Solution-Processed Self-Powered Panchromatic Organic Photodiode and Its Application in Biomedical Devices

Abstract

Non-fullerene acceptor (NFA)-based optoelectronic devices have received great research interest because of their unique optoelectronic characteristics like tunable bandgap, strong near-infrared (NIR) light absorption, and enhanced stability. However, the demonstration of a self-powered NIR broadband photodiode with excellent photoresponse and low dark current density comparable to that of commercial inorganic counterpart remains a challenge. Herein, the high-performance solution-processed self-powered organic broadband photodiode is demonstrated by using a narrow bandgap NFA with a low dark current density (J d) of 1.05 nA/cm2 at 0 V. The dark leakage current of the device is greatly improved by adopting a “thick junction” strategy, and the optimized device exhibits a J d of 6.5 nA/cm2 even at a moderate applied bias voltage of −1.5 V. The devices exhibit more than 70% external quantum efficiency in the 550–830 nm wavelength (λ) range and a specific detectivity of 2.65 × 1012 jones at λ ∼ 770 nm under the self-powered mode of operation. The fabricated photodetector is used in photoplethysmography (PPG) measurement, demonstrating its application in real-time heart-rate monitoring and pulse oximetry.

Flexible Organic Photodetectors with Mechanically Robust Zinc Oxide Nanoparticle Thin Films

“…Notably, these values are similar to those of the recently reported OPDs (Table S4). − However, the R and D * of the flexible OPDs fabricated with the ZnO-NP and ZnO-NP:KBr ETLs/HBLs were gradually decreased after bending 500 and 1000 times at r = 4.0 mm, whereas the ZnO-NP:DFPBr-6 device produced almost identical R and D * regardless of bending cycles (Figure d). The R values of the ZnO-NP and ZnO-NP:KBr devices were decreased to 0.06 and 0.02 A/W corresponding to 85 and 95% reductions, respectively, after bending 1000 times at r = 4.0 mm (Table S3).…”

Synthesis and characterization of a copper(II) phthalocyanine‐based dye for organic photodetectors

“…V OC versus P light was plotted as shown in Figure 2e. The degree of trap-assisted recombination can be evaluated by n value as shown in the following Equation (3), where K B is the Boltzmann constant, and T is the absolute temperature. The nK B T/q value is related to degree of trap-assisted recombination, and closer to 1 indicates smaller trapassisted recombination.…”

“…Organic photodetectors (OPDs) have been rapidly developed for decades due to light weight, low production cost, flexibility, controllable energy band gap, low voltage operation, and solution-processibility. [1][2][3][4][5][6] Thus, OPDs are regarded to be one of the most promising printable devices for the portable and wearable optical communication system and image sensors. [7][8][9] As light-absorbing materials, numerous types of materials have been developed and the most successful materials are conjugated polymers.…”

Copper Nanoparticles Enhancing Organic Light-Emitting Diodes of All Colors

“…59 Joseph et al reported that panchromatic LED can be utilized as a light source for heart rate sensing. 60 Hence, it would be extremely valuable in enabling organic LEDs with all colors as well as medical application viability if a single nanoparticle can be made of nonprecious metals and meanwhile extend the enhancement to the red or even NIR region.…”

“…Lee reported that panchromatic LED display screen not only has the characteristics of high contrast but also is soft in displayed color and has an effect closer to the visual high-definition effect . Joseph et al reported that panchromatic LED can be utilized as a light source for heart rate sensing . Hence, it would be extremely valuable in enabling organic LEDs with all colors as well as medical application viability if a single nanoparticle can be made of nonprecious metals and meanwhile extend the enhancement to the red or even NIR region.…”