Color Conversion Research Articles

Highly Enhanced Light Recycling in Quantum Dot Displays by Sidewall Reflectors

AbstractQuantum dot (QD) color conversion‐based displays have emerged as one of the most promising next‐generation devices due to their superior emission properties in terms of color expression. To date, however, existing QD color conversion layer (QD‐CCL) technologies have suffered from low luminance and power efficiency, mainly due to significant light absorption by the bank structure. Here, the color conversion efficiency of QD‐CCL has been significantly enhanced by fabricating a highly reflective metal layer on the side surface of the bank structure. Using a high‐aspect‐ratio silver reflector fabricated through a secondary sputtering lithographic technique involving argon ion bombardment, the fabricated QD‐CCL is combined with a blue organic light‐emitting diode (OLED) serving as a light source. As a result, light recycling from the reflector significantly enhances color conversion efficiency and luminance by up to 4.60‐fold and 4.29‐fold, respectively. Optical simulation reveals that higher pixel resolution provides greater reflection probabilities during extraction. This photomask‐free approach is not only simple but also highly compatible with existing semiconductor fabrication processes, making it a viable commercial alternative for all color‐converting structures that utilize light‐emitting materials with omnidirectional emission characteristics.

Mini-LED Backlight: Advances and Future Perspectives

Miniaturized-light-emitting diode (mini-LED) backlights have emerged as the state-of-the-art technology for liquid crystal display (LCD), facilitating the improvement in a high dynamic range (HDR) and power saving. The local dimming technology divides the backlight into several dimming zones. Employing mini-LEDs, whose size ranges from 100 to 200 μm, as the light sources can enlarge the number of zones in the local dimming backlight, fulfilling the requirement for HDR. However, the halo effect still acts as one of the primary technological bottlenecks for mini-LED backlights. In this review, packaging technology of LEDs, color conversion, and the driving scheme of mini-LED backlights have been discussed. The strategies to reduce optical crosstalk in adjacent areas by various improved optical structures or to suppress the halo effect of LCDs by mini-LED backlights are summarized. The development trends of mini-LED backlights are also discussed.

Colloidal Synthesis of Blue-Emitting Cs3TmCl6 Nanocrystals via Localized Excitonic Recombination for Down-Conversion White Light-Emitting Diodes.

Lead-halide perovskite nanocrystals (NCs) have gained significant attention for their promising applications in lighting and display technologies. However, blue-emitting NCs have struggled to match the high efficiency of their red and green counterparts. Moreover, many reported blue-emitting perovskite NCs contain heavy metal lead (Pb), which poses risks to human health and the environment. In this study, we synthesized rare-earth-based Cs3TmCl6 NCs via the hot injection method, which exhibit a broadband blue emission at 440 nm. Combined experimental and theoretical studies indicate that the broadband emission in Cs3TmCl6 arises from self-trapped excitons due to the excited-state structural distortion of the [TmCl6]3- cluster. Furthermore, the ultrafast dynamics of charge carriers were analyzed using time-resolved photoluminescence and transient absorption measurements. Encouraged by the remarkable thermal, light, and water stabilities of Cs3TmCl6 NCs, as evidenced by experimental and theoretical results, a white light-emitting diode was further designed and fabricated using the Cs3TmCl6 NCs as the color converter. The device exhibits outstanding performance, achieving a long half-lifetime of 336 h and a large color-rendering index of 87.0. Combining eco-friendly features and a facile synthesis method, the rare-earth-based Cs3TmCl6 NCs mark a significant breakthrough as a reliable blue emitter, showcasing their future potential in lighting and display applications.

