Intercrossed Carbon Nanorings with Pure Surface States as Low‐Cost and Environment‐Friendly Phosphors for White‐Light‐Emitting Diodes

Li, Xiaoming; Li, Yanli; Song, Xiufeng; Wang, Hao; Gu, Haoshuang; Zeng, Haibo

doi:10.1002/anie.201406836

Cited by 245 publications

(125 citation statements)

References 36 publications

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“…[50] Figure S1 (Supporting Information) shows S-AIMs with irregular shapes and randomly distributed particle size at 0.5-50 µm, which are www.advmattechnol.de further confirmed by the scanning electron microscopy (SEM) images in Figure 3b. [23,27,51] S-AIMs can effectively solve this issue since the PQD mean size of 22 nm ( Figure S4, Supporting Information) is comparable to the S-AIM mean pore size of 20 nm ( Figure S5, Supporting Information). These random pore structures and the rough surface lead to a combined effect, preventing the ambient moisture from penetrating into the S-AIMs, and as will be discussed in the following, serve for protecting the PQDs.…”

Section: Resultsmentioning

confidence: 99%

Highly Efficient and Water‐Stable Lead Halide Perovskite Quantum Dots Using Superhydrophobic Aerogel Inorganic Matrix for White Light‐Emitting Diodes

Song

et al. 2020

Adv Materials Technologies

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hence have drawn a lot of attention as down-conversion materials for white lightemitting diodes (WLEDs). [7][8][9][10] For practical applications, the cost-effectiveness, the optical performance, and the stability of PQDs should be further improved. [4] Particularly, PQDs suffer from low chemical and optical stabilities, resulting in their fast degradation under exposure to moisture, heat, and light irradiance. [11,12] Accordingly, PQDs exhibit much lower stability than conventional rare-earth-based phosphor materials. [13,14] Current research efforts therefore aim at enhancing the stability of PQDs by covering them in inorganic materials, including CdS, [15] zeolite, [16,17] glass, [18,19] CaF 2 , [20] Al 2 O 3 , [21][22][23] SiO 2 , [24][25][26][27][28][29] and TiO 2 . [30] Generally, the protective shells of PQDs are prepared using these inorganic materials by in situ synthesis. While protected PQDs with high chemical, thermal, and irradiation stabilities have been obtained, [28] the water stability of PQDs prepared with these inorganic shells still indicate a lot of room for improvement. For instance, the PL intensity of CaF 2 shell-integrated green PQDs reduces to <50% after a water-resistance test of ≈40 h. [20] Consequently, and until now, PQDs with high water stability are achieved by embedding them in enclosed organic polymer and glass matrices. [18,19,[31][32][33][34][35][36][37][38][39] The hydrophobic surface and dense polymer chains of the matrix can effectively protect the PQDs from the external environment, considerably enhancing their At present, most of lead halide perovskite quantum dots (PQDs) embedded in an enclosed organic polymer or glass matrix can achieve high water stability, yet this limits their subsequent integration with light-emitting diodes (LEDs) and other functional materials. Herein, a postadsorption process using superhydrophobic aerogel inorganic matrix (S-AIM) with open structures is presented to enhance water stability of PQDs and compose newfunctions to them such as magnetism. The CsPbBr 3 PQDs integrated with the S-AIM (AeroPQDs) exhibit a high relative photoluminescence quantum yield (PLQY, 75.6%) of 90.9% compared to pristine PQDs (PLQY, 83.2%). They preserve their initial PL intensity after 11 days of soaking in water and achieve a high relative PLQY stability (50.5%) after soaking for 3.5 months. The hydrophobic (rough) surface of the matrix, its pores with a well-matched mean diameter that promotes the homogeneous integration of PQDs and hinders the penetration of water as well as the oleophylic functional groups covering the surface of these pores are the three factors responsible for the high water stability. Finally, AeroPQDs are easily integrated with other functional nanomaterials, such as Fe 3 O 4 nanoparticles for magnetic manipulation, due to their open structure.

