Fig. 3: Optical responses and linearities of organic photodiode for various light sources.

a Schematic diagram of the cross-sectional view of the stack of organic photodiode (OPD). The device structure is Indium tin oxide (ITO)/Zinc oxide (ZnO)/2,5-bis(3-(2-ethylhexyl-5-(trimethylstannyl)thiophen-2-yl)thiazolo[5,4-d]thiazole-2-butyloctyl (PTzNTz-BOBO):[6,6]-Phenyl-C71-butyric acid methyl ester (PC₇₁BM)/Molybdenum oxide (MoO_X)/Ag. b Light intensity dependence of OPD with 1-sun illumination form solar simulator. Light intensity of solar simulator was varied from 0.01 to 1-sun with optical filters. The red dots represent short-circuit current, and the blue dots open-circuit voltage. The red dash line represents a linear fitted line of short-circuit current and light intensity. The blue dash line represents a logarithmically fitted line of open-circuit voltage and light intensity. α represents light intensity exponent of OPD with 1-sun illumination. c External quantum efficiency (EQE) spectra of OPD and Electroluminescence (EL) spectra of polymer light-emitting diode (PLED). The green curve represents EQE spectra of OPD, and the orange curve represents EL spectra of PLED. d J–V characteristics of OPD illuminated by PLED. Optical power of PLED was varied by changing driving voltage of PLED. Each of the devices are stacked together with a face-to-face configuration. The black curve represents current density-voltage dependence of OPD under dark condition, and the bule curves to red curves represent current density-voltage dependences by increasing optical power of PLED. e Light intensity dependence of OPD with PLED illumination. The red dots represent short-circuit current, and the blue dots open-circuit voltage. The red dash line represents a linear fitted line of short-circuit current and light intensity. The blue dash line represents a logarithmically fitted line of open-circuit voltage and light intensity. α represents light intensity exponent of OPD with PLED illumination.