Confined deep red light-detecting organic phototransistors with polymer gate-sensing layers consisting of indacenothiophene and dinitrobenzothiadiazole units

초록

Here we report a novel conjugated polymer with deep red-light absorption, consisting of indacenothiophene (IDTT) and dinitrobenzothiadiazole (DNBT) units, which can be used as a gate-sensing layer (GSL) in organic phototransistors (OPTRs). The PIDTT-DNBT polymer was synthesized by the Stille coupling reaction between the IDTT monomer with tin end groups and the DNBT monomer with bromine end groups. The PIDTT-DNBT films showed two pronounced optical absorptions in the wavelength (lambda) ranges of 350-470 nm and 470-800 nm and the highest occupied molecular orbital (HOMO) energy of -5.9 eV. The OPTRs with the PIDTT-DNBT GSLs operated in p-channel modes and exhibited noticeable photo-sensing performances under the illumination of three monochromatic lights (lambda = 550, 670, and 700 nm). When visible light-cutting layers (VLCLs) were applied, the OPTRs with the PIDTT-DNBT GSLs could only sense deep-red light with a narrow spectral range of lambda = 650-800 nm in the absence of other visible light interferences. A newly synthesized PIDTT-DNBT polymer acts as an efficient gate-sensing layer (GSL) in organic phototransistors that can detect a confined deep red light in the presence of a visible light-cut layer (VLCL).

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