A Novel Sapphire@PiGF@Sapphire Color Converter with High Luminescence Saturation Threshold for Laser Lighting

AbstractNext‐generation high‐brightness laser lighting confronts a key challenge in preparing static color‐converting materials with remarkable luminescence saturation. Herein, a novel architecture of transmissive Y3Al5O12: Ce3+ (YAG) phosphor‐in‐glass film (PiGF) with double‐sided sapphires, i.e., a sandwich structured sapphire@PiGF@sapphire (S@PiGF@S) composite, is designed and fabricated by a thermocompression sintering technology. This kind of material can tolerate high laser power density (LPD) for the efficient double‐sided thermal channels and the high‐energy laser spot away from the PiGF emitting layer. As a consequence, the optimized S@PiGF@S color converter yields white light with a high luminous flux (LF) of 7602 lm at a record luminescence saturation threshold of 46.47 W·mm−2 benefiting from its low working temperature of merely 284 °C, which is 6.3 times that of traditional PiGF@sapphire color converter (1205 lm@10.89 W·mm−2). These findings verify that the developed S@PiGF@S color converter enables preferably optical‐thermal performances for promising applications in high‐brightness laser lighting.

High Luminescence Saturation Y3Al5O12: Ce3+‐Diamond Composite Color Converter for High‐Brightness Laser‐Driven White Lighting

AbstractPhosphor‐converted laser lighting confronts enormous challenges in the development of color converters with high luminescence saturation owing to the thermal issues from laser irradiation and phosphor conversion. Herein, a high luminescence saturation Y3Al5O12: Ce3+‐diamond (YAG‐diamond) composite color converter by introducing diamond particles in phosphor‐in‐glass film (PiGF) coated on transparent sapphire substrate is proposed for high‐brightness laser‐driven white lighting. By optimizing the diamond content to 6 wt.%, the YAG‐diamond converter shows a thermal conductivity (TC) of 14.7 W·m−1·K−1 and displays higher luminescence intensity at 175 °C (1.15 times that at 25 °C). Under laser excitation, the YAG‐diamond converter achieves a luminous flux (LF) of 1990 lm at the laser power density (LPD) saturation threshold (ST) of 24.82 W·mm−2, which is far better than the PiGF@sapphire converter with a LF of 1364 lm@17.64 W·mm−2. The laser‐driven converter yields stable white laser light with a correlated color temperature (CCT) of 5714 K and a chromaticity coordinate of (0.3278, 0.3372) at the ST of 24.82 W·mm−2. Furthermore, the working temperature of the converter is decreased by 59 °C (26.6%) under LPD of 10.89 W·mm−2. These results indicate that the proposed YAG‐diamond composite converter displays excellent opto‐thermal performances, which may be a promising luminescence material in high‐brightness white laser lighting.

A Wide Color Gamut and Noniridescent Zinc-Anode Asymmetric Electrochromic Device for Self-Sustaining Color-Adaptive Bio-Camouflage System.

Inspired by camouflage-colored organisms, the development of bio-camouflage systems using electrochromic (EC) technology has gained significant interest. However, existing EC systems struggle with achieving a wide color gamut, noniridescent colors, and self-sustainability. Herein, a self-sustainable color-adaptive bio-camouflage system integrating EC and nanogenerator (NG) technologies, enabling environmental color adaptation, and thermal regulation without an external power source is proposed. The system is based on a zinc-anode EC device (ZECD) with an asymmetric structure, incorporating flexible tungsten oxide and vanadium oxide electrodes. During the EC process, tungsten oxide shifts between blue and transparent, allowing near-infrared thermal modulation, while the vanadium oxide transitions from yellow to transparent. This design enables reversible near-infrared modulation and noniridescent color conversion among black, blue, green, yellow, and transparent. For the self-sustainability of the system, an electromagnetic and triboelectric hybrid NG that collects biomechanical energy is developed. In a typical driven cycle, the integrated system transitions colors and achieves significant near-infrared spectral modulation, demonstrating environmental adaptability and thermal regulation. Experiments on human skin and simulated chameleon color changes further confirm the system's effectiveness. This work highlights the potential of integrating EC and NG technologies to advance color-adaptive camouflage systems, opening new an avenue for bio-camouflage design.

High-Performance Electro-optical Dual-Mode Color-Changing and Energy Storage Device Based on Mo-Doped WO3 and TiO2/NiO Thin Films.

