scholarly journals Comparative Design Study for Power Reduction in Organic Optoelectronic Pulse Meter Sensor

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 48 ◽  
Author(s):  
Fahed Elsamnah ◽  
Anubha Bilgaiyan ◽  
Muhamad Affiq ◽  
Chang-Hoon Shim ◽  
Hiroshi Ishidai ◽  
...  
Keyword(s):  
Power Consumption ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
The Body ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Design Structure ◽  
Organic Devices ◽  
Organic Optoelectronic

This paper demonstrated a new design structure for minimizing the power consumption of a pulse meter. Monolithic devices composed of a red (625 nm) organic light-emitting diode (OLED) and an organic photodiode (OPD) were fabricated on the same substrate. Two organic devices were designed differently. One had a circle-shaped OLED in the center of the device and was surrounded by the OPD, while the other had the opposite structure. The external quantum efficiency (EQE) of the OLED and the OPD were 7% and 37%, respectively. We evaluated and compared the signal-to-noise ratio (SNR) of the photoplethysmogram (PPG) signal on different parts of the body and successfully acquired clear PPG signals at those positions, where the best signal was obtained from the fingertip at a SNR of about 62 dB. The proposed organic pulse meter sensor was operated successfully with a power consumption of 0.1 mW. Eventually, the proposed organic biosensor reduced the power consumption and improved the capability of the pulse meter for long-term use.

scholarly journals Reflectance-Based Organic Pulse Meter Sensor for Wireless Monitoring of Photoplethysmogram Signal

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 87 ◽  
Author(s):  
Fahed Elsamnah ◽  
Anubha Bilgaiyan ◽  
Muhamad Affiq ◽  
Chang-Hoon Shim ◽  
Hiroshi Ishidai ◽  
...  
Keyword(s):  
Power Consumption ◽  
Structural Design ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Wireless Monitoring ◽  
Organic Light ◽  
Reduced Power Consumption

This paper compares the structural design of two organic biosensors that minimize power consumption in wireless photoplethysmogram (PPG) waveform monitoring. Both devices were fabricated on the same substrate with a red organic light-emitting diode (OLED) and an organic photodiode (OPD). Both were designed with a circular OLED at the center of the device surrounded by OPD. One device had an OLED area of 0.06 cm2, while the other device had half the area. The gap distance between the OLED and OPD was 1.65 mm for the first device and 2 mm for the second. Both devices had an OPD area of 0.16 cm2. We compared the power consumption and signal-to-noise ratio (SNR) of both devices and evaluated the PPG signal, which was successfully collected from a fingertip. The reflectance-based organic pulse meter operated successfully and at a low power consumption of 8 µW at 18 dB SNR. The device sent the PPG waveforms, via Bluetooth low energy (BLE), to a PC host at a maximum rate of 256 kbps data throughput. In the end, the proposed reflectance-based organic pulse meter reduced power consumption and improved long-term PPG wireless monitoring.

A Novel Voltage-Programmed Pixel Circuit with Poly-Si TFTs for AMOLED Displays

2018 ◽  
Vol 27 (14) ◽  
pp. 1850221
Author(s):  
Zunkai Huang ◽  
Li Tian ◽  
Hui Wang ◽  
Songlin Feng
Keyword(s):  
Threshold Voltage ◽  
Light Emitting Diode ◽  
Active Matrix ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Electrical Stress ◽  
Organic Light ◽  
Pixel Circuit ◽  
Display Performance

In this paper, we propose a novel voltage-programmed pixel circuit with polysilicon thin–flim transistors (poly-Si TFTs) for active matrix organic light-emitting diode (AMOLED) displays, which consists of one programming transistor, one driving transistor, four switching transistors and two storage capacitors, respectively. Specifically, the proposed pixel circuit is able to not only efficiently compensate for the threshold variations of TFTs, but also largely suppresses the electrical degradations of the devices caused by the long-term electrical stress. Moreover, the mobility variation of the driving transistor can be compensated as well. The simulation has been performed by HSPICE, and results indicate that the average values of nonuniformities are, respectively, 7.3% as the threshold-voltage varies by [Formula: see text][Formula: see text]V and 2.1%, as the mobility of the driving transistor varies by [Formula: see text]%, both of which are much lower than that of the conventional two-transistor and one-capacitor (2T1C) pixel. Furthermore, since the OLED is reverse-biased during the nonemission phases, the lifetime of OLED will be extended naturally. As a consequence, the proposed pixel circuit can substantially improve the display performance.

