Improved Dark Current Properties in Bi-Layer Structured Organic Photodetectors

2013 ◽  
Vol 650 ◽  
pp. 54-57 ◽  
Author(s):  
Naoki Ohtani ◽  
Shouta Majima
Keyword(s):  
Dark Current ◽  
Near Infrared ◽  
Layer Structure ◽  
Wide Bandgap ◽  
Electron Blocking Layer ◽  
Wet Process ◽  
Optical Sensitivity ◽  
Nir Absorption ◽  
Communication Devices ◽  
Organic Photodetectors

Organic photodiodes operating in the near-infrared (NIR) region with an operating wavelength of about 850 nm, which corresponds to GaAs-based optical devices, were fabricated by wet process. In the active layer, Copper(II)5,9,14,18,23,27,32,36-octabutoxy-2,3-naphthalocyanine was used as NIR absorption material. A wide-bandgap polymer was doped to decrease the dark current, and an n-type organic semiconductor was doped to increase optical sensitivity. To decrease the dark current further, an electron-blocking layer was added onto the anode. This bi-layer structure was found to be very useful for decreasing the dark current. We also evaluated the on/off ratio, which is very important for application to optical communication devices.

Molecular doping of near-infrared organic photodetectors for photoplethysmogram sensors

2021 ◽  
Author(s):  
Binghao Wang ◽  
Alberto D. Scaccabarozzi ◽  
Haoyang Wang ◽  
Mari Koizumi ◽  
Mohamad Insan Nugraha ◽  
...  
Keyword(s):  
Pulse Rate ◽  
Dark Current ◽  
Near Infrared ◽  
Environmental Stability ◽  
Molecular Doping ◽  
Organic Photodetectors

This study introduces three different molecular dopants for near-infrared organic photodetectors. The doped organic photodetectors exhibit low dark current, high detectivity and good environmental stability, and can be used for pulse rate monitoring.

Vacuum‐Processed Small Molecule Organic Photodetectors with Low Dark Current Density and Strong Response to Near‐Infrared Wavelength

2020 ◽  
Vol 8 (17) ◽  
pp. 2000519 ◽  
Author(s):  
Chih‐Chien Lee ◽  
Richie Estrada ◽  
Ya‐Ze Li ◽  
Sajal Biring ◽  
Nurul Ridho Al Amin ◽  
...  
Keyword(s):  
Small Molecule ◽  
Current Density ◽  
Dark Current ◽  
Near Infrared ◽  
Dark Current Density ◽  
Strong Response ◽  
Infrared Wavelength ◽  
Organic Photodetectors

scholarly journals Reverse dark current in organic photodetectors and the major role of traps as source of noise

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jonas Kublitski ◽  
Andreas Hofacker ◽  
Bahman K. Boroujeni ◽  
Johannes Benduhn ◽  
Vasileios C. Nikolis ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Spectral Density ◽  
Dark Current ◽  
Near Infrared ◽  
Low Cost ◽  
Limiting Factor ◽  
Noise Spectral Density ◽  
Infrared Sensing ◽  
Donor Acceptor ◽  
Organic Photodetectors

AbstractOrganic photodetectors have promising applications in low-cost imaging, health monitoring and near-infrared sensing. Recent research on organic photodetectors based on donor–acceptor systems has resulted in narrow-band, flexible and biocompatible devices, of which the best reach external photovoltaic quantum efficiencies approaching 100%. However, the high noise spectral density of these devices limits their specific detectivity to around 1013 Jones in the visible and several orders of magnitude lower in the near-infrared, severely reducing performance. Here, we show that the shot noise, proportional to the dark current, dominates the noise spectral density, demanding a comprehensive understanding of the dark current. We demonstrate that, in addition to the intrinsic saturation current generated via charge-transfer states, dark current contains a major contribution from trap-assisted generated charges and decreases systematically with decreasing concentration of traps. By modeling the dark current of several donor–acceptor systems, we reveal the interplay between traps and charge-transfer states as source of dark current and show that traps dominate the generation processes, thus being the main limiting factor of organic photodetectors detectivity.

scholarly journals The Effect of Nitrogen Incorporation on the Optical Properties of Si-Rich a-SiCx Films Deposited by VHF PECVD

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 637
Author(s):  
Hongliang Li ◽  
Zewen Lin ◽  
Yanqing Guo ◽  
Jie Song ◽  
Rui Huang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Chemical Vapor ◽  
Wide Bandgap ◽  
Nonradiative Recombination ◽  
Very High Frequency ◽  
N Content ◽  
High Frequency Plasma ◽  
Frequency Plasma ◽  
N Incorporation

The influence of N incorporation on the optical properties of Si-rich a-SiCx films deposited by very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) was investigated. The increase in N content in the films was found to cause a remarkable enhancement in photoluminescence (PL). Relative to the sample without N incorporation, the sample incorporated with 33% N showed a 22-fold improvement in PL. As the N content increased, the PL band gradually blueshifted from the near-infrared to the blue region, and the optical bandgap increased from 2.3 eV to 5.0 eV. The enhancement of PL was suggested mainly from the effective passivation of N to the nonradiative recombination centers in the samples. Given the strong PL and wide bandgap of the N incorporated samples, they were used to further design an anti-counterfeiting label.

Strong dark current suppression in flexible organic photodetectors by carbon nanotube transparent electrodes

Nano Today ◽  
2021 ◽  
Vol 37 ◽  
pp. 101081
Author(s):  
Woongsik Jang ◽  
Byung Gi Kim ◽  
Seungju Seo ◽  
Ahmed Shawky ◽  
Min Soo Kim ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Dark Current ◽  
Transparent Electrodes ◽  
Organic Photodetectors

scholarly journals Stacked Dual‐Wavelength Near‐Infrared Organic Photodetectors

2020 ◽  
pp. 2001784
Author(s):  
Yazhong Wang ◽  
Bernhard Siegmund ◽  
Zheng Tang ◽  
Zaifei Ma ◽  
Jonas Kublitski ◽  
...  
Keyword(s):  
Near Infrared ◽  
Dual Wavelength ◽  
Organic Photodetectors
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