Under optical and electrical control, a multifunctional electro-optical dual-control color-changing and energy storage device not only realizes fast color conversion but also achieves good energy storage performance. In this work, Mo-doped WO3 (Mo-WO3) films were prepared by a one-step hydrothermal method, among which the 2 at. % Mo-doped WO3 film has the best electrochromic and energy storage performance. Meanwhile, TiO2/NiO composite films were prepared by the hydrothermal method and electrodeposition method. The TiO2/NiO/N719 photoanode was prepared by the dip-dyeing method on the TiO2/NiO composite film. The results show that the TiO2/NiO-10s/N719 composite film has excellent photoelectric conversion and energy storage properties. Finally, choosing Mo-WO3 as the cathode and the TiO2/NiO/N719 film as the anode, a multifunctional electro-optical dual-control Mo-WO3@TiO2/NiO/N719 color-changing and energy storage device was constructed. Under electrical control, it shows a fast color switching rate (the coloring/bleaching time is 4.1/2.9 s), excellent coloration efficiency (62.1 cm2/C), obviously improved area capacitance (90.4 mF/cm2), and excellent cycle stability. Under optical control, it shows a shortened optical response time (the coloring/bleaching is 70.3/158.9 s), excellent coloration efficiency (58.2 cm2/C), better area capacitance (51.1 mF/cm2), and excellent photoelectric conversion efficiency.

Siloxane-based oligomer ligands of indium phosphide quantum dots for improving dispersion in a siloxane matrix

The ligands of indium phosphide (InP) quantum dots (QDs) were modified with siloxane-based oligomers in a two-step process to improve the dispersion of InP QDs in a siloxane-based matrix. Oleic acid ligands on InP QDs (InP-OA) were exchanged with 6-mercapto-1-hexanol. Then, the hydroxyl functional groups (–OH) of the ligands were induced to react with poly(dimethylsiloxane), diglycidyl ether terminated (PDMS-DGE) by a ring-opening reaction of epoxide. The chemical bonding between the hydroxyl groups and PDMS-DGE was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. The synthesized InP QDs with PDMS-DGE ligands (InP-PDMS-DGE) were blended with acrylate-siloxane polymers to produce color conversion QD films. The photoluminescence (PL) intensity of the QD films with the InP-PDMS-DGE QDs was improved by 2.3 times compared with that of InP-OA QDs. The color conversion efficiency of the QD films was determined using a blue light-emitting diode (LED), and the QD film containing InP-PDMS-DGE QDs demonstrated a conversion efficiency of 21%, compared to a lower efficiency of 17% for a film containing InP-OA QDs. The stability of the InP-PDMS-DGE film was tested at 85°C with a relative humidity (RH) of 85%, demonstrating an improvement of 28% compared to that with an InP-OA film.

Modelling-assisted geometrical optimization of colloidal quantum color convertor based pixels fabricated by dielectrophoretic directed assembly

Hypothesis: Building competitive color conversion pixels for microdisplays made of semiconductor nanocrystals requires reaching a deposition thickness high enough to absorb all the blue light from the backlight unit. In the case of dielectrophoretic directed assembly of such nanocrystals, modeling and simulations may help understand what the intrinsic limitations of the process are, and may be used to propose new assembly routes.Experiments: A theoretical model of dielectrophoretic interactions between polarizable nano-spheres and an electrostatically patterned substrate has been developed. Monte Carlo simulations have been run using this model to rationalize the effects of parameters driving the dielectrophoretic directed assembly and to find optimal deposition conditions for reaching a maximal thickness of nanocrystal pixels. Experiments with CdSe quantum plates and with alumina spheres embedding quantum plates (micro-pearls) have been carried out and compared to the model.Findings: Modeling and simulations reveal that the directed assembly of semiconductor nanocrystals is limited essentially by the small object size, which sets the maximum dielectrophoretic force they can undergo. They indicate that using larger objects should allow reaching unprecedented assembly heights, but will induce lateral extension of the assembly. This trade-off has been illustrated with diagrams in the parameter space and confirmed experimentally with micro-pearls.

