Energy Transfer from Ce3+ to Tb3.

This paper demonstrates a highly thermally stable and efficient green-emitting Ba2Y5B5O17:Ce3+, Tb3+ phosphor prepared by high-temperature solid-state reaction. The phosphor exhibits a blue emission band of Ce3+ and green emission lines of Tb3+ upon Ce3+ excitation in the near-UV spectral region. The effect of Ce3+ to Tb3+ energy transfer on blue to green emission color tuning and on luminescence thermal stability is studied in the samples codoped with 1% Ce3+ and various concentrations (0-40%) of Tb3+. The green emission of Tb3+ upon Ce3+ excitation at 150 °C can keep, on average, 92% of its intensity at room temperature, with the best one showing no intensity decreasing up to 210 °C for 30% Tb3+. Meanwhile, Ce3+ emission intensity only keeps 42% on average at 150 °C. The high thermal stability of the green emission is attributed to suppression of Ce3+ thermal de-excitation through fast energy transfer to Tb3+, which in the green-emitting excited states is highly thermally stable such that no lifetime shortening is observed with raising temperature to 210 °C. The predominant green emission is observed for Tb3+ concentration of at least 10% due to efficient energy transfer with the transfer efficiency approaching 100% for 40% Tb3+. The internal and external quantum yield of the sample with Tb3+ concentration of 20% can be as high as 76% and 55%, respectively. The green phosphor, thus, shows attractive performance for near-UV-based white-light-emitting diodes applications.

Ambient particulate matter and carbon monoxide at an urban site of India: Influence of anthropogenic emissions and dust storms

Continuous measurements of PM2.5, PM10 and CO were conducted at an urban site of Udaipur in India from April 2011 to March 2012. The annual mean concentrations of PM2.5, PM10 and CO were 42 ± 17 μg m−3, 114 ± 31 μg m−3 and 343 ± 136 ppbv, respectively. Concentrations of both particulate and CO showed high values during winter/pre-monsoon (dry) period and lowest in the monsoon season (wet). Local anthropogenic emission and long-range transport from open biomass burning sources along with favourable synoptic meteorology led to elevated levels of pollutants in the dry season. However, higher values of PM10/PM2.5 ratio during pre-monsoon season were caused by the episodes of dust storm. In the monsoon season, flow of cleaner air, rainfall and negligible emissions from biomass burning resulted in the lowest levels of pollutants. The concentrations of PM2.5, PM10 and CO showed highest values during morning and evening rush hours, while lowest in the afternoon hours. In winter season, reductions of PM2.5, CO and PM10 during weekends were highest of 15%, 13% and 9%, respectively. In each season, the highest PM2.5/PM10 ratio coincided with the highest concentrations of pollutants (CO and NOX) indicating predominant emissions from anthropogenic sources. Exceptionally high concentrations of PM10 during the episode of dust storm were due to transport from the Arabian Peninsula and Thar Desert. Up to ∼32% enhancements of PM10 were observed during strong dust storms. Relatively low levels of O3 and NOx during the storm periods indicate the role of heterogeneous removal.

Mn doped zinc silicate nanophosphor with bifunctionality of green-yellow emission and magnetic properties

Luminescent-magnetic bifunctional Mn2+-doped Zn2SiO4 (ZSMn2+) nanophosphor were synthesized by the sol-gel technique and characterized by X-ray diffraction (XRD), UV–vis absorption, transmission electron microscopy (TEM), photoluminescence (PL) and SQUID. The Mn2+-doped effects of zinc silicate (ZS) upon the emission intensity and decay time were investigated under 4.86eV excitation. Mn2+-doped ZS nanophosphor exhibits predominant visible emission under 4.86eV ultraviolet light excitation, and the trend of their color changes from green to yellow are simultaneously realized in single-phase. The ZS nanophosphors exhibit green and yellow luminescence, depending on their crystal structure, which can vary with the preparation conditions. The green peak at at 2.37eV is due to α– phase, while the yellow peak centered at 2.15eV is due to the β– phase. The two phases are diamagnetic at room temperature but become ferromagnetic at 5K. It was found that α-ZSMn2+ phase has a higher saturation than the β-ZSMn2+ phase. The correlation between the optical, structural and magnetic properties of nanophosphor is discussed in detail.