scholarly journals Negative Charge Management to Make Fragile Bonds No Longer Fragile towards Electrons for Robust Organic Optoelectronic Materials

2020 ◽  
Author(s):  
Rui Wang ◽  
Qing-Yu Meng ◽  
Yi-Lei Wang ◽  
JUAN QIAO
Keyword(s):  
Negative Charge ◽  
Electronic Materials ◽  
Light Emitting Diode ◽  
Building Blocks ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Intrinsic Stability ◽  
Organic Optoelectronic ◽  
New Perspective ◽  
Device Lifetime

<p>The development of robust organic (opto)electronic devices is mainly depressed by the poor intrinsic stability of organic materials on service. For organic light-emitting diode (OLED) materials, a key parameter for intrinsic stability is the bond-dissociation energy of the most fragile bond (BDE<sub>f</sub>). Although rarely concerned, many OLED molecules have the lowest BDE<sub>f</sub> in anionic states (BDE<sub>f</sub>(−) ∼1.6−2.5 eV), which could be a fatal short-slab for device stability. Here, we confirmed the clear relationship between BDE<sub>f</sub>(−), intrinsic material stability, and device lifetime, and further developed a general and effective strategy to promote BDE<sub>f</sub>(−) ~1 eV for various fragile bonds by introducing appropriate negative charge manager within the molecule. The manager can firmly confine negative-charge and protect fragile bonds, which was verified in typical phosphine-oxide and carbazole derivatives, and backed by newly-designed molecules. This tactic provides a new perspective to reform the vulnerable building blocks for robust organic (opto)electronic materials and devices.<br></p>

scholarly journals Enhanced Electroluminescence Based on a π-Conjugated Heptazine Derivative by Exploiting Thermally Activated Delayed Fluorescence

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Li ◽  
Heqi Gong ◽  
Jincheng Zhang ◽  
Shiyi Zhou ◽  
Li Tao ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Delayed Fluorescence ◽  
Yellow Emission ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Exciplex Formation ◽  
The Matrix ◽  
Organic Optoelectronic

Heptazine derivatives have attracted much attention over the past decade by virtue of intriguing optical, photocatalytic as well as electronic properties in the fields of hydrogen evolution, organic optoelectronic technologies and so forth. Here, we report a simple π-conjugated heptazine derivative (HAP-3DF) possessing an n→π* transition character which exhibits enhanced electroluminescence by exploiting thermally activated delayed fluorescence (TADF). Green-emitting HAP-3DF shows relatively low photoluminescence quantum efficiencies (Φp) of 0.08 in toluene and 0.16 in doped film with bis(2-(diphenylphosphino)phenyl) ether oxide (DPEPO) as the matrix. Interestingly, the organic light-emitting diode (OLED) incorporating 8 wt% HAP-3DF:DPEPO as an emitting layer achieved a high external quantum efficiency (EQE) of 3.0% in view of the fairly low Φp of 0.16, indicating the presence of TADF stemming from n→π* transitions. As the matrix changing from DPEPO to 1,3-di (9H-carbazol-9-yl)benzene (mCP), a much higher Φp of 0.56 was found in doped film accompanying yellow emission. More importantly, enhanced electroluminescence was observed from the OLED containing 8 wt% HAP-3DF:mCP as an emitting layer, and a rather high EQE of 10.8% along with a low roll-off was realized, which should be ascribed to the TADF process deriving from exciplex formation.

scholarly journals Negative Charge Management to Make Fragile Bonds No Longer Fragile towards Electrons for Robust Organic Optoelectronic Materials

2020 ◽  
Author(s):  
Rui Wang ◽  
Qing-Yu Meng ◽  
Yi-Lei Wang ◽  
JUAN QIAO
Keyword(s):  
Negative Charge ◽  
Electronic Materials ◽  
Light Emitting Diode ◽  
Building Blocks ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Intrinsic Stability ◽  
Organic Optoelectronic ◽  
New Perspective ◽  
Device Lifetime