Effects of different rootstocks on fruit quality and non-volatile flavor-related compounds of sweet cherry ‘summit’

In practical sweet cherry production, grafting onto rootstocks is a common practice to enhance environmental adaptability. Rootstocks play a crucial role in influencing scion growth and fruit quality by regulating the absorption and utilization of mineral elements. In this study, the influence of five rootstocks with or without root fertilization during the fruit color conversion period on the fruit quality of sweet cherry ‘Summit’ was observed. The physicochemical characteristics, external color characteristics, and total anthocyanin content of ‘Summit’ were significantly affected by both rootstock and fertilization, with an interaction between the two factors. The content of certain sugar components, organic acid components and phenolic acid components in ‘Summit’ were significantly affected by rootstocks and fertilization. ‘Summit’ grafted on Gisela 5 and H22 exhibited higher sugar content, while ‘Summit’ grafted on H11 and H17 exhibited higher organic and phenolic acid content.

Heat dissipation enhancement of PiGF converter with vapor chamber radiator for high-brightness laser lighting

Laser illumination is widely believed to have great development potential in high-brightness lighting and display. In order to realize high-power laser illumination, an efficient heat dissipation method was proposed for phosphor-in-glass film (PiGF) color converter. The heat dissipation of PiGF converter was enhanced by the vapor chamber radiator (VC). The VC-PiGF converter demonstrates great optical-thermal performances due to its excellent heat dissipation capability. The maximum luminous flux of VC-PiGF converter (3699.3 lm) is 38.2 % higher than that of traditional fin-PiGF converter (2677.1 lm). The VC-PiGF converter has higher laser power saturation threshold (maximum 34.51 W) than the fin-PiGF converter (maximum 29.12 W). As the laser power is 24.82 W, the operating temperature of VC-PiGF converter (128 °C) is 41.8 % lower than that of fin-PiGF (220 °C). In addition, the VC-PiGF converter exhibits stable optical performances and a low surface temperature with the continuous excitation of 15.78 W for 60 min. The VC-PiGF converter packaged in a lighting module has an excellent outdoor test result. The efficient heat dissipation method with high reliability has great application prospects in high-brightness laser lighting.

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

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

Zinc-halide/phenylbutyrate co-passivation of CsPbX3 nanocrystals toward efficient and robust luminescence

Cesium lead halide perovskite nanocrystals (IPNCs) exhibit excellent optoelectronic properties but are susceptible to degradation in practical environments due to their ionic surface and unstable ligand capping. Here, we propose a post-synthesis surface passivation strategy for CsPbX3 (X = Br, I) IPNCs by employing combined zinc halide and zinc phenylbutyrate (Zn(PA)2) as surface ligands. ZnBr2 fills surface halide vacancies on IPNCs, resulting in high photoluminescence efficiency, whereas Zn(PA)2 stabilizes IPNCs by substituting surface ammonium ligands. Additionally, the −PA capping endows IPNCs with high solubility in polystyrene (PS), enabling the direct fabrication of highly efficient and uniform IPNCs-PS color conversion films through in situ polymerization of the IPNC-styrene solution. The resulting IPNCs-PS films displayed significantly enhanced stability, retaining excellent PL persistence after 1000 h of photoaging. This novel ligand and modification method presents a promising strategy for improving the efficiency and stability of IPNCs, facilitating their potential applications in display backlight and other optoelectronic applications.

Regulation of nucleation and crystallization for blade-coating large-area CsPbBr3 perovskite light-emitting diodes

Metal halide perovskite light-emitting diodes (PeLEDs) and large-area perovskite color conversion layers for liquid crystal display exhibit great potential in the field of illumination and display. Blade-coating method stands out as a highly suitable technique for fabricating large-scale films, albeit with challenges such as uneven nucleation coverage and non-uniformity crystallization process. In this work, we developed an in-situ characterization measurement system to monitor the perovskite nucleation, and crystallization process. By incorporating formamidine acetate (FAAc) into perovskite precursor solutions, the nucleation rate and nuclei density of perovskite were increased, leading to more uniform nucleation. In addition, we inserted a layer of [2-(9H-carbazol-9-yl)ethyl] phosphonic acid above the poly(9-vinylcarbazole) hole transport layer. This layer acts as an anchor for the perovskite nano-crystal nuclei formed in the precursor, enhancing the steric hindrance of the solute and subsequently slowing down the crystal growth rate, thereby improving crystal quality. Based on these improvements, large-area perovskite nano-polycrystalline films with significantly improved uniformity and enhanced photoluminescence quantum yield were obtained. A small-area PeLED (2 mm × 2 mm) with a maximum external quantum efficiency of 25.91% was realized, marking the highest record of PeLED prepared by blade-coating method to date. An ultra-large-area PeLED (5 cm × 7 cm) was also prepared, which is the largest PeLED prepared by the solution method reported so far.

