Luminescence Thermal Stability Research Articles

Stable Polyhedron-Cluster-Based Rigid Fluoride Framework toward Zero-Thermal-Quenching Near-Infrared Emission for Prolonged LED Applications.

Development of highly thermally stable broadband near-infrared (NIR) luminescence materials is crucial for advancing the prolonged stable application of smart NIR light sources. In this study, a zero-thermal-quenching and reversible temperature-dependent broadband NIR-emitting Cs2NaAl3F12:Cr3+ phosphor is demonstrated, benefiting from its stable polyhedron-cluster-building rigid structure. The excellent thermal stability of Cs2NaAl3F12:Cr3+ is rooted in its stable [Al6Na4F45] cluster building unit, which provides a rigid structure with a weak electron-phonon coupling effect and a wide band gap with a huge thermal activated barrier. Such characteristics are well revealed by multiple studies on crystal structure, electronic structure, Huang-Rhys factor S, configuration coordinate model, and Debye temperature. The incorporation of Li or K instead of Na weakens the luminescence thermal stability, directly proving the importance of the stable [Al6Na4F45] cluster for stable Cr3+ substitution and rigid structure construction. Furthermore, Cs2NaAl3F12:Cr3+ presents much superior thermal stability compared to traditional rigid garnet-type fluorides Na3X2Li3F12:Cr3+ (X = Al, Ga, In). A high-power NIR LED is presented, utilizing the high quantum efficiency (∼71%) and extremely thermally stable broadband NIR emission around 750 nm of Cs2NaAl3F12:Cr3+. It realizes clear vein and cartilage imaging in the human hand, demonstrating its potential in medical diagnosis applications. This result provides important insights for designing new-type rigid crystal structures using stable polyhedron clusters as basic units, advancing the development of highly thermally stable NIR-emitting phosphors.

Defect engineering towards anti-temperature quenching luminescence for application in light emitting diodes

Thermal quenching (TQ) that weakens luminescent intensity is crucial for the application value of a phosphor. Here, we report a series of color-tunable phosphors Na2MgAl10O17:xEu2+ (NMA:xEu2+) from green to cyan. For optimized Eu2+ concentration of x = 0.15, its internal and external quantum efficiency can reach up to 86% and 43%, respectively. In addition, it is unexpected that NMA:0.15Eu2+ exhibits anti-temperature quenching (TQ) luminescence even up to 300 °C, which is due to the ability of the defect energy levels to counteract the usual loss of emission by TQ through EPR and TL spectral analysis. Then, a prototype w-LED lamp by using NMA:0.15Eu2+ cyan phosphor, CaAlSiN3:Eu2+ red phosphor, and 380 nm LED chip is fabricated. This work not only reports a new phosphor with high efficiency and good thermal stability of luminescence, but also brings forward a defect engineering approach for enhancing the thermal quenching resistance of a phosphor.

Dual anti-thermal quenching induced by defect levels of the Ba3EuAl2O7.5 phosphor

The thermal quenching effect is a serious challenge for phosphors operating at elevated temperatures. Herein, dual anti-thermal quenching is observed from 298 to 523 K in the defect-rich Ba3EuAl2O7.5 phosphor upon the excitations of 270 and 392 nm. The integrated emission intensity of Eu3+ continuously increases by 145% and 156% and reaches maximums at temperatures of 443 and 483 K under the excitations of 270 and 392 nm, respectively. The defect levels, as demonstrated by the thermoluminescence glow curves, capture the electrons and compensate for the thermal quenching of Eu3+ luminescence. The electron paramagnetic resonance and x-ray diffraction reveal that the defects are associated with oxygen vacancies. This work provides an approach to implement the anti-thermal quenching effect by introducing structural defects. Meanwhile, the outstanding thermal stability of luminescence with the excitations in the deep ultraviolet and ultraviolet regimes makes the phosphor Ba3EuAl2O7.5 a competitive candidate for space solar cells and other optical devices.

