Maximum Luminescence Research Articles

Synthesis Optimization of BaGdF5:x%Tb3+ Nanophosphors for Tunable Particle Size

X-ray photodynamic therapy (XPDT) is aimed at the treatment of deep-located malignant tumors thanks to the high penetration depth of X-rays. In XPDT therapy, it is necessary to use materials that effectively absorb X-rays and convert them into visible radiation-nanophosphors. Rare-earth elements, fluorides, in particular, doped BaGdF5, are known to serve as efficient nanophosphor. On the other hand, the particle size of nanophosphors has a crucial impact on biodistribution, cell uptake, and cytotoxicity. In this work, we investigated various Tb:Gd ratios in the range from 0.1 to 0.5 and optimized the terbium content to achieve the maximum luminescence under X-ray excitation. The effect of temperature, composition of the ethylene glycol/water solvent, and the synthesis technique (solvothermal and microwave) on the size of the nanophosphors was explored. It was found that the synthesis techniques and the solvent composition had the greatest influence on the averaged particle size. By varying these two parameters, it is possible to tune the size of the nanophosphor particles, which make them suitable for biomedical applications.

Broadband infrared emission of Pr3+-doped BiLa2O4.5 phosphor for optical amplifier applications

Today, the development of broadband optical amplifiers for optical communication applications continues to motivate research into rare earth ion (RE)-activated near-infrared (NIR) emissive materials. Pr3+-doped BiLa2O4.5 phosphors were prepared via the facile solid-state reaction. The phase formation, structural characteristics, and broadband NIR emission of Pr3+ ions are presented. Unlike commonly reported materials activated by Pr3+ ions, 1320 nm luminescence, that usually applied as an amplifier technology in O-band optical communication, has not been detected in BiLa2-2xPr2xO4.5 (x = 0.005–0.05). However, BiLa2-2xPr2xO4.5 shows a broad 1D2→1G4 emission (1400 nm–1550 nm) extending over the E−, S-, and C- bands in optical communication, and its full-width at half-maximum (FWHM) can reach 143 nm at room temperature. Pr3+-doped BiLa2O4.5 is expected to serve as a potential candidate for amplifier materials in E− and S-band communication system technologies. The quenching of the 1320 nm luminescence in BiLa2-2xPr2xO4.5 was discussed via the energy gap based on the high-energy phonons of the host. The maximum doping concentration to achieve maximum near-infrared luminescence (1400 nm–1550 nm band) in BiLa2-2xPr2xO4.5 is x = 0.03. The concentration quenching and luminescence mechanism are discussed via cross-relaxation.

Study of phosphor Ba2Si3O8:Eu2+ to produce WLED devices with support from ZnCdSe/ZnSe quantum dot

We created the blue-green Ba2Si3O8:Eu2+ (or BaE) phosphor treated with Eu2+ using the standard solid-state method with the concentration of Eu as well as heating temperature properly adjusted for the maximum luminescence efficacy. It is possible to excite the said phosphor using near-UV (n-UV) wavelengths and to display its wide emission band, which is the 5d => 4f shift for Eu2+, caused by the combination of the Eu activator and the nearby host. We integrated the said phosphor with the n-UV LED to create the pc-LED (short for diodes based on conversion phosphor). For the task of creating the WLED device that yields significant color rendering index, we combined the orange ZnCdSe/ZnSe quantum dot with a distinctive sheet structure for the pc-LED made with phosphor BaE. This research demonstrates the electroluminescence features of the said elements.

Deep-Blue Electroluminescence from Phosphine-Stabilized Au3 Triangles and Au3 Ag Pyramids.

The optoelectronic applications of clusters emerged rapidly. Cluster light-emitting diodes (CLED) as representative hold promise as a new generation of displays and lightings. However, as one of the main challenges in electroluminescence (EL) field, until present, no deep-blue CLEDs were reported, due to the strict requirements on excited-state characteristics of clusters. Herein, two phosphine-stabilized Au3 triangle and Au3 Ag pyramid named [O(Audppy)3 ]BF4 and [O(Audppy)3 Ag](BF4 )2 were chosen to demonstrate efficient deep-blue CLEDs. The ligand-incorporated charge transfer transitions of the clusters contribute to both singlet and triplet excited states of the clusters, giving rise to phosphorescence at 460 nm and EL emissions at 436 nm. Based on device engineering, the maximum luminescence beyond 8000 nits and the chromatic coordinates with y <0.1 in deep-blue region verify the competence of CLEDs for high-resolution displays.