<p>The development of robust organic (opto)electronic devices is mainly depressed by the poor intrinsic stability of organic materials on service. For organic light-emitting diode (OLED) materials, a key parameter for intrinsic stability is the bond-dissociation energy of the most fragile bond (BDE<sub>f</sub>). Although rarely concerned, many OLED molecules have the lowest BDE<sub>f</sub> in anionic states (BDE<sub>f</sub>(−) ∼1.6−2.5 eV), which could be a fatal short-slab for device stability. Here, we confirmed the clear relationship between BDE<sub>f</sub>(−), intrinsic material stability, and device lifetime, and further developed a general and effective strategy to promote BDE<sub>f</sub>(−) ~1 eV for various fragile bonds by introducing appropriate negative charge manager within the molecule. The manager can firmly confine negative-charge and protect fragile bonds, which was verified in typical phosphine-oxide and carbazole derivatives, and backed by newly-designed molecules. This tactic provides a new perspective to reform the vulnerable building blocks for robust organic (opto)electronic materials and devices.<br></p>

scholarly journals Investigation of MEH-PPV OLED Assisted by An IoT Environment Monitoring System

2020 ◽  
Vol 2 (2) ◽  
pp. 36-41
Author(s):  
Ibrahim Attia ◽  
Guang Liang Ong ◽  
Teng Sian Ong ◽  
Chen Hon Nee ◽  
Seong Shan Yap
Keyword(s):  
Monitoring System ◽  
Annealing Temperature ◽  
Light Emitting Diode ◽  
Single Layer ◽  
Environment Monitoring ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Internet Of Things Environment ◽  
Fabrication Parameters

Single layer organic light emitting diode (OLED)devices based on poly{[2-methoxy-5-(-2ethylhexyloxy)-1,4-phenylene]vinylene}(MEH-PPV)are fabricated and studied in this work .There are several factors that affect the performance of the fabricated OLED samples. Some of these factors are related to the fabrication parameters chosen for the OLED fabrication process. The effect of concentration and annealing temperature are investigated. Other environmental factors such as humidity or temperature affect the performance of fabricated OLED samples under long term exposure. An internet of things environment monitoring system (IoT-EMS) is developed to monitor and study the effect of these factors on the performance of the OLED samples. Exposure to humidity is found to severely degrade the samples. In summary, the optimum concentration for MEH-PPV is concluded to be4 mg/ml, and the best annealing temperature is 90C in this study. It is also deduced that humidity of 72-75% caused degradation of the samples in less than 20 hours.

scholarly journals How to Make Fragile Bonds no Longer Fragile Towards Electrons for Robust Organic Optoelectronic Materials

2020 ◽  
Author(s):  
Rui Wang ◽  
Qing-Yu Meng ◽  
Yi-Lei Wang ◽  
JUAN QIAO
Keyword(s):  
Rational Design ◽  
Electronic Materials ◽  
Light Emitting Diode ◽  
Building Blocks ◽  
Close Correlation ◽  
Strong Electron ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Optoelectronic ◽  
Device Lifetime

<p>The development of robust organic (opto)electronic devices is mainly hindered by the chemical deterioration of organic materials on service. For organic light-emitting diode (OLED) materials, a key molecular parameter for intrinsic chemical stability is the bond-dissociation energy of the fragile bond (BDE<sub>f</sub>) with the lowest BDE in the molecule. Although rarely concerned, most OLED molecules have the lowest BDE<sub>f</sub> in negatively charged states (BDE<sub>f</sub>(−), ∼1.6−2.5 eV), which would be a fatal short-slab for device stability. Here, we confirmed the close correlation between BDE<sub>f</sub>(−), intrinsic material stability, and device lifetime. To make fragile bonds no longer fragile towards electrons, we found that introducing strong electron-withdrawing groups with delocalizing structures would be an effective and universal strategy, which was found in typical phosphine-oxide and carbazole module molecules and backed by comparisons in several reported and newly designed molecules. It not only substantially improves BDE<sub>f</sub>(−) by ∼1 eV, but revives the originally vulnerable building blocks, thus largely enriches available groups for rational design of robust OLED and other organic (opto)electronic materials.</p>

scholarly journals Synthesis and Characterization of AIE-Active B–N-Coordinated Phenalene Complexes