Luminescence enhancement of Mn4+‐activated double‐perovskite phosphors for LEDs through a co‐replacement strategy

AbstractPhosphors doped with Mn4+ ions have strong emission in the red and far‐red light regions and are therefore used as red phosphors for indoor plant cultivation light‐emitting diodes (LEDs) and white LEDs (w‐LEDs). This paper introduces La2Mg(Mg1/3Ta2/3)O6: Mn4+ (Mg2La3TaO9: Mn4+) red phosphors prepared by conventional high‐temperature solid‐phase method. The broad excitation band of Mg2La3TaO9: Mn4+ phosphor is effectively excited by ultraviolet and blue light in the range of 250–600 nm, with the emission of 707 nm centered on far‐red light. The phosphor has a high color purity of 99.07% and an internal quantum efficiency of 59.87%. To further enhance the performance of the phosphor, a cation substitution method was adopted in this paper to synthesize La2Mg(Al1/2Ta1/2)O6: Mn4+ phosphor by replacing [1/3Mg2+–2/3Ta5+] in La2Mg(Mg1/3Ta2/3)O6: Mn4+ with [1/2Al3+–1/2Ta5+]. The luminescence intensity and thermal stability of the samples were enhanced. The emission spectrum of the Mg2La3TaO9: Mn4+ samples matched well with the phytochrome PFR (phytochrome that absorbs far‐red light) and is suitable for the preparation of LEDs for indoor plant cultivation. The concentration quenching effect of the samples was investigated, the main mechanism of which is the electric dipole–dipole interaction. Red LEDs and w‐LEDs devices were prepared with the synthesized phosphors that produce light stably at different currents. The w‐LEDs have a correlated color temperature of 5310 K and a color rendering index of 80.1. Therefore, these samples are expected to be used as red components for w‐LEDs.

Deep‐Red Ca3Al2Ge3O12:Eu3+ Garnet Phosphor with Near‐Unity Internal Quantum Efficiency and High Thermal Stability for Plant Growth Application

AbstractTrivalent europium (Eu3+) doped phosphors usually radiate orange or red light owing to distinct transitions from the 5D0 excited level to the ground states of 7F1 and 7F2. However, Eu3+ activated phosphors with a dominant deep‐red emission due to 5D0→7F4 transition are relatively rare. In this work, the synthesis and photoluminescence properties of Ca3Al2Ge3O12:Eu3+ deep‐red phosphor with an intense 5D0→7F4 transition are reported. Irradiating this new garnet phosphor with 394 nm near‐ultraviolet light generates a dominant deep‐red emission band centered at 707 nm. The phosphor has a high internal quantum efficiency of 98.4% and excellent luminescence thermal stability, maintaining 78.8% of the room temperature emission intensity at 150 °C. Based on the unique spectral feature of this new compound, a phosphor‐converted deep‐red LED prototype device is fabricated, producing an output power of 27.3 mW with a photoelectric conversion efficiency of 4.0% at 200 mA. Plant growth experiments are also conducted to demonstrate the obvious positive effects of the fabricated deep‐red LED on plant growth, further indicating that the as‐prepared Ca3Al2Ge3O12:Eu3+ deep‐red phosphor can act as a promising luminescence converter for plant growth LED bulbs.

Enhancing quantum efficiency and thermal stability in Gd2SrAl2O7: Mn4+, Bi3+, Na+ far-red emitting phosphor by energy transfer and cation substitution strategy for indoor plant growth LED lighting

In this work, we synthesized a series of Gd2SrAl2O7: Mn4+/Bi3+/Na+ phosphors by sol-gel method. The experimental results show that there is energy transfer from Bi3+ to Mn4+. By introducing Bi3+ and Na+ ions into the host, emission intensity of the optimal phosphor can be increased to 2.5 times that of Gd2SrAl2O7: Mn4+ and its internal quantum yield is as high as 79.9%. Furthermore, the optimal phosphor also exhibits satisfactory luminescence thermal stability, whose PL intensity at 423 K retained 80.2% of that at room temperature and the activation energy reaches up to 0.45 eV. Mechanism of photoluminescence improvement can be attributed to efficient energy transfer, charge compensation and enhanced crystal rigidity. Packaged LED device exhibits dazzle far red light and its PL spectrum widely overlaps with the absorption band of phytochrome PFR. The performance indexes support the prospective application of the optimal phosphor in plant growth lighting.

