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The fabrication and characterization of an all polymers‐based bulk heterojunction type organic photodiode having a narrowband response in the near‐infrared spectral region with full width at half‐maxima of 63 nm is reported. The active layer of the photodiode constitutes a 1:1 (by weight) blend of poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b']dithiophene‐2,6‐diyl‐alt‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene‐)‐2‐carboxylate‐2‐6‐diyl)] (PCE10) and poly{[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diy1]‐alt‐5,5′‐(2,2′‐dithiophene)} (N2200) deposited using solution processing. The device exhibits a linear dynamic range of 35 dB, response speed of 893 kHz, and specific‐detectivity of 109 Jones at 808 nm excitation wavelength. The narrowband response is achieved using the charge collection narrowing mechanism in a 2.7 μm thick junction device. [ABSTRACT FROM AUTHOR]

Highly responsive organic photodetectors allow a plethora of applications in fields like imaging, health, security monitoring, etc. Photomultiplication‐type organic photodetectors (PM‐OPDs) are a desirable option due to their internal amplification mechanism. However, for such devices, significant gain and low dark currents are often mutually excluded since large operation voltages often induce high shot noise. Here, a fully vacuum‐processed PM‐OPD is demonstrated using trap‐assisted electron injection in BDP‐OMe:C60 material system. By applying only −1 V, compared with the self‐powered working condition, the responsivity is increased by one order of magnitude, resulting in an outstanding specific detectivity of ≈1013 Jones. Remarkably, the superior detectivity in the near‐infrared region is stable and almost voltage‐independent up to −10 V. Compared with two photovoltaic‐type photodetectors, these PM‐OPDs exhibit the great potential to be easily integrated with state‐of‐the‐art readout electronics in terms of their high responsivity, fast response speed, and bias‐independent specific detectivity. The employed vacuum fabrication process and the easy‐to‐adapt PM‐OPD concept enable seamless upscaling of production, paving the way to a commercially relevant photodetector technology. [ABSTRACT FROM AUTHOR]

A near‐infrared (NIR)‐absorbing conjugated polymer, poly[{2,5‐bis‐(2‐octyldodecyl)‐3,6‐bis‐(thien‐2‐yl)‐pyrrolo[3,4‐c]pyrrole‐1,4‐diyl}‐co‐{2,2′‐(2,1,3‐benzothiadiazole)‐5,5′‐diyl}] (PODTPPD‐BT), which is synthesized via a Stille coupling reaction, can play a dual role (charge transport and sensing) in NIR‐sensing organic phototransistors (OPTRs). The PODTPPD‐BT films, which feature two strong optical absorption peaks at wavelengths (λ) of 830 and 935 nm, possess a highly ordered crystalline state as evidenced by the synchrotron radiation grazing incidence X‐ray diffraction (GIXD) method. The OPTRs with the PODTPPD‐BT layers show typical p‐channel transistor behaviors in the dark, while their best dark performance is measured at a PODTPPD‐BT thickness (t) of 85 nm. The highest overall photocurrent is measured at t = 85 nm under illumination with three monochromatic NIR lights, while the highest photoresponsivity (RC) is obtained for the thickest PODTPPD‐BT layers (t = 145 nm). The flexible OPTRs with the PODTPPD‐BT layers demonstrate stable sensing characteristics upon optical on/off modulations using a high‐power NIR laser diode (λ = 905 nm) used for actual light detection and ranging (LiDAR) systems. [ABSTRACT FROM AUTHOR]