Thin film fabrication of upconversion lanthanide-doped NaYF4 by a sol-gel method and soft lithographical nanopatterning

Park, Heeyeon; Yoo, Gang Yeol; Kim, Min-Seop; Kim, Kein; Lee, Chiho; Park, Sungnam; Kim, Woong

doi:10.1016/j.jallcom.2017.09.076

Cited by 29 publications

(11 citation statements)

References 45 publications

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“…Then, a small portion of it was scooped with the end of a stainless‐steel pipe (diameter = 5 mm) and blown within a few seconds. The FOG thin films were patterned via a nanoimprinting process . A perfluoropolyether mold was pressed against the FOG film at 100 °C and held for 10 min.…”

Section: Methodsmentioning

confidence: 99%

Fluorescent Organic Glass with Unique Optical and Mechanical Properties

Ku¹,

Joung

Park³

et al. 2018

Adv Funct Materials

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Conventional organic glasses such as molecular and polymeric glasses either lack processability or have ill-defined properties. Here, a novel organic glass is reported having well-defined fluorescent properties and high compatibility with various fabrication processes. The fluorescent organic glass (FOG) is synthesized by simply heating benzyl alcohol with a small amount of aqueous sulfuric acid. Owing to its outstanding optical properties, FOG is placed beyond the domain of conventional organic glasses in the Abbe diagram. Moreover, excellent rheological properties render it amenable to molding, blowing, and nanopatterning processes. Finally, based on extensive characterization, it is proposed that a FOG is composed of a 1,2,3,4-tetraphenyl-1,3-butadiene core and poly(phenylene methylene) branches, which are responsible for molecular fluorescence and polymeric processability, respectively. The demonstration may contribute significantly to the development of organic glasses with unprecedented properties for various applications.

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Section: Methodsmentioning

confidence: 99%

Fluorescent Organic Glass with Unique Optical and Mechanical Properties

Ku¹,

Joung

Park³

et al. 2018

Adv Funct Materials

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“…The proposed structure can be implemented by introducing UC material in the pre-defined air slots of the silicon layer using an atomic layer deposition [30] or growing amorphous silicon layer on the soft lithographically nanopatterned UC slot using the sol-gel method [31].…”

Section: Discussionmentioning

confidence: 99%

Improving Upconversion Efficiency Based on Cross-Patterned Upconversion Material Slot Waveguides on a Silicon Layer

et al. 2019

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Upconversion (UC) materials can be used to harvest near-infrared (NIR) light and convert it into visible light. Although this improves optical device operating spectral range and efficiency, e.g., solar cells, typical UC material conversion efficiency is too low for practical devices. We propose a cross-patterned slot waveguide constructed from UC material embedded in a high index semiconductor layer to improve UC. Since the slot waveguide mode is induced in the low index UC slot, NIR absorption (~970 nm) increased 25-fold compared with film structures. Furthermore, the spontaneous emission enhancement rate at 660 nm increased 9.6-fold compared to the reference film due to resonance excited in the UC slot (Purcell effect). Thus, the proposed UC slot array structure improved UC efficiency 240-fold considering absorption and emission enhancements. This double resonance UC improvement can be applied to practical optical devices.

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“…First, the SiO 2 master had height, diameter, and pitch of ≈1.2 µm, 650 nm and 1.0 µm (or 2.0 µm for triple printing) respectively. The SiO 2 master pattern was prepared via reactive ion etching process by using a layer of polystyrene beads and an underlying Al layer as an etch mask as described in detail in a previous report . A PDMS mold was fabricated by curing Sylgard 184 (Dow Corning) on the patterned SiO 2 master.…”

Section: Methodsmentioning

confidence: 99%

Visualization of UV by Nanopatterned Down‐Shifting Materials Mimicking Human Retinal Cone Cells

Sohn

Park

Yoo

et al. 2019

Adv Funct Materials

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The conversion of invisible ultraviolet (UV) light to visible light by downshifting (DS) materials has a variety of important applications in the fields of optoelectronics and photonics. The ability to control emission colors as a function of the wavelength of incident UV light would significantly advance scientific research and technological applications. A novel strategy for UV visualization is demonstrated that employs nanoimprint lithography combined with a sol-gel process. The principles of trichromacy of human vision are applied; three DS materials sensitive to three different ranges of UV light are nanopatterned to mimic the three types of cone cells in the human retina. Each DS material then emits a distinctive color that can be recognized by each type of cone cells for visualization. The nanopatterned structure significantly intensifies the light emission by Mie scattering and spatially separates the three DS materials, thereby minimizing unwanted optical interference among them. The deliberately designed triple-nanopatterned DS materials exhibit various emission colors ranging from green, to orange, to pink depending on the wavelength of the incident UV light. The current work would contribute to the development of novel strategies for multicolor tunable emission that may lead to innovative applications.

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Thin film fabrication of upconversion lanthanide-doped NaYF4 by a sol-gel method and soft lithographical nanopatterning

Cited by 29 publications

References 45 publications

Fluorescent Organic Glass with Unique Optical and Mechanical Properties

Fluorescent Organic Glass with Unique Optical and Mechanical Properties

Improving Upconversion Efficiency Based on Cross-Patterned Upconversion Material Slot Waveguides on a Silicon Layer

Visualization of UV by Nanopatterned Down‐Shifting Materials Mimicking Human Retinal Cone Cells

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