Photonic crystal and photonic quasicrystal patterned in PDMS surfaces and their effect on LED radiation properties

Suslik, Lubos; Pudiš, Dušan; Goraus, Matej; Nolte, R.J.M.; Kováč, J.; Ďurišová, Jana; Gaso, Peter; Hronec, Pavol; Schaaf, Peter

doi:10.1016/j.apsusc.2016.07.051

Cited by 25 publications

(12 citation statements)

References 23 publications

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“…Like previously reported MSAs [ 19 , 20 , 63 , 65 ], our MSAs also had a novel angle and dimensions to convert a light signal into a visible diffraction pattern that was discernable to naked eyes. In addition, light diffracted to higher orders was desired in an elastomer-based grating [ 66 , 67 ] because, by selecting or blocking these higher orders, the diffracted light can be better modulated and understood [ 66 , 68 , 69 ]. Notably, in all DEL-MSAs, higher-order diffractions (up to 4th) had more than 20% diffraction efficiency (ratio of diffracted intensity to the incident light).…”

Section: Resultsmentioning

confidence: 99%

“…Notably, in all DEL-MSAs, higher-order diffractions (up to 4th) had more than 20% diffraction efficiency (ratio of diffracted intensity to the incident light). More interestingly, some of our MSAs showed a repeated higher intensity at a much higher diffraction order (around 10th order of diffraction) ( Figure 5 C and Figure S1 ), which can efficiently modulate the intensity of longer wavelength signals [ 68 , 69 ]. Furthermore, our DEL-grating can be extended to stimuli-responsive polymers that are highly reactive to external stimuli (example, pH, temperature, or chemical changes) [ 62 , 65 ].…”

Section: Resultsmentioning

confidence: 99%

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Fabrication of Tapered 3D Microstructure Arrays Using Dual-Exposure Lithography (DEL)

2020

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Three-dimensional (3D) microstructure arrays (MSAs) have been widely used in material science and biomedical applications by providing superhydrophobic surfaces, cell-interactive topography, and optical diffraction. These properties are tunable through the engineering of microstructure shapes, dimensions, tapering, and aspect ratios. However, the current fabrication methods are often too complex, expensive, or low-throughput. Here, we present a cost-effective approach to fabricating tapered 3D MSAs using dual-exposure lithography (DEL) and soft lithography. DEL used a strip-patterned film mask to expose the SU-8 photoresist twice. The mask was re-oriented between exposures (90° or 45°), forming an array of dual-exposed areas. The intensity distribution from both exposures overlapped and created an array of 3D overcut micro-pockets in the unexposed regions. These micro-pockets were replicated to DEL-MSAs in polydimethylsiloxane (PDMS). The shape and dimension of DEL-MSAs were tuned by varying the DEL parameters (e.g., exposure energy, inter-exposure wait time, and the photomask re-orientation angle). Further, we characterized various properties of our DEL-MSAs and studied the impact of their shape and dimension. All DEL-MSAs showed optical diffraction capability and increased hydrophobicity compared to plain PDMS surface. The hydrophobicity and diffraction angles were tunable based on the MSA shape and aspect ratio. Among the five MSAs fabricated, the two tallest DEL-MSAs demonstrated superhydrophobicity (contact angles >150°). Further, these tallest structures also demonstrated patterning proteins (with ~6–7 μm resolution), and mammalian cells, through microcontact printing and direct culturing, respectively. Our DEL method is simple, scalable, and cost-effective to fabricate structure-tunable microstructures for anti-wetting, optical-, and bio-applications.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Fabrication of Tapered 3D Microstructure Arrays Using Dual-Exposure Lithography (DEL)

2020

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“…Fu et al [ 37 ] represented SiO 2 -composed nano-honeycomb PC structure by self-assembly polystyrene (PS) pattering to improve LEE and view angle of GaN-based LEDs. Suslik et al [ 38 ] used a multiple exposure process with two-beam interference lithography to define a PC structure on photoresistor and spun liquid polydimethylsiloxane (PDMS) on the patterned photoresistor to form a PC PDMS membrane. The PDMS membrane was then applied to the surface of the LED chip to enhance the electroluminescence (EL) intensity.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Photonic-Crystal-Structured p-GaN Nanorods Fabricated by Polystyrene Nanosphere Lithography Method to Improve the Light Extraction Efficiency of InGaN/GaN Green Light-Emitting Diodes

2021

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We fabricated the photonic-crystal-structured p-GaN (PC-structured p-GaN) nanorods using the modified polystyrene nanosphere (PS NS) lithography method for InGaN/GaN green light-emitting diodes (LEDs) to enhance the light extraction efficiency (LEE). A modified PS NS lithography method including two-times spin-coating processes and the post-spin-coating heating treatment was used to obtain a self-assembly close-packed PS NS array of monolayer as a mask and then a partially dry etching process was applied to PS NS, SiO2, and p-GaN to form PC-structured p-GaN nanorods on the InGaN/GaN green LEDs. The light output intensity and LEE of InGaN/GaN green LEDs with the PC-structured p-GaN nanorods depend on the period, diameter, and height of PC-structured p-GaN nanorods. RSoft FullWAVE software based on the three-dimension finite-difference time-domain (FDTD) algorithm was used to calculate the LEE of InGaN/GaN green LEDs with PC-structured p-GaN nanorods of the varied period, diameter, and height. The optimal period, diameter, and height of PC-structured p-GaN nanorods are 150, 350, and 110 nm. The InGaN/GaN green LEDs with optimal PC-structured p-GaN nanorods exhibit an enhancement of 41% of emission intensity under the driving current of 20 mA as compared to conventional LED.

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“…Photonic crystals can be used to selectively reflect specific frequencies of electromagnetic radiation. It is a significant tool to control the propagation of electromagnetic (EM) waves, which has been widely used in Bragg mirrors, optical waveguide, optical switch, solar cells, sensors and light-emitting diodes (LEDs) [1][2][3][4][5][6][7][8][9][10]. In recent years, there appears to have been great interest in fabricating tunable photonic crystals for real-time and on-demand control of the photonic band structures [11,12].…”

Section: Introductionmentioning

confidence: 99%

Structural Tunable Plasma Photonic Crystals in Dielectric Barrier Discharge

et al. 2020

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We demonstrate a kind of structural tunable plasma photonic crystal in a dielectric barrier discharge by self-organization of the plasma filaments. The symmetry, the lattice constant and the orientations of different plasma photonic crystals can be deliberately controlled by changing the applied voltage. The plasma structures can be tuned from a square lattice to a triangular lattice, the lattice constant is reduced and the crystal orientation varies π6 when the applied voltage is increased. The band diagrams of the plasma photonic crystals under a transverse-magnetic wave have been studied, which shows that the positions and sizes of the band gaps change significantly for different plasma structures. We suggest a flexible way for the fabrication of tunable plasma photonic crystals, which may find wide application in the manipulation of microwaves or terahertz waves.

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Photonic crystal and photonic quasicrystal patterned in PDMS surfaces and their effect on LED radiation properties

Cited by 25 publications

References 23 publications

Fabrication of Tapered 3D Microstructure Arrays Using Dual-Exposure Lithography (DEL)

Fabrication of Tapered 3D Microstructure Arrays Using Dual-Exposure Lithography (DEL)

Investigation of Photonic-Crystal-Structured p-GaN Nanorods Fabricated by Polystyrene Nanosphere Lithography Method to Improve the Light Extraction Efficiency of InGaN/GaN Green Light-Emitting Diodes

Structural Tunable Plasma Photonic Crystals in Dielectric Barrier Discharge

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