Effect of B2O3 on luminescence and scintillation properties of Ce3+-doped gadolinium aluminium–silicate glass

Different B2O3 content was added to Ce3+–doped Gd2O3–Al2O3–SiO2 (xBGAS:1.1Ce3+, x = 0, 5, 10, 15) glasses to improve the photoluminescence (PL) and scintillation properties. The transmittance of 15BGAS:1.1Ce3+ glass is over 80%. The X–ray absorption near edge spectroscopy (XANES) spectra imply that Ce4+ can be effectively reduced to Ce3+ in the glasses by adding Si3N4. The excitation and emission spectra show a blue shift with increase of B2O3 content. The photoluminescence quantum yield (PL QY) increases with the increase of B2O3 content, reached the maximum of 59.55% when x = 15. The PL decay time of the glasses exhibits typical values (44–50 ns) due to 5d→4f transition of Ce3+ ions. The PL thermal activation energy become larger, indicating that xBGAS:1.1Ce3+ glasses have better luminescent thermal stability. The integral X–ray excited luminescence (XEL) intensity of the 15BGAS:1.1Ce3+ glass is 37.38% of Bi4Ge3O12 (BGO) crystal, and the light yield is 1267 ph/MeV with an energy resolution of 23.22% at 662 keV when exposed to γ–rays. With the increase of B2O3 content, the fast component of scintillation decay time gradually becomes shorter and the slow component becomes longer. The thermally stimulated luminescence (TSL) curves were measured to investigate the trap depth and density of defects in xBGAS:1.1Ce3+ glasses.

Protonated organic cations enhance the luminescence performance and thermal stability of fluoride red phosphor K2TiF6:Mn4+

The application of red luminescent phosphors composed of Mn4+-activated fluoride in WLEDs has aroused great interest. However, most of the fluoride phosphors doped with Mn4+ have poor luminescent thermostability. In order to improve their luminescent thermostability, a new type of organic-inorganic hybrid red luminescent phosphor K2TiF6:PIPH22+,Mn4+ (PIPH22+ = protonated piperazine) was synthesized by a simple cation exchange method in this work. Protonated piperazine was incorporated into K2TiF6 lattice, and the strong hydrogen bond between H- and F- enabled the organic group to exist stably in the inorganic lattice. Compared with K2TiF6:Mn4+, the addition of PIPH22+ increases distance between adjacent [TiF6]2- and inhibits the energy migration of Mn4+ ions between [MnF6]2- to reduce nonradiative transitions. Therefore, the hybrid sample K2TiF6:PIPH22+,Mn4+ has higher emission intensity and quantum yield. Under the excitation of 467 nm blue light, K2TiF6:PIPH22+, Mn4+ exhibits sharp red emission near 631 nm, and the luminescence intensity is 2.14 times that of K2TiF6:Mn4+. K2TiF6:PIPH22+,Mn4+ has significant negative thermal quenching and higher luminescence thermostability, which can be attributed to electron-phonon interaction mechanism at high temperature. The prototype WLED prepared with YAG:Ce3+, K2TiF6:PIPH22+,Mn4+ and InGaN blue LED chip can emit warm white light (CCT = 2795 K, CRI = 91.1) under 20 mA current, and the luminescence efficiency was 105.8 Lm/W. The prototype WLED was tested under 20–120 mA current, and the results showed that the changes of CCT and CRI were stable. These results indicate the potential of K2TiF6:PIPH22+,Mn4+ in WLED applications.

Novel eco-friendly dye-polymer composite films for white LEDs: Syntheses, structures and luminescence properties

Natural luminescent dyes exhibit great potential in white light-emitting diodes (LEDs) due to their non-toxicity, low cost, and environmental compatibility. However, traditional natural luminescent dyes show aggregation-caused quenching and thermally unstable luminescence. Therefore, developing novel natural luminescent dye-based composite materials to overcome these limitations is highly desirable for white LEDs. In this work, BBR-PVA composite films are synthesized with different BBR concentrations through a simple dip-coating method. The structures and luminescent properties of BBR-PVA composite films are investigated. Results demonstrate the formation of BBR J-aggregates in the composite, enhancing the luminescence of BBR-PVA composite films. The presence of intermolecular H-bonds between BBR and PVA molecules improves luminescent thermal stability. Moreover, the relative contributions of BBR J-aggregation and H-bonding interactions to the luminescence of the composites are tuned by varying the BBR concentration. The white LED fabricated using a blue chip and the as-synthesized BBR-PVA composite film shows good luminescence performance at 2.7 V and a driving current of 57 mA. The CIE chromaticity coordinates, the correlated color temperature, color rendering index, and luminous efficiency are (0.32, 0.25), 7238 K, 75 and 12 l m/W, respectively.

