scholarly journals An Ultraviolet Sensor and Indicator Module Based on p–i–n Photodiodes

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4938 ◽  
Author(s):  
Yu-Chieh Chiu ◽  
Pinghui Sophia Yeh ◽  
Tzu-Hsun Wang ◽  
Tzu-Chieh Chou ◽  
Cheng-You Wu ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Uv Light ◽  
Collection Efficiency ◽  
Light Emitting ◽  
Pin Photodiode ◽  
Structural Details ◽  
The Cost ◽  
Pin Photodiodes ◽  
Conversion Efficiencies ◽  
Ultraviolet Sensor

The monolithic integration of an ultraviolet (UV) sensor and warning lamp would reduce the cost, volume, and footprint, in comparison to a hybrid combination of discrete components. We constructed a module comprising a monolithic sensor indicator device based on basic p–i–n (PIN) photodiodes and a transimpedance amplifier. GaN-based light-emitting diodes (LEDs) with an indium-tin oxide (ITO) current-spreading layer and PIN photodiodes without ITO deposition on the light-receiving area, were simultaneously fabricated. The resultant incident photon-to-electron conversion efficiencies of the PIN photodiodes at UV wavelengths were significantly higher than those of the reverse-biased LEDs. The photocurrent signals of the PIN photodiode were then converted to voltage signals to drive an integrated visible LED, which functioned as an indicator. The more the ambient UV-light intensity exceeded a specified level, the brighter the glow of the LED. The responsivities of 0.20 and 0.16 A/W were obtained at 381 and 350 nm, respectively, under a bias voltage of 5 V. We also addressed the epitaxial structural details that can affect the collection efficiency of the photocurrent generated by UV light absorption. The crosstalk between the PIN photodiode and LEDs (of various center-to-center distances) was measured.

scholarly journals Enhanced light output power of near UV light emitting diodes with graphene / indium tin oxide nanodot nodes for transparent and current spreading electrode

2011 ◽  
Vol 19 (23) ◽  
pp. 23111 ◽  
Author(s):  
Tae Hoon Seo ◽  
Kang Jea Lee ◽  
Ah Hyun Park ◽  
Chang-Hee Hong ◽  
Eun-Kyung Suh ◽  
...  
Keyword(s):  
Output Power ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Light Output ◽  
Light Output Power ◽  
Current Spreading ◽  
Light Emitting

Enhanced light output of GaN-based near-UV light-emitting diodes by using nanopatterned indium tin oxide electrodes

2006 ◽  
Vol 21 (5) ◽  
pp. 594-597 ◽  
Author(s):  
Hyun-Gi Hong ◽  
Seok-Soon Kim ◽  
Dong-Yu Kim ◽  
Takhee Lee ◽  
June-O Song ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Light Output ◽  
Light Emitting ◽  
Oxide Electrodes

Injecting Inter-Layers and the Built-in Potential of Blue Polymer Light-Emitting Diodes

2000 ◽  
Vol 660 ◽  
Author(s):  
Thomas M. Brown ◽  
Ian S. Millard ◽  
David J. Lacey ◽  
Jeremy H. Burroughes ◽  
Richard H. Friend ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Basic Structure ◽  
Thin Layers ◽  
Carrier Injection ◽  
Semiconducting Polymer ◽  
Light Emitting ◽  
Physical Mechanisms ◽  
Organic Solid ◽  
Polymer Light Emitting Diodes

ABSTRACTThe semiconducting-polymer/injecting-electrode heterojunction plays a crucial part in the operation of organic solid state devices. In polymer light-emitting diodes (LEDs), a common fundamental structure employed is Indium-Tin-Oxide/Polymer/Al. However, in order to fabricate efficient devices, alterations to this basic structure have to be carried out. The insertion of thin layers, between the electrodes and the emitting polymer, has been shown to greatly enhance LED performance, although the physical mechanisms underlying this effect remain unclear. Here, we use electro-absorption measurements of the built-in potential to monitor shifts in the barrier height at the electrode/polymer interface. We demonstrate that the main advantage brought about by inter-layers, such as poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) (PEDOT:PSS) at the anode and Ca, LiF and CsF at the cathode, is a marked reduction of the barrier to carrier injection. The electro- absorption results also correlate with the electroluminescent characteristics of the LEDs.

