Highly Enhanced Luminescence Performance of LEDs via Controllable Layer‐Structured 3D Photonic Crystals and Photonic Crystal Beads

Abstract

Controllable layer‐structured 3D photonic crystals (PCs) are prepared using the combination of the Langmuir–Blodgett (LB) technique and layer‐by‐layer stacking method. They are used for research into the influence of the number of the layers on the enhancement of the efficiency of light emission from light‐emitting diodes (LEDs) and quantum dots (QDs). The luminescence properties of blue, green, and white LEDs are improved dramatically while applying such controllable layer‐structured 3D PCs as reflectors and the enhancement efficiencies are shown to increase with PC thickness. In addition, the fluorescence intensity increases 7.8‐fold and 5.4‐fold for red and green QDs, respectively, and the fluorescence intensity can be accurately controlled by using PCs with different layers. In addition, PC beads with yellow and red photonic bandgaps are used to improve the luminescence of a white LED with angle‐independent enhancement. These beads are simply doped into the phosphor without any other treatment. Interestingly, the light intensity of the PC bead based LED is remarkably enhanced. These quantized enhanced effect of light intensity on the thickness of PC layers, along with new generation of PC bead based LED, might offer a strategy for designing high brightness LEDs with energy‐saving performance.

New Encryption Strategy of Photonic Crystals with Bilayer Inverse Heterostructure Guided from Transparency Response

“…Surprisingly, the disadvantages of traditional encryption of photonic crystals, such as permanent deformation, environmental instability, elasticity losing, and slow response, could be avoided by precise design. Multilayer structures have been well developed to enhance the luminescence of quantum dots, fluorescent dyes, and light‐emitting diodes due to the fact of widening the reflection spectra of CPCs. Photonic multilayers formed by the layer‐by‐layer deposition exhibiting optical properties that resemble the superposition of the properties of each individual crystal .…”

Hydrophobic Poly(tert‐butyl acrylate) Photonic Crystals towards Robust Energy‐Saving Performance

“…[7] Thep hotonic band gap (PBG) of PCs can prevent the propagation of light with particular wavelengths,w hich originates from the manipulated movement of photons. [9] In this regard, much important efforts have been expended on poly(St-MMA-AA) PCs films, [10] SiO 2 nanohoneycomb arrays, [11] 3D PS@P(BA-MAA) PCs reflectors, [9] and Rhodamine 6G derivative-infiltrated SiO 2 inverse opal PCs. [9] In this regard, much important efforts have been expended on poly(St-MMA-AA) PCs films, [10] SiO 2 nanohoneycomb arrays, [11] 3D PS@P(BA-MAA) PCs reflectors, [9] and Rhodamine 6G derivative-infiltrated SiO 2 inverse opal PCs.…”

“…[9] In this regard, much important efforts have been expended on poly(St-MMA-AA) PCs films, [10] SiO 2 nanohoneycomb arrays, [11] 3D PS@P(BA-MAA) PCs reflectors, [9] and Rhodamine 6G derivative-infiltrated SiO 2 inverse opal PCs. [11] In our previous work, [9] we reported ac ontrollable layer-structured 3D PS@P(BA-MAA) PCs as ar eflector to improve the PL intensity of CdTeQ Ds in LED devices.T he enhanced efficiencies could be precisely controlled through manipulating the number of layers of PS@P(BA-MAA) PCs in which the PL intensity of CdTeQDs in LED devices was increased 7.8-fold. [11] In our previous work, [9] we reported ac ontrollable layer-structured 3D PS@P(BA-MAA) PCs as ar eflector to improve the PL intensity of CdTeQ Ds in LED devices.T he enhanced efficiencies could be precisely controlled through manipulating the number of layers of PS@P(BA-MAA) PCs in which the PL intensity of CdTeQDs in LED devices was increased 7.8-fold.…”

“…[8] Owing to that, PCs can serve as areflecting substrate to improve the intensity of PL, wherein corresponding PBG is well-matched with the PL wavelength. [9] In this regard, much important efforts have been expended on poly(St-MMA-AA) PCs films, [10] SiO 2 nanohoneycomb arrays, [11] 3D PS@P(BA-MAA) PCs reflectors, [9] and Rhodamine 6G derivative-infiltrated SiO 2 inverse opal PCs. [12] For example,S ongsg roup [10] combined the advantages of poly(St-MMA-AA) PCs film with different quantum dot (QDs) film in QDs-based LED devices.T he corresponding PL intensity of QDs emission on the poly(St-MMA-AA) PCs was enhanced 8-fold compared with the control sample.H ea nd co-workers proposed the periodic SiO 2 nanohoneycomb arrays to enhance the LED light output.…”

“…[12] For example,S ongsg roup [10] combined the advantages of poly(St-MMA-AA) PCs film with different quantum dot (QDs) film in QDs-based LED devices.T he corresponding PL intensity of QDs emission on the poly(St-MMA-AA) PCs was enhanced 8-fold compared with the control sample.H ea nd co-workers proposed the periodic SiO 2 nanohoneycomb arrays to enhance the LED light output. [11] In our previous work, [9] we reported ac ontrollable layer-structured 3D PS@P(BA-MAA) PCs as ar eflector to improve the PL intensity of CdTeQ Ds in LED devices.T he enhanced efficiencies could be precisely controlled through manipulating the number of layers of PS@P(BA-MAA) PCs in which the PL intensity of CdTeQDs in LED devices was increased 7.8-fold. However,t hese conventional PCs materials,i ncluding PMMA, [13] polystyrene (PS), [14] and silica (SiO 2 )m aterials [15] are vulnerable to macroscopically crack at the large areas because of the high glass transition temperature (T g ) and weak interactions between building blocks.Those greatly restrict the PL enhanced efficiency of PC film in energy saving devices.T os olve it, the polyamidoamine (PAMAM) dendrimer grafted onto the surface of P(St-MMA-AA) PCs could achieve crack-free PCs film, which profited from the hydrogen bond interactions of dendrimer loaded P(St-MMA-AA) particles.…”