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Section: Resultsmentioning

confidence: 99%

Highly Efficient and Water‐Stable Lead Halide Perovskite Quantum Dots Using Superhydrophobic Aerogel Inorganic Matrix for White Light‐Emitting Diodes

Song

et al. 2020

Adv Materials Technologies

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“…The resulting combination of yellow light with the residual blue light produces white light as perceived by the human eye12345. These phosphors should efficiently down-convert the blue photon and should maintain good optical performance even at an elevated ambient temperature.…”

mentioning

confidence: 99%

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Anoop

Rani

Lim

et al. 2016

Sci Rep

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The long-term instability of the presently available best commercial phosphor-converted light-emitting diodes (pcLEDs) is the most serious obstacle for the realization of low-cost and energy-saving lighting applications. Emission from pcLEDs starts to degrade after approximately 200 h of operation because of thermal degradation of the phosphors. We propose a new strategy to overcome this thermal degradation problem of phosphors by wrapping the phosphor particles with reduced graphene oxide (rGO). Through the rGO wrapping, we have succeeded in controlling the thermal degradation of phosphors and improving the stability of fabricated pcLEDs. We have fabricated pcLEDs with long-term stability that maintain nearly 98% of their initial luminescence emission intensity even after 800 h of continuous operation at 85 °C and 85% relative humidity. The pcLEDs fabricated using SrBaSi2O2N2:Eu2+ phosphor particles wrapped with reduced graphene oxide are thermally stable because of enhanced heat dissipation that prevents the ionization of Eu2+ to Eu3+. We believe that this technique can be applied to other rare-earth doped phosphors for the realization of highly efficient and stable white LEDs.

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“…Previous studies have reported on several types of carbon nanorings and are shown in Table 1 . The N‐CNRs synthesized by our method have advantages including a rapid reaction time, flexible reaction atmospheric conditions, and low reaction temperature for production when compared to previous studies . The comparison details are summarized in Table .…”

Section: Comparison Between Three Types Of Previously Studied Carbon mentioning

confidence: 99%

Synthesis of Highly Fluorescent Yellow‐Green N‐Doped Carbon Nanorings for pH Variation Detection and Bioimaging

Zhong

et al. 2018

Part & Part Syst Charact

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A facile and direct chemical route is developed to produce intercrossed N‐doped graphene carbon nanorings (N‐CNRs) with a high yellow‐green photoluminescence emission in both solid and aqueous states. The N‐CNRs are directly synthesized at an elevated temperature in an inert atmosphere without additional pressure using urea and sodium citrate as raw materials. N‐CNRs have a photoluminescence change phenomenon from green to blue when the pH is altered from a neutral to a base value. The luminescence mechanism is analyzed under absorbance and lifetime decay, X‐ray photoelectron spectra, and X‐ray absorption near edge structure spectroscopy. Results indicate how the optical properties are tuned. The fluorescence bioimaging of zebrafish using N‐CNRs as the probe is also studied in terms of zebrafish husbandry, embryo harvesting, and the introduction of N‐CNRs into embryos and juveniles by soaking and microinjection. The prepared N‐CNRs serve as a promising fluorescent probe for pH variation analysis, and bioimaging. The N‐CNTs show potential for use in air purification applications.

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Intercrossed Carbon Nanorings with Pure Surface States as Low‐Cost and Environment‐Friendly Phosphors for White‐Light‐Emitting Diodes

Cited by 245 publications

References 36 publications

Highly Efficient and Water‐Stable Lead Halide Perovskite Quantum Dots Using Superhydrophobic Aerogel Inorganic Matrix for White Light‐Emitting Diodes

Highly Efficient and Water‐Stable Lead Halide Perovskite Quantum Dots Using Superhydrophobic Aerogel Inorganic Matrix for White Light‐Emitting Diodes

Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Synthesis of Highly Fluorescent Yellow‐Green N‐Doped Carbon Nanorings for pH Variation Detection and Bioimaging

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