Controlled Injection of Holes into ALQ3 Based Oleds by Means of An Oxidized Transport Layer

2001 ◽  
Vol 708 ◽  
Author(s):  
Mathew K. Mathai ◽  
Keith A. Higginson ◽  
Bing R. Hsieh ◽  
Fotios Papadimitrakopoulos
Keyword(s):  
Indium Tin Oxide ◽  
Oxidative Degradation ◽  
Transport Layer ◽  
Hole Injection ◽  
Carrier Injection ◽  
Salt Loading ◽  
Light Emitting ◽  
Hole Transporting ◽  
Intrinsic Degradation ◽  
Variable Conductivity

ABSTRACTIn this paper we report a method for tuning the extent of hole injection into the active light emitting tris- (8-hydroxyquinoline) aluminum (Alq3) layer in organic light emitting diodes (OLEDs). This is made possible by modifying the indium tin oxide (ITO) anode with an oxidized transport layer (OTL) comprising a hole transporting polycarbonate of N,N'-bis(3-hydroxymethyl)-N,N'-bis(phenyl) benzidine and diethylene glycol (PC-TPB-DEG) doped with varying concentrations of antimonium hexafluoride salt of N,N,N',N'-tetra-p-tolyl-4,4'-biphenyldiamine (TMTPD+ SbF6-). The conductivity of the OTL can be changed over three orders of magnitude depending on salt loading. The analysis of hole and electron current variations in these devices indicates that optimizing the conductivity of the OTL enables the modulation of hole injection into the Alq3 layer. The bipolar charge transport properties for OLEDs in which the interfacial carrier injection barriers have been minimized, are governed by the conductivities of the respective layers and in this case it is shown that the variable conductivity of the OTL does allow for better control of the same. Accordingly, varying the concentration of holes in the device indicates that beyond an optimum concentration of holes, further hole injection results in the formation of light quenching cationic species and the initiation of oxidative degradation processes in the Alq3 layer, thus accelerating the intrinsic degradation of these devices. The variable conductivity of the OTL can hence be used to minimize the occurrence of these processes.

Performance of vertical type deep UV light-emitting diodes depending on the Ga-face n-contact hole density

2021 ◽  
Vol 118 (23) ◽  
pp. 231102
Author(s):  
Youn Joon Sung ◽  
Dong-Woo Kim ◽  
Geun Young Yeom ◽  
Kyu Sang Kim
Keyword(s):  
Light Emitting Diodes ◽  
Uv Light ◽  
Hole Density ◽  
Light Emitting ◽  
Deep Uv

New Results on Electroluminescence from Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
Peter Steiner ◽  
Frank Kozlowski ◽  
Hermann Sandmaier ◽  
Walter Lang
Keyword(s):  
Porous Silicon ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Green Light ◽  
Light Emitting ◽  
Porous Region ◽  
First Results

ABSTRACTFirst results on light emitting diodes in porous silicon were reported in 1991. They showed a quantum efficiency of 10-7 to 10-5 and an orange spectrum. Over the last year some progress was achieved:- By applying UV-light during the etching blue and green light emitting diodes in porous silicon are fabricated.- When a p/n junction is realized within the porous region, a quantum efficiency of 10-4 is obtained.

scholarly journals Simple Synthesis of Red Iridium(III) Complexes with Sulfur-Contained Four-Membered Ancillary Ligands for OLEDs

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2599
Author(s):  
Meng-Xi Mao ◽  
Fang-Ling Li ◽  
Yan Shen ◽  
Qi-Ming Liu ◽  
Shuai Xing ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Quantum Yields ◽  
Rapid Preparation ◽  
Maximum Brightness ◽  
Ancillary Ligands ◽  
Light Emitting ◽  
Maximum Current ◽  
Electron Donating Groups ◽  
Sulfur Containing ◽  
Main Ligand