Structure and luminescence properties of Cu+ doped glasses prepared by ion exchange

Doped Cu+ glass was prepared by ion exchange method. It was found that the accumulation zone of copper ions would be formed on the glass surface during the process of ion exchange, and there was an extreme point of copper ion distribution concentration about 10 µm inside the glass surface after ion exchange. The exchange depth of copper ions in the sample increased with the increase of ion exchange time. At low ion exchange temperatures, the Cu elements exchanged into the vitreous body exists in the form of Cu+ and Cu2+. With the exchange of Cu+ into the glass, the degree of polymerization of the glasses continued to increase. By raising the ion exchange temperature, a large number of spherical Cu2O grains formed on the surface of the sample, continuing to raise the temperature, these spherical grains agglomerated and adhered to form lamellae structure, mainly composed of oxides of Cu2O and CuO. The PL spectra showed that the ion-exchanged glass exhibited broadband blue-green emission light with a central wavelength of 468 nm and half-height width of 154 nm under 290 nm excitation. The luminescence intensity appeared to increase firstly and then decrease with increasing the ion exchange time. Dispersed spherical Cu2O grains were generated on the surface of the sample exchanged at 410 °C for 16 h. Co-composite luminescence of the spherical Cu2O semiconductor and the Cu+ doped in the glass effectively increased the luminescence intensity of the samples. In addition, the samples showed a favorable thermal stability of luminescence.

Efficient ultra-broadband NIR-II emission achieved by multi-site occupancy in Mg3Ga2GeO8: Ni2+ phosphor

It is an important and urgent task to improve the luminous efficiency and emission bandwidth of existing luminescent materials with emission in near infrared (NIR) spectral region (especially for NIR-II spectral region from 1000 to 1700 nm). Herein, we report a novel Ni2+ doped phosphor Mg3Ga2GeO8: 0.8 %Ni2+ which exhibits ultra-broadband emission (from 1100 to 1700 nm, the full width at half maximum (FWHM) is up to 300 nm) with high quantum efficiency (The internal quantum efficiency (36.7 %) and external quantum efficiency (7.3 %) are relatively high in the reported Ni2+ dope NIR-II emitting phosphors). The phosphor presents desirable thermal stability of luminescence (At 373 K, it remains 56.2 % of the initial intensity at room temperature). This work not only provides an advanced NIR-II emitting phosphor which can be effectively pumped by commercial near ultraviolet light emitting diode chips, but also introduces a new strategy (that is to explore a suitable host in which there exists many different crystalline sites for the occupation of activators) for the exploration of efficient ultra-broadband NIR-II emitting phosphors.

Auto-combustion synthesis of Sm3+-doped NaYF4 phosphors: Concentration quenching, optical transition and luminescent properties

A series of NaYF4:Sm3+ phosphors with various Sm3+ concentrations were prepared via an auto-combustion-assisted fluorination method. By the use of X-ray diffraction (XRD), we investigated the phosphors' crystal structure, and pure phase NaYF4:Sm3+ were confirmed. Irregular and agglomerated hexagonal-like particles were observed in FE-SEM images of the phosphors. Moreover, higher magnification TEM images have been collected. Based on fluorescence spectra, the concentration quenching and luminescence thermal stability of NaYF4:Sm3+ phosphors were studied. On the basis of Van Uitert's model, the electric dipole-dipole interaction was proven to be the mechanism for energy transfer between Sm3+ ions. Furthermore, the temperature-dependent fluorescence was investigated in depth, and it was shown that the Arrhenius model-based crossover process can adequately describe the temperature-dependent thermal quenching behavior of 4G5/2 level for Sm3+ in NaYF4 powders. Finally, based on the diffuse-diffraction spectrum and the fluorescence decay curve, the optical transition properties of Sm3+ in the examined NaYF4 phosphors were analyzed in the framework of Judd-Ofelt theory.

Synthesis and characterization of narrow band emitting phosphors for plant growth and display applications

We developed a tunable Mn4+ doped LaAl1−xGaxO3 oxide phosphor with perovskite structure, synthesized by high-temperature solid-state routes to overcome the challenges of developing cost-effective and efficient narrow-band far-red emitting phosphors for the generation of artificial white light for plant growth. The effect of successfully substituting greater ionic radii Ga3+ for smaller ionic radii Al3+ on photophysical properties was explored theoretically and experimentally. Expansion occurs in the host lattice of LaAl1−xGaxO3:0.001Mn4+ perovskite oxide phosphors, causing a change in Stokes shift; as a result, optical characteristics tunes such as blue shifting the emission spectrum from the near-infrared (NIR) to the far-red spectral region, as well as efficient enhancement of luminescence intensity and thermal stability.