2020 ◽  
Vol 02 (03) ◽  
pp. 240-247
Author(s):  
Yubin Fu ◽  
Junzhi Liu ◽  
Zhongbin Wu ◽  
Jan J. Weigand ◽  
Xinliang Feng
Keyword(s):  
Theoretical Calculations ◽  
Light Emitting Diode ◽  
Photophysical Properties ◽  
Stokes Shift ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Optoelectronic Devices ◽  
Emission Behavior ◽  
Promising Application ◽  
Organic Optoelectronic

Organoboron compounds provide a new line to tune the electronic structures of π-conjugated molecules, which is critical to the development of new organic semiconductor materials. In this work, we demonstrate the synthesis of two novel boron–nitrogen (B−N) coordinated phenalene complexes (BNP-PX and BNP-PA) by employing BN phenalene (BNP) as the acceptor unit and phenoxazine/phenylphenazine groups as the donors. Based on single-crystal X-ray analysis, both BNP-PX and BNP-PA possess highly twisted conformations with the dihedral angles of 76.6 ° and 70.5 °, respectively. The photophysical properties of BNP-PX and BNP-PA are elucidated through UV-vis absorption, fluorescence spectroscopy, and theoretical calculations. In addition, BNP-PX exhibits a large Stokes shift (8,033 cm−1) and excellent aggregated-induced emission behavior. The red organic light-emitting diode device was fabricated based on compound BNP-PX, manifesting its promising application in organic optoelectronic devices.

scholarly journals How to Make Fragile Bonds no Longer Fragile Towards Electrons for Robust Organic Optoelectronic Materials

2020 ◽  
Author(s):  
Rui Wang ◽  
Qing-Yu Meng ◽  
Yi-Lei Wang ◽  
JUAN QIAO
Keyword(s):  
Rational Design ◽  
Electronic Materials ◽  
Light Emitting Diode ◽  
Building Blocks ◽  
Close Correlation ◽  
Strong Electron ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Optoelectronic ◽  
Device Lifetime

<p>The development of robust organic (opto)electronic devices is mainly hindered by the chemical deterioration of organic materials on service. For organic light-emitting diode (OLED) materials, a key molecular parameter for intrinsic chemical stability is the bond-dissociation energy of the fragile bond (BDE<sub>f</sub>) with the lowest BDE in the molecule. Although rarely concerned, most OLED molecules have the lowest BDE<sub>f</sub> in negatively charged states (BDE<sub>f</sub>(−), ∼1.6−2.5 eV), which would be a fatal short-slab for device stability. Here, we confirmed the close correlation between BDE<sub>f</sub>(−), intrinsic material stability, and device lifetime. To make fragile bonds no longer fragile towards electrons, we found that introducing strong electron-withdrawing groups with delocalizing structures would be an effective and universal strategy, which was found in typical phosphine-oxide and carbazole module molecules and backed by comparisons in several reported and newly designed molecules. It not only substantially improves BDE<sub>f</sub>(−) by ∼1 eV, but revives the originally vulnerable building blocks, thus largely enriches available groups for rational design of robust OLED and other organic (opto)electronic materials.</p>

scholarly journals Long-Term Reliability Characteristics of OLED Panel and Luminaires for General Lighting Applications

2020 ◽  
Vol 11 (1) ◽  
pp. 74
Author(s):  
Jeungmo Kang ◽  
Yoonhee Cho ◽  
Woojin Jang
Keyword(s):  
Light Emitting Diode ◽  
Light Output ◽  
Color Temperature ◽  
Light Sources ◽  
Operating Voltage ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Reliability Characteristics ◽  
Color Rendering

Organic light-emitting diode is one of the future-proof solid-state-based lighting sources. OLED shows great aesthetic advantages and good color quality without glare. Moreover OLED is a kind of surface light sources naturally. There are some studies on the long-term reliability characteristics of OLED light source. However, these studies focused on the light output degradation of OLED light sources mainly. In this paper, we have investigated the long-term reliability characteristics of OLED panel and luminaires in terms of lumen maintenance, correlated color temperature, color rendering index, and operating voltage. Total twelve OLED panels with four different kinds and six OLED luminaires with two different kinds were analyzed up to six thousand hours and analyzed for the general lighting applications.

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