Aluminum-doped zinc oxide as anode for organic near-infrared photodetectors

High transparency and low resistivity aluminum-doped zinc oxide (AZO) films were prepared by atomic layer deposition. The AZO films show a transparency of about 80% in the near-infrared (NIR) region and a resistivity of the order of 10(-3) Omega cm. Organic small molecule NIR-photodetectors (NIR-PDs) with AZO as the anode have been demonstrated for the first time with lead phthalocyanine (PbPc) and C-60 as the donor and acceptor, respectively. The optimized NIR-PD exhibited an external quantum efficiency of 6.2% at 760 nm. This result indicated that AZO can be used as the anode for high efficiency NIR-PDs.