Deep‐Blue Electroluminescence from Phosphine‐Stabilized Au3 Triangles and Au3Ag Pyramids

AbstractThe optoelectronic applications of clusters emerged rapidly. Cluster light‐emitting diodes (CLED) as representative hold promise as a new generation of displays and lightings. However, as one of the main challenges in electroluminescence (EL) field, until present, no deep‐blue CLEDs were reported, due to the strict requirements on excited‐state characteristics of clusters. Herein, two phosphine‐stabilized Au3 triangle and Au3Ag pyramid named [O(Audppy)3]BF4 and [O(Audppy)3Ag](BF4)2 were chosen to demonstrate efficient deep‐blue CLEDs. The ligand‐incorporated charge transfer transitions of the clusters contribute to both singlet and triplet excited states of the clusters, giving rise to phosphorescence at 460 nm and EL emissions at 436 nm. Based on device engineering, the maximum luminescence beyond 8000 nits and the chromatic coordinates with y &lt;0.1 in deep‐blue region verify the competence of CLEDs for high‐resolution displays.

White light luminescence in Dy/Tm co-doped yttria stabilized zirconia single crystals

A series of high quality Dy2O3 and Tm2O3 co-doped yttria stabilized zirconia (YSZ) single crystals was synthesized. These crystals have a single cubic structure, and exhibit the characteristic of Dy3+ (blue and yellow emissions) and Tm3+ (blue emission) under excitation with NUV light. Importantly, the hue can be varied between blue and white by modifying the Tm3+/Dy3+ ratio. The photoluminescence and decay curves are consistent with the existence of resonance-type energy transfer from Tm3+ to Dy3+ ions via an electric multipole interaction mechanism. Maximum luminescence intensity is observed in YSZ doped with 0.50 mol% Tm2O3 and 0.75 mol% Dy2O3, and this sample has CIE coordinates (x = 0.33, y = 0.33) in accordance with those for white chromaticity. Thus, the outstanding luminescence properties of these single crystals suggest potential applications in white light emission devices.

Synthesis, crystal structure, photoluminescence of Ba3Y2(BO3)4:Er3+ and thermal expansion of Ba3Y2(BO3)4

The Ba3Y2–xErx(BO3)4 (х = 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) phosphors were obtained by crystallization from a melt. The Ba3Y2(BO3)4 crystal structure was refined from single crystal X-ray diffraction data to R = 0.037. Its anisotropic atomic displacement parameters for all atoms were refined for the first time. The borate crystallizes in the orthorhombic crystal system, space group Pnma with unit cell parameters a = 7.673(1), b = 16.44(1), c = 8.977(2) Å, V = 1132.3(3) Å3, Z = 4. These phosphors are isotypical to those of the A3M2(BO3)4 (A = Ca, Sr, Ba, M = Ln, Y, Bi) family. The crystal structure contains the isolated BO3 triangles, two general and a special one independent crystallographic sites for large cations, which are disordered over sites. Thermal behavior of Ba3Y2(BO3)4 was investigated by high-temperature X-ray powder diffraction and thermal expansion coefficients are calculated in a wide temperature range. An inflections of temperature dependencies of the unit cell parameters is observed in a range 600–740 °C. Luminescence spectra, excitation and kinetic curves of the Ba3Y2(BO3)4:Er3+ series are reported. A maximum luminescence intensity is observed for the x = 0.1 sample. According to vibrational spectroscopy data no structural changes upon activation of the Ba3Y2(BO3)4 matrix with the Er ions are observed.

Benzothiadiazole‐Based Green Hybridized Local and Charge‐Transfer (HLCT) Fluorophores as Solution‐Processed Non‐Doped Emitters for Simple Structured Electroluminescent Devices

AbstractHerein, two new solution‐processable HLCT fluorophores (CBzF and CBzFC) based on benzothiadiazole (Bz) derivatives were designed and synthesized (HLCT=hybridized local and charge transfer). Their optical and photophysical properties were experimentally and theoretically studied and verified by the solvatochromic effect and density functional theory calculations. The two molecules demonstrate high solubility, HLCT features, and an intense green fluorescence with solid‐state photoluminescence quantum yields of 63–72 %. Both fluorophores are effectively applied as non‐doped emitters for solution‐processed double‐layered OLEDs, which produce intense green emission colors with low turn‐on voltages (3.0–3.2 V). Specifically, the CBzFC‐based solution‐processed device achieves a high maximum luminescence (24400 cd m−2), high maximum efficiencies (EQEmax=5.59 %, CEmax=12.24 cd A−1, and PEmax=10.54 lm W−1), and decent efficiency low‐off.

