Inorganic Semiconductors for Light‐emitting Diodes

Schubert, E. Fred; Gessmann, Th.; Kim, Jong Kyu

doi:10.1002/3527607986.ch1

Cited by 40 publications

(54 citation statements)

References 96 publications

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“…Sub-bandgap turn-on at room temperature was commonly observed for the vacuum-deposited high-efficiency inorganic LEDs with ohmic contacts. 149 The performance of solution-processed OLEDs can be optimized by tuning the properties of oxide-nanocrystal ETLs. Here we selected a few examples of LEDs using F8BT as an emissive material and ZnO nanocrystals as ETLs to highlight the importance of controlling the interface of emissive organics/oxide nanocrystals.…”

Section: Solution-processed Organic Leds (Oleds)mentioning

confidence: 99%

Colloidal metal oxide nanocrystals as charge transporting layers for solution-processed light-emitting diodes and solar cells

et al. 2017

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Colloidal metal oxide nanocrystals offer a unique combination of excellent low-temperature solution processability, rich and tuneable optoelectronic properties and intrinsic stability, which makes them an ideal class of materials as charge transporting layers in solution-processed light-emitting diodes and solar cells. Developing new material chemistry and custom-tailoring processing and properties of charge transporting layers based on oxide nanocrystals hold the key to boosting the efficiency and lifetime of all-solution-processed light-emitting diodes and solar cells, and thereby realizing an unprecedented generation of high-performance, low-cost, large-area and flexible optoelectronic devices. This review aims to bridge two research fields, chemistry of colloidal oxide nanocrystals and interfacial engineering of optoelectronic devices, focusing on the relationship between chemistry of colloidal oxide nanocrystals, processing and properties of charge transporting layers and device performance. Synthetic chemistry of colloidal oxide nanocrystals, ligand chemistry that may be applied to colloidal oxide nanocrystals and chemistry associated with post-deposition treatments are discussed to highlight the ability of optimizing processing and optoelectronic properties of charge transporting layers. Selected examples of solution-processed solar cells and light-emitting diodes with oxide-nanocrystal charge transporting layers are examined. The emphasis is placed on the correlation between the properties of oxide-nanocrystal charge transporting layers and device performance. Finally, three major challenges that need to be addressed in the future are outlined. We anticipate that this review will spur new material design and simulate new chemistry for colloidal oxide nanocrystals, leading to charge transporting layers and solution-processed optoelectronic devices beyond the state-of-the-art.

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Section: Solution-processed Organic Leds (Oleds)mentioning

confidence: 99%

Colloidal metal oxide nanocrystals as charge transporting layers for solution-processed light-emitting diodes and solar cells

et al. 2017

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“…The mechanism of phototherapy is currently accepted to a mitochondrial electron transport chain that affects photostimulatory effects in a cell [2]. In phototherapy or photodynamic therapy devices, light-emitting diodes (LEDs), capable of generating various wavelengths, have been considered as an alternative light source to fluorescent tube, halogen lamp, and laser beam [3]. LEDs in the visible wavelength (400-600 nm) are applicable as a therapeutic light source to treat skin diseases, cancer cells, and muscle pain because they suppress intercellular signal transduction and metastasis of cancer cells via thermal effects [4,5].…”

Section: Introductionmentioning

confidence: 99%

A Macro Lens-Based Optical System Design for Phototherapeutic Instrumentation

Choi

Choe

Ryu

2019

Sensors

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Light emitting diode (LED) and ultrasound have been powerful treatment stimuli for tumor cell growth due to non-radiation effects. This research is the first preliminary study of tumor cell suppression using a macro-lens-supported 460-nm LED combined with high-frequency ultrasound. The cell density, when exposed to the LED combined with ultrasound, was gradually reduced after 30 min of induction for up to three consecutive days when 48-W DC, 20-cycle, and 50 Vp-p sinusoidal pulses were applied to the LEDs through a designed macro lens and to the ultrasound transducer, respectively. Using a developed macro lens, the non-directional light beam emitted from the LED could be localized to a certain spot, likewise with ultrasound, to avoid additional undesirable thermal effects on the small sized tumor cells. In the experimental results, compared to LED-only induction (14.49 ± 2.73%) and ultrasound-only induction (13.27 ± 2.33%), LED combined with ultrasound induction exhibited the lowest cell density (6.25 ± 1.25%). Therefore, our measurement data demonstrated that a macro-lens-supported 460-nm LED combined with an ultrasound transducer could possibly suppress early stage tumor cells effectively.

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“…Compared to lasers, LEDs’ divergent light property can critically lower detection sensitivity [ 19 ]. In addition, a typical LED-based system requires the use of a more complex optical lens setup compared to a laser-based system [ 20 ]. The intensity of the LED light is also much lower than the laser [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, a typical LED-based system requires the use of a more complex optical lens setup compared to a laser-based system [ 20 ]. The intensity of the LED light is also much lower than the laser [ 20 ]. Therefore, the received echo signals when using an LED are relatively lower than when using a laser such that ultrasound transducers with low sensitivity are not suitable for opto–ultrasound instruments.…”

Section: Introductionmentioning

confidence: 99%

Development of a Multiwavelength Visible-Range-Supported Opto–Ultrasound Instrument Using a Light-Emitting Diode and Ultrasound Transducer

Choi

Yeom

Ryu

2018

Sensors

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A new multiwavelength visible-range-supported opto–ultrasound instrument using a light-emitting diode and ultrasound transducer was developed in order to produce multiwavelength visible light with minimized color aberration errors, and detect ultrasound signals emitted from the target. In the instrument, the developed optical systems can provide multiwavelength optical transmission with low optical aberration within 10-cm ranges that are reasonably flat in the modulation transfer function at spatial frequencies of 20 and 40 lp/mm, except at the end of the diagonal edge of the samples. To assess the instrument capability, we performed pulse–echo responses with Thunnus obesus eye samples. Focused red, green, blue and white light rays from an integrated red, green and blue LED source were produced, and echo signal amplitudes of 33.53, 34.92, 38.74 and 82.54 mV, respectively, were detected from the Thunnus obesus eye samples by a 10-MHz focused ultrasound transducer. The center frequencies of the echo signal when producing red, green, blue and white LED light in the instrument were 9.02, 9.05, 9.21 and 8.81 MHz, respectively. From these tests, we verify that this instrument can combine red, green and blue LED light to cover different wavelengths in the visible-light range and detect reasonable echo amplitudes from the samples.

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Inorganic Semiconductors for Light‐emitting Diodes

Cited by 40 publications

References 96 publications

Colloidal metal oxide nanocrystals as charge transporting layers for solution-processed light-emitting diodes and solar cells

Colloidal metal oxide nanocrystals as charge transporting layers for solution-processed light-emitting diodes and solar cells

A Macro Lens-Based Optical System Design for Phototherapeutic Instrumentation

Development of a Multiwavelength Visible-Range-Supported Opto–Ultrasound Instrument Using a Light-Emitting Diode and Ultrasound Transducer

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