Recent Progress on OrganicNear‐InfraredPhotodetectors: Mechanism, Devices, and Applications^†

Abstract

Comprehensive Summary Near infrared light organic photodetectors have attracted tremendous attention due to their tailorable response, ease of processing, compatibility with flexible substrate, room temperature operation and broad applications such as remote sensing, health monitoring, artificial vision, night vision, and so on. Recently, the great improvement obtained on the important figures of merit performances has made organic photodetectors catch up and even surpass those of inorganic photodetectors in some respects. In this review, after a brief illustration of the organic photodetectors' figures of merit performances, we summarize the research progress of panchromatic and narrowband near infrared light organic photodetectors from their working mechanism, strategies to achieve narrowband near infrared light organic photodetectors, to some practical applications. Finally, we discuss the development challenge of the near infrared light organic photodetectors.

Efficient All‐Polymer Photomultiplication‐Type Organic Photodetectors with Prolonged Crystallization Process

“…The optimal PS-blended device has lower dark currents than the control device, indicating that the introduction of PS improves the EQE without sacrificing the dark current of the device. Considering only the shot noise, D can be roughly estimated by using the following equation [34]…”

Controlling Electron/Hole Recombination in Near-Infrared Polymer Phototransistors through an Insulation Medium: A Pathway to Ultrahigh Photosensitivity

“…In addition, the responsivity ( R ) and EQE (the value is equal to G ) are calculated as follows , R = normalΔ I Ph normalP inc EQE = R × h υ q × 100 % where Δ I ph is the photocurrent, P inc is the incident light power, hυ is the incident photon energy, and q is the elementary electron charge.…”

“…μ avg•vg is the average mobility, which is obtained from the average slope of the saturation transfer curves. 34 In addition, the responsivity (R) and EQE (the value is equal to G) are calculated as follows 2,35…”

“…Near-infrared (NIR) polymer phototransistors, characterized by their unique gate structure, long propagation distance of NIR light in tissue, and high accuracy of oximetry in the NIR region, have attracted extensive attention for their potential in wearable pulse oximetry. − However, the narrow band gap (∼1 eV) of NIR polymers leads to a constant injection of electrons from the electrode to the active layer in the dark state. Furthermore, high binding energy Frenkel excitons are easily generated under illumination. , Consequently, NIR phototransistors exhibit a large turn-on voltage ( V o ), a high dark current, and a slow photoresponse, substantially reducing the accuracy of health monitoring data in wearable pulse oximetry.…”

Efficient Ultrathin Self‐Powered Organic Photodetector with Reduced Exciton Binding Energy and Auxiliary Föster Resonance Energy Transfer Processes

“…night vision, optical communication, environmental monitoring, and biomedical imaging. [1][2][3][4][5][6][7][8][9][10][11][12] As an important alternative for traditional inorganic PD technology, especially silicon-based photodetectors, organic photodetectors (OPDs) offer the advantages of tunable detection wavelengths, simplified synthesis, low-cost fabrication, large-area production, and compatibility with lightweight and flexible. [13][14][15][16] Usually, external bias needs to be applied to drive the devices and enhance the photocurrent in organic photodetectors, which limits its operating conditions and environment.…”