Fig. 1. (a) Structure diagram of flexible OPDs with a reflective Ag electrode and an Ag or AGA semitransparent electrode. (b) Reflectivity characteristics of the Ag film and the AGA film. (c) Absorptance spectra of the photoactive layers consisting of CuPc:C60 placed in different device architectures; the blue line represents the active layer without any electrodes, the black line corresponds to the photoactive layer placed in a device with a top electrode of Ag, and the red line indicates the photoactive layer placed in a device with a top electrode of AGA.

Fig. 2. (a) EQE characteristics of devices Ag and AGA with a device structure: Ag  (100  nm)/MoO3  (5  nm)/CuPc(50  nm)/CuPc:C60(50%,20  nm)/C60 (40, 60, 80 nm)/BCP (10 nm)/Bphen (30 nm)/Ag or AGA (25 nm). The solid curves in the graph depict the characteristics of the AGA device with varying thicknesses of C60, whereas the dashed curves represent the Ag device. The red, blue, and green lines, respectively, represent the EQE characteristics of the devices with C60 thicknesses of 40 nm, 60 nm, and 80 nm. (b) Absorptance spectra of devices with C60 thicknesses of 40 nm, 60 nm, and 80 nm.

Fig. 3. AFM images and schematic diagram of film growth modes of (a) 10 nm Ag (10 nm) and (b) 10 nm AGA consisting of 1 nm Ag/1 nm Ge/8 nm Ag. SEM images of (c) 10 nm Ag and (d) 10 nm AGA consisting of 1 nm Ag/1 nm Ge/8 nm Ag. (e) Transmittance and absorptance spectra of the AGA films. The red, blue, and green lines, respectively, correspond to AGA films with thicknesses of 10 nm, 15 nm, and 25 nm, respectively. The 10 nm film consists of 1 nm Ag/1 nm Ge/8 nm Ag, the 15 nm film consists of 4 nm Ag/1 nm Ge/10 nm Ag, and the 25 nm film consists of 15 nm Ag/5 nm Ge/5 nm Ag. (f) EQE characteristics of devices with the AGA films with thicknesses of 10 nm, 15 nm, and 25 nm. Its device structure is PET/Ag (100  nm)/MoO3 (5 nm)/CuPc (20  nm)/CuPc:C60(50  nm)/C60(20  nm)/BCP (10 nm)/Bphen (30 nm)/AGA.

Fig. 4. (a) EQE variation of the flexible OPDs after bending. The flexible device ITO has the same structure as the flexible device AGA, except for the ITO anode and the 100 nm Ag cathode. The insets show the device level diagram. (b) Current density-voltage characteristics of flexible device ITO and flexible device AGA. Imaging of (c) the letter “L” and (d) symbol representing a “transverse line” using 2×2 arrays of AGA-based and ITO-based devices, based on photo-to-dark current ratios. The left side shows the schematic diagram, while the right side displays the experimental results. (e) Imaging of a symbol representing a “transverse line” using 2×2 arrays of AGA-based devices: before and after 100 bends, based on photo-to-dark current ratios.

Fig. 5. (a) Simulated electric field intensity |E| and (b) power dissipation characteristics of the AGA-based and the ITO-based devices. The inset shows the schematic diagram of the used simulation model for the calculation of the power dissipation characteristics. (c) Photocurrent characteristics of the organic photodetector with a 10 nm AGA film after exposure to ambient air for varying durations.