Enhancement of single upconversion nanoparticle imaging by topologically segregated core-shell structure with inward energy migration

Manipulating topological arrangement is a powerful tool for tuning energy migration in natural photosynthetic proteins and artificial polymers. Here, we report an inorganic optical nanosystem composed of NaErF4 and NaYbF4, in which topological arrangement enhanced upconversion luminescence. Three architectures are designed for considerations pertaining to energy migration and energy transfer within nanoparticles: outside-in, inside-out, and local energy transfer. The outside-in architecture produces the maximum upconversion luminescence, around 6-times brighter than that of the inside-out at the single-particle level. Monte Carlo simulation suggests a topology-dependent energy migration favoring the upconversion luminescence of outside-in structure. The optimized outside-in structure shows more than an order of magnitude enhancement of upconversion brightness compared to the conventional core-shell structure at the single-particle level and is used for long-term single-particle tracking in living cells. Our findings enable rational nanoprobe engineering for single-molecule imaging and also reveal counter-intuitive relationships between upconversion nanoparticle structure and optical properties.

Inter-band and mid-gap luminescence in CH3NH3PbBr3 single crystal

Photoluminescence is informative to other optoelectronic processes that are less directly accessible in metal halide perovskites. In this study, we conducted optical studies on CH3NH3PbBr3 single crystals with robust cubic lattices and atomically flat surfaces. Inter-band luminescence peaking aside from the absorption cutoff was observed, and its shifts toward shorter wavelength upon cooling. Cooling the crystal below 150 K leads to the occurrence of mid-gap luminescence partly at the expense of the inter-band luminescence, which indicates bulk photoluminescence quenching by trap-mediated electronic trapping and subsequent mid-gap radiation following electronic de-trapping. Time-resolved photoluminescence probed at the mid-gap luminescence maxima shows two-stage mono-exponential traces, directly corroborating the trapping and de-trapping processes. In the presence of mid-gap luminescence at low temperatures, time-resolved inter-band luminescence demonstrates triplet decaying pathways, in sharp contrast to the doublet decaying pathways at higher temperatures in the absence of mid-gap luminescence. Time- and temperature-resolved inter-band photoluminescence gave rise to a characteristic photocarrier lifetimes evolution against temperature in a close analogy to the material's dielectric constant.

Superior External Quantum Efficiency of LEDs via Quasi-2D Perovskite Crystals Implanted with Phenethylammonium Acetate.

The multiple quantum well structure of a quasi-two-dimensional (quasi-2D) perovskite leads to nonradiative Auger recombination (AR). This is due to high local carrier density in recombination centers, although the radiative recombination is improved by efficient energy transfer. In this study, we suppress the AR by introducing phenethylammonium acetate (PEAAc) into the quasi-2D PEA2Csn-1PbnBr3n+1 perovskite. The recombination centers of n ≥ 4 phases can be promoted because the COO- preferentially coordinates with Pb2+, inhibiting the fast formation of n = 1, 2, 3 phases with phenethylammonium anion (PEA+). Thus, the AR is suppressed due to the lower density of local charge carriers. To balance the AR suppression and decreasing binding energy in promoting the n ≥ 4 phases, the PEAAc:PEABr molar ratios are adjusted. At the optimal molar ratio, perovskite light-emitting diodes (PeLEDs) with a maximum luminescence of ∼29942 cd m-2 and a maximum external quantum efficiency of ∼20.2% are achieved. These results confirm the most efficient PeLEDs based on PEA2Csn-1PbnBr3n+1 without passivation. Moreover, the efficiency roll off is significantly mitigated with a high threshold of over 3.51 mA/cm2. This study develops high-efficiency PeLEDs with a low efficiency rolloff.

