Inverted near-infrared organic photodetector with oriented lead (II) phthalocyanine molecules via substrate heating

We developed a lead (II) phthalocyanine (PbPc)-based inverted organic photodetector (OPD) detecting near-infrared (NIR) wavelength near 940 nm. Such inverted OPDs can be combined with n-channel silicon-based integrated circuits. Operation near 940 nm is crucial in terms of daylight applications because the intensity of sunlight is low near that wavelength. A spectral response to 1000 nm was achieved by depositing PbPc on a heated C60 layer to form a triclinic rather than a monoclinic phase. This exhibited a much higher responsivity (35.8 mA/W at 960 nm) compared to a device fabricated without substrate heating (8.4 mA/W). The external quantum efficiency also increased from 0.9 to 4.4%.