Phosphorescent iridium(III) complexes have been widely researched for the fabrication of efficient organic light-emitting diodes (OLEDs). In this work, three red Ir(III) complexes named Ir-1, Ir-2, and Ir-3, with Ir-S-C-S four-membered framework rings, were synthesized efficiently at room temperature within 5 min using sulfur-containing ancillary ligands with electron-donating groups of 9,10-dihydro-9,9-dimethylacridine, phenoxazine, and phenothiazine, respectively. Due to the same main ligand of 4-(4-(trifluoromethyl)phenyl)quinazoline, all Ir(III) complexes showed similar photoluminescence emissions at 622, 619, and 622 nm with phosphorescence quantum yields of 35.4%, 50.4%, and 52.8%, respectively. OLEDs employing these complexes as emitters with the structure of ITO (indium tin oxide)/HAT-CN (dipyra-zino[2,3-f,2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile, 5 nm)/TAPC (4,4′-cyclohexylidenebis[N,N-bis-(4-methylphenyl)aniline], 40 nm)/TCTA (4,4″,4″-tris(carbazol-9-yl)triphenylamine, 10 nm)/Ir(III) complex (10 wt%): 2,6DCzPPy (2,6-bis-(3-(carbazol-9-yl)phenyl)pyridine, 10 nm)/TmPyPB (1,3,5-tri(mpyrid-3-yl-phenyl)benzene, 50 nm)/LiF (1 nm)/Al (100 nm) achieved good performance. In particular, the device based on complex Ir-3 with the phenothiazine unit showed the best performance with a maximum brightness of 22,480 cd m−2, a maximum current efficiency of 23.71 cd A−1, and a maximum external quantum efficiency of 18.1%. The research results suggest the Ir(III) complexes with a four-membered ring Ir-S-C-S backbone provide ideas for the rapid preparation of Ir(III) complexes for OLEDs.

scholarly journals Change in Interface Characteristics of ITO Modified with n-decyltrimethoxysilane

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 645
Author(s):  
Myung-Gyun Baek ◽  
Johng-Eon Shin ◽  
Dong-Hyun Hwang ◽  
Sung-Hoon Kim ◽  
Hong-Gyu Park ◽  
...  
Keyword(s):  
Contact Angle ◽  
Work Function ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Deposition Time ◽  
Interfacial Properties ◽  
Average Roughness ◽  
Light Emitting ◽  
Force Microscopy ◽  
Angle Measurements

Herein, we examined changes in the interfacial properties of organic light-emitting diodes when n-decyltrimethoxysilane (CH3SAM) was deposited on the surface of an indium tin oxide (ITO) electrode for various deposition times. It was revealed that the interfacial properties varied with deposition time. As the latter increased, so did the measured value of the contact angle, and ITO substrate exhibited a lower wettability. The contact angle measurements for bare ITO at 1, 10, 30, and 90 min were 57.41°, 63.43°, 73.76°, 81.47°, respectively, and the highest value obtained was 93.34°. In addition, the average roughness and work function of the ITO were measured using atomic force microscopy and X-ray photoelectron spectroscopy. As the deposition time of CH3SAM on the ITO substrates increased, it was evident that the former was well aligned with the latter, improving surface modification. The work function of CH3SAM, modified on the ITO substrates, improved by approximately 0.11 eV from 5.05–5.16 eV. The introduction of CH3SAM to the ITO revealed the ease of adjustment of the characteristics of ITO substrates.

scholarly journals Methods of Disinfecting Stethoscopes: Systematic Review

2020 ◽  
Vol 17 (6) ◽  
pp. 1856 ◽  
Author(s):  
Margherita Napolitani ◽  
Daiana Bezzini ◽  
Fulvio Moirano ◽  
Corrado Bedogni ◽  
Gabriele Messina
Keyword(s):  
Systematic Review ◽  
English Language ◽  
Light Emitting Diode ◽  
Bacterial Load ◽  
Silver Ions ◽  
Light Emitting ◽  
Disinfection Methods ◽  
Mesh Terms ◽  
Healthcare Associated ◽  
The Cost

The aim of this systematic review was to investigate the effectiveness of various disinfection methods available for stethoscopes. In March 2019, we performed a search in PubMed and Scopus using the search terms: “reducing stethoscopes contamination” and “disinfection stethoscopes”; the Mesh terms used in PubMed were “Decontamination/methods” or “Disinfection/methods” and “Stethoscopes/microbiology”. Selection criteria were: English language; at least one disinfection method tested. A total of 253 publications were screened. After title, abstract, and full-text analysis, 17 papers were included in the systematic review. Ethanol at 90%, Ethanol-Based Hands Sanitizer (EBHS), triclosan, chlorhexidine, isopropyl alcohol, 66% ethyl alcohol, sodium hypochlorite, and benzalkonium chloride have been proven to lower the presence of bacteria on stethoscopes’ surfaces. In addition, alcohol wipes show effective results. A wearable device emitting ultraviolet C by Light-Emitting Diode (LED) resulted efficacious against common microorganisms involved in Healthcare Associated Infections. The cover impregnated with silver ions seemed to be associated with significantly higher colony counts. Instead, copper stethoscopes surface reduced bacterial load. The disinfection of stethoscopes appears to be essential. There are many valid methods available; the choice depends on various factors, such as the cost, availability, and practicality.

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