Non-power-driven organic photodiode via junction engineering

Here we introduce a junction engineering approach to realize a high performance non-power-driven organic photodiode. To overcome the external power source dependency of conventional photodiodes, in this work, we try not only to implement an inherently large built-in-potential of the junction but also to utilize an inherently low charge carrier concentration of the semiconductor. The strategically designed ITO/plasma-treated ZnO/poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV)/MoO3/Ag geometry showed near-ideal Schottky junction properties with a high zero-bias built-in potential of 0.54 eV, leading to a zero-bias depletion width of 470 nm. As a result, a green-selective polymeric photodiode with high zero-bias detectivity up to 5 × 1011 Jones and a low noise equivalent power of 2.98 × 10−12 W Hz−1/2 are demonstrated, revealing the possibility of a thin film, color-selective and non-power-driven polymeric photodiode for battery-free application.