Dual‐Band Organic Photodetectors for Dual‐Channel Optical Communications

Abstract

The dual‐band organic photodetectors (OPDs) detect incoming light selectively in two different bands. This work demonstrates a bias‐switchable dual‐band OPD, achieving a fast‐switching speed of over 1000 times per second and a −3 dB cutoff frequency of > 100 kHz for high‐speed optical communications in two distinct bands, e.g., near‐infrared (NIR) and visible light. Visible‐blind NIR detection with a high responsivity of 435 mA W–1 is realized for the OPDs operated under a small reverse bias of −1.0 V. NIR‐blind visible light detection with a responsivity of 325 mA W–1 is obtained for the OPDs operated under a low forward bias of 1.0 V. Dual‐channel NIR/visible optical communication technique has been demonstrated, providing an opportunity for a plethora of applications in information electronics and the Internet‐of‐Things.

Organic photodiodes: device engineering and applications

“…Both inorganic nanoparticles and quantum dots have been employed to provide additional carrier traps in organic BHJ, which also enables carrier tunneling at the Schottky junction [130]. Since the total current in photomultiplication OPDs is created by the photo-generated carriers as well as those injected via tunneling, a photocurrent gain for an EQE higher than unity can be achieved [39]. Nevertheless, these photomultiplication OPDs typically suffer from relatively large dark current and long response time, thus hindering their practical applications [131,132].…”

“…With tailorable photoelectrical properties, miniaturized spectrometer prototypes were made by integrating customized wavelength-selective OPD pixels into compact modules for handheld or wearable spectrum measurements [35,36]. Fast response with bandwidth up to MHz and some specific photo-response properties of OPDs make them potential in the development of various light communication systems, including indoor navigation and data communication (high indoor photo-generation efficiency) [37], encryption communication (spectral selectivity) [38,39], multichannel visible light communication (multi-wavelength response) [40], and remote control (NIR response) [41].…”

Organic photodetectors based on pentacene single crystals with fast response and flexibility

“…Advanced photodetectors (PDs) are at the core of many technologies and applications, including optical communications, combustion flame monitoring, imaging sensors, night vision, remote controls and medical diagnoses. [1][2][3][4][5] At present, most of the commercial PDs with high sensitivity and fast response are fabricated using inorganic semiconductors, including traditional semiconductors (such as Si, Ge and GaAs), and thirdgeneration wide bandgap semiconductors (such as GaN, and SiC), because of their high mobility and stability. 6,7 However, inorganic materials always suffer from poor strain tolerance and strict preparation conditions, which would not meet the demand for next-generation highperformance, lowcost and flexible optoelectronic devices.…”

Low dark current density in organic photodiodes achieved by reduced trap states of conjugated polymers bearing a fluorinated moiety

“…[4][5][6][7] In addition, optoelectronic devices that detect in the near-infrared range are widely applied in biomedical imaging, light detection and ranging (LiDAR) technology required for autonomous driving of electric vehicles, and optical communication. [8][9][10][11][12] The active layer of photodiodes typically uses inorganic semiconductor materials such as silicon and compound semiconductors. However, the recent advent of wearable electronic technology demands image sensors that have large areas and a flexible form factor.…”

“…4–7 In addition, optoelectronic devices that detect in the near-infrared range are widely applied in biomedical imaging, light detection and ranging (LiDAR) technology required for autonomous driving of electric vehicles, and optical communication. 8–12…”