Luminescent push-pull triphenylamine-based molecules end-capped with various electron-withdrawing groups: Synthesis and properties

Organic luminescent materials are widely used in various electronic and optoelectronic devices upon growing demands of science and technology. Enhancement of spectral-luminescence characteristics for such materials and in depth understanding of “structure-property” relationships remain challenging tasks. Herein, we report on synthesis and comprehensive investigation of the series of novel luminescent push-pull molecules with triphenylamine unit as an electron donor block and thiophene as a π-spacer, which end-capped with various types of electron-withdrawing groups (EWGs), which are commonly used for the molecular design of various functional materials in organic electronics. The results allowed us to evaluate the impact of EWG type used on the target materials characteristics. Phenyl-substituted EWGs were found to be more suitable for the design of highly thermally and electrochemically stable materials with relatively high melting temperatures and melting enthalpies. Depending on the EWG nature luminescence maxima of the luminophores demonstrated significant variability, e.g. from 509 nm to 750 nm, while the photoluminescence quantum yield (PLQY) values laid in the range of 1–89%. All luminophores showed good compatibility with a polystyrene (PS) matrix, in which PLQYs were generally higher (up to 25-fold enhancement) compared to the corresponding solutions or polycrystalline films. The changes of spectral characteristics observed for these luminophores were well described using basic relations of the semi-empirical theory of solvatochromism. Based on lifetime of excited states measurements, it was shown that the excited state non-radiative deactivation constants values the major contributors to PLQY values in THF solutions, while increase of the PLQY values in PS films can be associated with decrease of the probability of non-radiative deactivation of the excited states.

Photo- and electro-luminescent properties of difluoroboron complexes based on the carbazole-functionalized 2-(benzo[d]thiazol-2-yl)phenol ligands

This article describes the synthesis and luminescent properties of two carbazole-functionalized 2-(benzo[d]thiazol-2-yl)phenol ligands (BTZ-Cz-OH and BTZ-DCz-OH) and their difluoroboron complexes (BTZ-Cz-BF and BTZ-DCz-BF) as the emitting materials. All of the emitting materials were characterized by NMR (1H and 13C) spectroscopy, high-resolution mass spectroscopy and elemental analysis, and they possess good thermal and electrochemical stabilities. The ligands exhibit green emission in solution and solid thin films due to the characteristics of excited-state intramolecular proton-transfer (ESIPT). Upon coordination to the difluoroboron complexes, a significant blue-shift and enhanced emission is observed due to the restricted conformation change. These materials are successfully used as the doped emitters in organic light-emitting diodes (OLEDs), and all the doped devices exhibit strong emission with low turn-on voltages (3.9–4.8 V), and the doped devices based on the difluoroboron complexes exhibit better EL performances than that of the ligands. Especially, the doped device of BTZ-Cz-BF with the dopant concentration of 10 wt% shows the best EL performances with a maximum luminescence of 3940 cd/m2, a maximum current efficiency of 8.26 cd/A and a maximum external quantum efficiency (EQE) of 3.34%.

Yb3+, Er3+: CeF3 crystals: Growth, first-principles simulation, and near-infrared optical properties

Yb3+, Er3+: CeF3 crystals were successfully grown via Bridgman-Stockbarger technique, and their structure and physicochemical properties were characterized and analyzed. The results have shown that the maximum phonon vibrational frequency of the crystals is 391 cm−1. Under 980 nm excitation, Yb3+ ions doping can effectively improve the luminescence intensity at 1550 nm. The maximum luminescence intensity was achieved at the Yb3+ ion concentration of 3 at.%. The energy transfers, concentration quenching mechanisms and the factors affecting the fluorescence decay time were investigated in detail. The band gap structure, density of states and charge distribution of Yb3+, Er3+: CeF3 crystals were studied in depth by first principles simulation. This work proves that Yb3+, Er3+: CeF3 crystals have great potential for the near-infrared laser applications.

Preparation, crystal structure, luminescence and Hirshfeld surface of hydroxynaphthene-based compounds

To explore the new luminescent materials, two compounds based on hydroxynaphthene group have been prepared. Compound 2 was synthesized through the esterification of compound 1 in the acid conditions. They have been characterized by IR, EA and single crystal X-ray diffraction. Single X-ray diffraction reveals that compounds 1 and 2 belong to the P21/n and P21/c, respectively. It is obviously observed that there exist C/OH⋯O and the packing interactions among the aromatic rings. The solid-state fluorescent spectra reveal that the maxima of compounds 1 and 2 are 448 and 415 nm, respectively. The luminescent emission maxima are in accordance with the stacking interactions of compounds. The melting points of both compounds can be found to be 190–192 °C and 78–80 °C, respectively. The Hirshfeld surface analysis further reveals that the close contacts C⋯C are responsible for the luminescent peaks, and the O⋯H/H⋯O close bonds can account for the melting points of both compounds.

