Polymer infrared photo-detector with high sensitivity up to 1100 nm

En Chen Chen, Shin Rong Tseng, Yu Chiang Chao, Hsin Fei Meng, Chih Feng Wang, Wen Chang Chen, Chian Shu Hsu, Sheng Fu Horng

    Research output: Contribution to journalArticlepeer-review

    19 Citations (Scopus)


    We reported a low band-gap conjugated polymer, poly[2,3-bis(4-(2- ethylhexyloxy)phenyl)-5,7-di(thiophen-2-yl)thieno[3,4-b]pyrazine] (PDTTP), was studied for the near infrared (NIR) photo-detector application. PDTTP shows intense absorption in NIR wavelength (to 1000 nm) and the estimated optical and electrochemical band-gaps of PDTTP are quite small around 1.15 eV and 1.08 eV, respectively. The low band-gap and the extended long wavelength absorption originates from the introduction of alternating TP units when its parent polythieno[3,4-b]pyrazine shows excellent narrow band-gap properties. Therefore, the relatively low band-gap and intense absorption in long wavelength of PDTTP make itself a promising candidate for near-infrared photo-detector. The hole mobility of the PDTTP measured from the bottom contact field effect transistor is around 1.40 × 10-3 cm2/V s with a on/off ratio of 2100. The photo-detector based on bulk hetero-junction PDTTP and (6,6)-phenyl-C61-butyric acid methyl ester blend (PCBM) has the incident photon-to-electron conversion efficiency 28.9% at 1000 nm (-5 V) and 6.2% at 1100 nm (-5 V). This photo-detector can be operated at a high-speed of 1 MHz. The experimental result suggests the potential applications of low band-gap conjugated polymers on near-infrared photo-detectors.

    Original languageEnglish
    Pages (from-to)1618-1622
    Number of pages5
    JournalSynthetic Metals
    Issue number15-16
    Publication statusPublished - 2011 Aug 1


    • Low band-gap
    • Near infrared
    • Photo-detector
    • Polymer

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering
    • Metals and Alloys
    • Materials Chemistry

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