Study on electro-optical dual-control color-changing and energy-storage device based on Mo-WO3 and Al-TiO2 thin film electrode

Under optical and electrical control, a multifunctional electro-optical dual-control color-changing and energy-storage device not only realizes quick color conversion, but also achieves good storage performance. In this work, Mo doped WO3 (Mo-WO3) films were synthesized through one-step hydrothermal method and N719/Al doped TiO2 (N719/Al-TiO2) films were synthesized by hydrothermal and dip-dyeing method. Eventually, choosing Mo-WO3 as cathode and N719/Al-TiO2 film as anode, a multifunctional electro-optical dual-control Mo-WO3@N719/Al-TiO2 color-changing and energy-storage device was constructed. Under electrical control, the device shows excellent coloration efficiency (73.99 cm2/C), fast color switching rate (coloring/ bleaching time is 3.6 s/1.4 s), obviously improved area capacitance (about 82.6 mF/cm2) and excellent cycle stability. Under optical control, the device also shows shortened response time (coloring/ bleaching is 64.3 s/143.4 s), outstanding coloration efficiency (70.49 cm2/C), better area capacitance (about 58.6 mF/cm2) and excellent photoelectric conversion efficiency (10.56 %).

Efficient and tunable emission of Na5Lu(WO4)4:Tb3+,Eu3+ phosphors for warm white LEDs with high color rendering index

Phosphors with high luminescence efficiency, tunable emission and high color rendering index (CRI) are vital importance for the quality of white light emitting diodes (w-LEDs) in real application. In this work, a new single phase color-tunable Na5Lu(WO4)4:Tb3+,Eu3+ phosphor with outstanding luminescent properties was designed and synthesized. Its crystal structure, electronic structure, and luminescence features were studied in detail. The band gap of the host was calculated to be at about 4.68 eV. The differential charge distribution after Tb, Eu doping through density functional theory simulation theoretically proved the electron redistribution in the W-O bond upon substitution of Tb3+/Eu3+. The energy transfer of Tb3+→Eu3+ enabled tunable emission of luminescent colors from green to orange-red due to the quadrupole-quadrupole interaction. The optimal Na5Lu(WO4)4:60%Tb3+,20%Eu3+ phosphor exhibited excellent photoluminescence quantum yield of 84.19% and good luminescent thermal stability (I423K/298K = 75.90%) with an activation energy of 0.1976 eV. Finally, a white LED device with color coordinates of (0.3371, 0.3636), color rendering index of 89.4 and correlated color temperature of 5334 K was fabricated. These findings demonstrated that Na5Lu(WO4)4:60%Tb3+,20%Eu3+ phosphor could be a potential orange-red-emitting color converter for white LEDs. This work not only assisted in the understanding of experimental observations but also provided a theoretical basis for the rational design of phosphors.

Synergistic effect induces self crystallization of CsPbBr3 quantum dots in Borosilicate glass matrix By LiF

Cesium lead halide perovskite (CsPbX3) quantum dots (QDs) are recognized as viable substitutes for conventional fluorescent powder color converters, which can improve the color gamut and reproducibility of liquid crystal displays (LCDs). Encapsulating QDs in glass can effectively solve the water oxygen stability of QDs, but the glass matrix impedes the nucleation of QDs and the precipitation of QDs requires secondary heating. In our research, we successfully accomplished the self-crystallization of CsPbBr3 QDs facilitated by LiF within a B2O3-SiO2-ZnO borosilicate glass matrix.The results indicate that the self crystallization of CsPbBr3 QDs induced by LiF in borosilicate glass matrix has a synergistic effect. The Li+ ions can break the glass network structure and facilitate ionic migration and transport, while F- ions have good electronegativity due to ion aggregation, and can strongly attract Cs+ and Pb2+ ions with larger atomic radii, thereby promoting the rapid nucleation and growth of CsPbBr3 QDs, ultimately synthesizing QDs with uniform particle size, narrow half peak width, good optical properties, and thermal stability.