Solvent-mediated surface ligand exchange to enhance the performance of quantum-dot light-emitting diodes

Colloidal quantum dots (QDs) with core-shell structure and long-chain organic ligands are widely used as emitting-material layers (EMLs) for quantum-dot light-emitting diodes (QLEDs). However, the poor conductivity of long-chain organic ligands severely affects charge injection into QD-EMLs and charge transport among QDs, usually leading to poor device performance. To address the issue, we partially replaced the original long-chain oleic acid (OA) ligands capping on the QD surface with short-chain 1,2-ethanedithiol (EDT) ligands via solvent-mediated solid-state ligand exchange to fabricate high-performance QLEDs. The effects of solvent (acetonitrile and ethanol)-mediated EDT ligand exchange on the properties of QDs and device performance were comparatively investigated. Our results show that the ligand exchange is more sufficient when using ethanol instead of acetonitrile as the solvent for EDT, which is not only capable of improving charge transport among QDs but also capable of enhancing hole-electron injection balance in QLEDs. As a result, the QLED device based on QDs after EDT (in ethanol) ligand exchange exhibits a maximum luminescence of 190,200 cd/m 2 , a maximum current efficiency of 18.34 cd/A, a maximum power efficiency of 9.60 l m/W and a peak external quantum efficiency of 12.26%, appreciably outperforming those based on pristine QDs and QDs after EDT (in acetonitrile) ligand exchange. After aging, its maximum current efficiency, maximum power efficiency and peak external quantum efficiency can reach up to 35.91 cd/A, 23.30 l m/W and 24.00%, respectively. Our results highlight the importance of surface chemistry control via solvent-mediated ligand exchange to fabricate high-performance QLEDs, and suggest that ethanol may be a more suitable solvent for EDT to fulfill solid-state ligand exchange of core/shell QDs. • Solvent mediated 1,2-ethanedithiol (EDT) ligand exchange is reported to enhance the performance of QLEDs. • The ligand exchange is more sufficient when using ethanol instead of acetonitrile as the solvent for EDT. • Ethanol mediated ligand exchange can improve charge transport among QDs and enhance hole-electron injection balance in QLEDs. • Devices based on EDT/ethanol ligand-exchanged QDs surpass those based on pristine or EDT/acetonitrile ligand-exchanged QDs.

Improvement in white light emission of Dy3+ doped CaMoO4 via Zn2+ co-doping

The research in developing a single ingredient phosphor for white-light emission is progressively increasing. It is well known that the 4F9/2 → 6H13/2 (yellow) and 4F9/2 → 6H15/2 (blue) transitions of Dy3+ ions give near-white light emission. The white light emission of Dy3+ ions can be enhanced via improving the crystallinity of the host phosphor via co-doping of transition metal ions. In this paper, we report a significant improvement in the white light emission of Dy3+ doped CaMoO4 by co-doping Zn2+ ions. The x-ray diffraction pattern confirms the tetragonal phase of pure and doped CaMoO4 phosphor. The peak broadening and a red-shift in the absorption peak are observed by UV–vis absorption analysis of Zn2+/Dy3+ doped CaMoO4. From Photoluminescence studies, we have observed that in Dy3+ doped CaMoO4, the 4% Dy3+ doped CaMoO4 exhibits maximum emission. The Zn2+ ions are co-doped to further increase the luminescence intensity of CaMoO4:4%Dy3+ and the maximum luminescence is obtained for 0.25% Zn2+ concentration. Two intense emission peaks centered at 484 nm and 574 nm related to transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 of Dy3+ ion are observed for Dy3+ doped phosphor. The 4F9/2 → 6H13/2 transition is the forced electric dipole transition which is affected by its chemical environment. After Zn2+ co-doping, the 4F9/2 → 6H13/2 transition is affected due to a change in asymmetricity around the Dy3+ ions. The 0.25% co-doping of Zn2+ gives 34% enhancement in luminescence emission of 4% Dy3+ doped CaMoO4. As a result, the CIE coordinates of chromaticity diagram and the color purity of the 0.25% Zn2+ co-doped CaMoO4:4Dy3+ show improvement in the overall white light emission. We have shown that with Zn2+ co-doping, the non-radiative relaxations are reduced which results in improved white light emission of Dy3+ions.