Exclusive confinement of Bi3+-activators in the triangular prism enabling efficient and thermally stable green emission in the tridymite-type phosphor CaBaGa4O8:Bi3.

Recently, Bi3+-activated phosphors have been extensively studied for potential applications in phosphor-converted white light-emitting diodes (pc-WLEDs). However, Bi3+ activators usually exhibit low quantum efficiency and poor thermal stability due to the outermost 6s6p-orbitals of Bi3+ being strongly coupled with the host lattice, inhibiting potential applications. Herein, we rationally design a novel phosphor CaBaGa4O8:Bi3+, which adopts a tridymite-type structure and crystallizes in the space group of Imm2. CaBaGa4O8:Bi3+ presents a bright green light emission peaking at 530 nm with a FWHM narrower than 90 nm. Comprehensive structural and spectroscopic analyses unravelled that Bi3+ emitters were site-selectively incorporated into the triangular prism (Ca2+-site) in CaBaGa4O8:Bi3+ since there exist two distinct crystallographic sites that can accommodate the Bi3+ ions. An excellent luminescence thermal stability of 73% of the ambient temperature photoluminescence intensity can be maintained at 423 K for CaBaGa4O8:0.007Bi3+. Impressively, the quantum efficiency (QE) of CaBaGa4O8:0.007Bi3+ was remarkably improved to 47.2% for CaBaGa4O8:0.007Bi3+,0.03Zn2+via incorporating the Zn2+ compensators without sacrificing the luminescence thermal stability. The high thermal stability and QE of CaBaGa4O8:0.007Bi3+,0.03Zn2+ are superior to most of the Bi3+-activated green-emitting oxide phosphors. The perspective applications in pc-WLEDs for CaBaGa4O8:0.007Bi3+,0.03Zn2+ were also studied by fabricating LED devices.

Optical enhancement of highly efficient organic-inorganic oxyfluoride red phosphors via the cation co-doping strategy.

Herein, a new organic cationic matrix [N(CH3)4]3MoO3F3 suitable for Mn4+ doping was constructed. Due to the large steric hindrance of N[CH3]4+ (TMA), charge compensation defects can be effectively prevented in the heterovalent Mn4+-doping process, and a high IQE (91.05%) was obtained. Through the cation co-doping strategy, Mg2+/Zn2+/Li+ cations were introduced into the Mo6+ cationic site, which improved the crystallinity of the matrix and reduced energy losses, so as to improve luminescence intensity, QE, thermal stability, water stability and other spectral properties. Meanwhile, [N(CH3)4]2TiF6:Mn4+ phosphors with the same TMA organic cation and equivalent Mn4+ doping were synthesized for comparison, and the effects of the Mg2+ cation co-doping strategy on the spectral properties of phosphors with different matrix types (fluoride/oxyfluoride) and substitution types (equivalent/non-equivalent) were analyzed. These findings provide the basis for the preparation of new luminescent materials. Furthermore, according to the optical properties exhibited by these phosphors, they are packaged into WLED devices with excellent photoelectric properties, which are suitable for indoor lighting and display fields.

A broadband near-infrared Cr3+-doped phosphor applied to near-infrared light-emitting diodes: enhanced luminescence and thermal stability by annealing.

Cr3+-activated phosphors with high quantum efficiency show excellent promise in the field of near-infrared (NIR) phosphor converted light-emitting diodes (pc-LEDs). Here, we design an annealing program for Cr3+-doped phosphors containing variable valence elements that cannot be prepared in a reducing atmosphere to enhance their luminescence efficiency and thermal stability. A novel phosphor, Li2Mg3SnO6:Cr3+, developed by this annealing design, containing variable valence element Sn, exhibits higher quantum efficiency and better thermal stability than the one prepared by the conventional solid-state reaction. The Li2Mg3SnO6:0.03Cr3+ sample exhibits broadband NIR emission with a full width at half-maximum (FWHM) of 201 nm. After annealing, the internal quantum efficiency (IQE) and external quantum efficiency (EQE) of the Li2Mg3SnO6:0.03Cr3+ sample are enhanced from 48.5% to 84.7% and from 22.7% to 32.6%, respectively, and the thermal quenching temperature at which the luminescence intensity of the phosphor reduces to half of its initial value is promoted from ∼400 K to ∼425 K. The luminescence intensity of the optimized Li2Mg3SnO6:0.03Cr3+ sample at 425 K (∼152 °C) remains 49.2% of its initial intensity at 300 K. A NIR pc-LED is fabricated by combining the optimized Li2Mg3SnO6:0.03Cr3+ sample with a blue LED (455 nm blue chip), and the NIR radiant fluxes of 3.676 mW (at 10 mA) and 29.21 mW (at 100 mA), as well as a maximum NIR photoelectric efficiency of 14.2%, are obtained. The results show that this novel phosphor has great application potential in NIR pc-LEDs, and the annealing design exhibits huge potential for improving the optical properties of Cr3+-activated phosphors.