Synthesis and luminescence of Sr2Ta2O7:Pr3+: a novel blue emission, long persistent phosphor

Abstract

Dy3+ and Eu3+ Co-doped NaGdF4 nanofibers endowed with bifunctionality of tunable multicolor luminescence and paramagnetic properties

Luminescent-magnetic bifunctional NaGdF4:Dy3+,Eu3+ nanofibers have been successfully fabricated via the combination of electrospinning followed by calcination with fluorination technique for the first time. The structure, morphologies, luminescence, and magnetic properties of the synthesized nanofibers have been characterized by a variety of techniques. X-ray diffraction (XRD) analysis shows that as-prepared NaGdF4:Dy3+,Eu3+ nanofibers are pure hexagonal structure. Scanning electron microscope (SEM) observations indicate that directly electrospinning-made PVP/[NaNO3+Gd(NO3)3+Dy(NO3)3+Eu(NO3)3] composite nanofibers have smooth surfaces, good dispersion and uniform size, and the surfaces of NaGdF4:Dy3+,Eu3+ nanofibers become rough after calcination and fluorination process. The diameters of composite nanofibers and NaGdF4:Dy3+,Eu3+ nanofibers are respectively 400.19±48.06nm and 245.90±52.10nm. NaGdF4:Dy3+,Eu3+ nanofibers exhibit predominant visible emission under 274nm ultraviolet light excitation and the trend of their color tones changes from blue, cold white, warm white to red by adjusting the molar concentration of Eu3+. In addition, all of the samples exhibit paramagnetic features and the magnetic properties of NaGdF4:Dy3+,Eu3+ nanofibers are tunable by changing the species and doping concentration of RE3+ ions. More importantly, the tunable multicolor luminescence and paramagnetic properties are simultaneously realized in single-phase NaGdF4:Dy3+,Eu3+ nanofibers, which ideally suit to apply in many fields such as solid-state lasers, lighting and displays, magnetic resonance imaging. This design conception and construction strategy developed in this work may provide some new guidance for the synthesis of other rare earth fluorides nanostructures with various morphologies.

Effect of crystalline fraction on upconversion luminescence in Er3+/Yb3+ Co-doped NaYF4 oxyfluoride glass-ceramics

The crystalline fraction were adjusted MgO concentration and the corresponding effect on upconversion (UC) luminescence in Er3+/Yb3+ co-doped NaYF4 oxyfluorode glass-ceramics was investigated. With increase of MgO and the content of Na2O reduced, the internal network structure of the glass became compact, which made the size of NaYF4 nanocrystals unchanged, while the average distance between the nanocrystals increased significantly. Crystal growth is limited with the glass network, keeping the crystal size not changed. SNM-1 glass ceramics samples show a predominant red up-conversion emission under near infrared excitation at 980nm, while a predominant green emission is observed in the SNM-3 samples. In this paper, it was indicated that it changed the effect of glass network modifier MgO in the glass structure. The possible mechanism responsible for the color variation of UC in Er3+/Yb3+ co-doped was discussed.

Novel Electrospun Dual-Layered Composite Nanofibrous Membrane Endowed with Electricity–Magnetism Bifunctionality at One Layer and Photoluminescence at the Other Layer

Dual-layered composite nanofibrous membrane equipped with electrical conduction, magnetism and photoluminescence trifunctionality is constructed via electrospinning. The composite membrane consists of a polyaniline (PANI)/Fe3O4 nanoparticles (NPs)/polyacrylonitrile (PAN) tuned electrical-magnetic bifunctional nanofibrous layer at one side and a Eu(TTA)3(TPPO)2/polyvinylpyrrolidone (PVP) photoluminescent nanofibrous layer at the other side, and the two layers are tightly combined face-to-face together into the novel dual-layered composite membrane with trifunctionality. The electric conductivity and magnetism of electrical-magnetic bifunctionality can be respectively tunable via modulating the respective PANI and Fe3O4 NPs contents, and the highest electric conductivity approaches the order of 1 × 10-2 S cm-1. Predominant red emission at 615 nm can be obviously observed in the photoluminescent layer under 366 nm excitation. Moreover, the luminescent intensity of photoluminescent layer is almost unaffected by the electrical-magnetic bifunctional layer because of the fact that the photoluminescent materials have been successfully isolated from dark-colored PANI and Fe3O4 NPs. The novel dual-layered composite nanofibrous membrane with trifunctionality has potentials in many fields. Furthermore, the design philosophy and fabrication method for the dual-layered multifunctional membrane provide a new and facile strategy toward other membranes with multifunctionality.

Peptide nanotube aligning side chains onto one side.

A novel pseudo cyclic penta-β-peptide composed of a β-naphthylalanine, two β-alanines, and a sequence of ethylenediamine-succinic acid (CP5ES) is synthesized and investigated on peptide nanotube (PNT) formation. When the PNT is formed with the maximum number of intermolecular hydrogen bonds between the cyclic peptides, the sequence enables the alignment of the side chains, naphthyl groups, on one side of the PNT. Microscopic and spectroscopic observations of CP5ES crystals reveal that CP5ES forms rod- or needle-shaped molecular assemblies showing exciton coupling of the Cotton effect and predominant monomer emission, which are different from a reference cyclic tri-β-peptide composed of a β-naphthylalanine and two β-alanines. Insertion of a sequence of ethylenediamine-succinic acid into β-amino acids in the cyclic skeleton is therefore suggested to be effective to make the side chains aligning on one side of the PNT. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.