New pyridylimidazole-based near-infrared iridophosphors: Synthesis, photophysical properties, and electroluminescence application

A pair of highly efficient near-infrared (NIR) phosphorescent iridium(III) complexes (NIR-Ir1 and NIR-Ir2) based on pyridylimidazole derivatives are rationally designed. 1-(Benzo [b]thiophen-2-yl)isoquinoline is selected as the cyclomedtalating ligand for complexes, which determines the near-infrared phosphorescence. 2-(1H-imidazole-2-yl)pyridine and 2-(pyridin-2-yl)-1H-benzo[d]imidazole serve as the ancillary ligands, which aims to finely adjust the photophysical properties of these two NIR iridophosphors. At room temperature, both complexes exhibit intense near-infrared phosphorescence and the emission spectra well overlap with each other (685 nm with 750 nm as the emission shoulder for NIR-Ir1 and NIR-Ir2), high photoluminescence quantum yield (0.10 for NIR-Ir1, 0.13 for NIR-Ir2) in dichloromethane. The pyridylimidazole-type ancillary ligands incorporated into the complexes enable the effective NIR phosphorescence and the robust chemical stability for NIR organic light-emitting diodes (OLEDs). The preliminary results show that the maximum luminescence and external quantum efficiency for the OLEDs based on new NIR complexes with electroluminescence peaked at around 690 nm are 1,464 cd/m2 and 1.48%, respectively.

(Digital Presentation) Wavelength Controllable Multi-Color Firefly Luciferin Analogues

I will show you the multi-color luciferin analogues, and in particular the usefulness of near-infrared(NIR) luciferin analogues.Firefly bioluminescent reaction requires luciferin, luciferase, Mg2+, ATP and O2, and emits light at 560 nm (green-yellow light). As the light emission efficiency of the firefly bioluminescence system is extremely high(ΦBL=41%), this system is attracting widespread attention as a bioimaging tool.We have studied the relationship between structure modification and the firefly luminescence wavelength, where the luciferase of Photinus pyralis (Ppy) was used. As a result, we are able to control the wavelength of the luciferin analogues to some extent. An analog having the thiazoline ring connected directly to p-(dimethylamino)phenyl group exhibited blue shifted luminescence maximum. Furthermore, replacement of the dimethylamino group into a hydroxyl group caused blue shift of luminescence wavelength. On the other hand, Introduction of a double bond between the thiazoline ring and the benzene ring caused large red shift of luminescence wavelength.Based on these structure-activity relationships, we have synthesized a number of luciferin analogs. The shortest emission wavelength of luciferin analogs is 430 nm, and the longest is 760 nm by using Ppy luciferase. Among them, near-infrared(NIR) light is expected to be applied to in vivo imaging because of its high living body permeability.Therefore, Thus, AkaLumine, a luciferin analogue that produces light at 675 nm wavelength, was developed. This compound was shown to yield useful results when applied to the in vivo imaging of mice. We have improved the characteristics of AkaLumine to optimize this compound for use in in vivo imaging, thus obtaining the compounds dubbed TokeOni and seMpai. In this way, bioluminescence imaging technology is undergoing constant innovation, and we continue to develop NIR luciferin analogues that can be used as imaging tools.In this conference, I will present the characteristics of recently developed multi-color luciferin analogues, include NIR luciferin analogues. Figure 1

Drug Ambroxol-based luminescent materials with sulfonate group: Synthesis, crystal structure and Hirshfeld surface analysis

Two new salts with ambroxol moieties, namely, n[HAX]+ nRT– H2O (RT ​= ​MBS (n ​= ​2, 1) and SBS (n ​= ​1, 2)) [AX ​= ​4-((2-amino-3,5-dibromobenzyl)amino) cyclohexan-1-ol, MBS ​= ​p-toluenesulfonic acid, SBS ​= ​sulfosalicylic acid], which were obtained through the mixture of AX and two phenyl sulfonic acid, respectively. The emission peaks located at 526 and 471 ​nm can be observed for compounds 1 and 2 in the solid state at room temperature, respectively. Compared with the AX itself, the red-shifted values can be observed to be 140 and 85 ​nm for compounds 1 and 2, respectively, revealing that the luminescent maxima are proportional to the intermolecular stacking distances. The decay lifetimes of AX, 1 and 2 can be found to be 0.643, 0.671 and 0.589 ns, respectively. Additionally, the quantum yields of 14.7%, 1.2% and 37.1%, respectively. Compounds 1 and 2 were structurally characterized by X–ray single crystal diffraction, EA, UV–Vis and FT-IR spectra. Single crystal X-ray diffraction reveals that there exists an order of packing distances, which is in a good agreement with that of luminescent maxima. The results calculated by Hirshfeld surface show that the close contacts of C⋯H/H⋯C can be responsible for the luminescent behaviors. The O⋯H/H⋯O close contacts can account for the melting points of compounds. Additionally, the thermal properties for compounds 1 and 2 have been discussed in detail.