Near-infrared luminescence and high thermal stability of Rb2NaScF6:Cr3+ phosphor for spectroscopy applications

A comprehensive investigation of a chromium-doped near-infrared fluoride phosphor with desired anti-thermal quenching behavior.

Influence of framework disordering on the luminescence performance of Cr3+-doped near-infrared phosphors: a case study of A3B6O14-type hosts.

The luminescence efficiency and thermal stability are enduring topics in the realm of phosphors. It is acknowledged that the structural transformation from disorder to order results in increased lattice rigidity, consequently inducing heightened efficiency and enhanced thermal stability. In this case study of the structural evolution of Ca3Ga2Ge4O14:Cr3+, NaCa2GaGe5O14:Cr3+ and Na2CaGe6O14:Cr3+ near-infrared (NIR) phosphors, a significant paradox is revealed: the incongruent relationship between the fluctuating degrees of disorder and the simultaneous improvements in efficiency and thermal stability. By drawing on insights gained from structural analysis, optical investigations, and theoretical calculations, a notable revelation surfaces: the primary factor affecting rigidity and optical performance is not the disordering of the entire lattice, but rather the disordering of the framework itself. The findings elucidate the principle of framework-order engineering for crafting high-performance NIR phosphors.

White light-emitting properties and application testing of Eu3+ co-doped Gd5Si2BO13:Dy3+ phosphors with energy transfer between Dy3+ and Eu3+

LED occupies a broad market due to its many advantages as a fourth-generation solid-state light source. However, single-component white LED generally has the disadvantages of high coloring temperature, low thermal stability, and low luminous efficiency. In order to solve these problems, Gd5Si2BO13:Dy3+,Eu3+ was prepared by a high temperature solid state method using a newer borate matrix based on Gd5Si2BO13. A colour-tunable warm white phosphor was achieved by energy transfer between Dy3+ and Eu3+. The crystal structure, luminescence characteristics, thermal stability of luminescence, fluorescence lifetime and energy transfer mechanism were systematically studied, and the samples obtained had excellent luminescence performance. Its thermal stability of 150 °C luminescence was 83.77%. By adjusting the ratio of Eu3+, its color changes from cool white light to warm white light and finally moves to red light. Its corresponding color temperature can be adjusted to a range of 5475k∼2128 K. The packaging w-LED application test and the application test of colorless fluorescent anti-counterfeiting printing ink were carried out, and both showed excellent performance. This is the first time that Dy3+ and Eu3+ have been studied in Gd5Si2BO13, further understanding the newer substrate Gd5Si2BO13, and promoting the application of single-component warm white LED. Therefore, Gd5Si2BO13:Dy3+,Eu3+ have good market application prospects.

Tunable and Thermally Stable Luminescence from Polycyclic Aromatic Hydrocarbons Confined in a Zeolitic Imidazolate Framework

AbstractMetal–organic frameworks (MOFs) can provide a variety of nanocompartments for the confinement of guest molecules. Furthermore, the emissions of fluorescent molecules can be tuned by confinement. In this study, a solvent‐free “bottle‐around‐ship” method is used to encapsulate perylene and 9,10‐dimethylanthracene, two polycyclic aromatic hydrocarbons, in the MOF ZIF‐8. Luminescence color tuning is achieved, including white‐light emission, when controlling the loading of only a single type of guest. Photophysical analysis suggests that the variations in luminescence result from various guest arrangements in the nanocompartments, as well as host–guest interactions. Because of the tight confinement of the guests, this host–guest system displays excellent luminescence thermal stability.