Synthesis, Structure and Luminescence Properties of Mn-doped MgAl2O4 Red-Emitting Phosphors with Varying Sintering Temperature.

Oxide matrix red-emitting phosphors are deemed as excellent color converters for white light emitting diodes (WLEDs) and laser diodes (LDs). Manganese-doped MgAl2O4 powder was synthesized by a solid-state reaction method at different sintering temperatures. Microstructure shows that grain size is mainly in the range of 0.2-5μm, and grain agglomeration occurs with increased sintering temperature. XPS analysis indicates that the doped Mn ion exhibits a valence state of + 4 within the MgAl2O4 matrix. The diffraction peak of the phosphors is shifted by the sintering temperature, which affects lattice constant. Upon excitation by 300nm ultraviolet light, the samples emit asymmetric broadband red light within the range of 620-720nm, attributed to Mn4+ ion's transition from 2Eg to 4A2g states. With the increasing temperature, the main emission peak shifts from 677nm to 650nm, ascribed to the change in energy level (2Eg) resulting from the reduction of Al2O3 phase. Crystal field theory confirmed that Mn4+ ions are within a strong crystal field environment created by MgAl2O4 matrix. By affecting particle size and crystallinity, the sintering temperature influences the fluorescence lifetime of the Mn4+ ion. Notably, these red-emitting phosphors exhibits remarkable thermal stability as their emission intensity remains approximately at 58% of initial intensity even at elevated temperature (435K). Consequently, Mn4+: MgAl2O4 red-emitting phosphors with high thermal stability render them promising candidates for WLED applications.

Unraveling the Ultrasonic-Assisted Synthesis of Green-Emitting CsPbBr3@Cs4PbBr6: Reaction Process, Luminescence Property, and Display Application.

The pursuit of stable and highly emissive perovskite materials has garnered increasing attention in optoelectronic applications. Green-emitting CsPbBr3@Cs4PbBr6, as a green-emissive material in the solid-state form, has great potential as a color conversion material for full-color displays. However, it is a challenge to achieve mass preparation under ambient conditions. Meanwhile, the formation mechanism is ambiguous. This study reports a ligand-free and rapid mass synthesis of nanomicrosized CsPbBr3@Cs4PbBr6 solid via an ultrasonic-assisted method. The synthesized CsPbBr3@Cs4PbBr6 solids exhibit uniform morphology, high stability, and solid-state quantum efficiency of approximately 55%. Moreover, the transformation mechanism from Pb-Br complexes in the synthesis process is fully investigated by monitoring the phase and spectral evolution. By employing it as a green emitter, the obtained white light-emitting diode (LED) device shows high performance with a correlation color temperature of 7635 K and a wide color gamut of 123% NTSC. This study offers a low-cost and simple operation mass production method for solid-state perovskite powders with excellent chemical stability. Additionally, it provides new insights into the formation mechanism of highly efficient perovskite materials and promotes their practical applications.

Ultrathin green-emitting LuAG:Ce-Al2O3 composite fine-grained ceramics for high-brightness chip-scale packaging LEDs

To realize green-emitting chip-scale packaging LEDs (CSP-LEDs) with high-brightness, the ultrathin green-emitting phosphor ceramic (PC) with high luminous flux (LF) and luminous efficiency (LE) is urgently explored. LuAG:Ce-Al2O3 fine-grained ceramics (about 150 μm thick) were prepared via vacuum solid-state sintering. Ultrathin LuAG:Ce PC owns LE up to 199.26 lm W−1@50 W as high Ce3+ concentration x = 0.02. Fine-grained composite structure induced by the introduction of Al2O3 results in an increase of LE to 209.95 lm W−1@50 W and an improvement of thermal stability from 91.7 % to 97.2 % at 200℃. It is noteworthy that corresponding optimal packaging CSP-LEDs demonstrates the LF of green lighting up to 978.3 lm@3500 mA. Thus these type of LuAG:Ce-Al2O3 PC is a promising candidate for the color converter of CSP-LEDs.