Low-cost fabrication of organic rectifying diodes for high-speed AC/DC conversion

Toward the establishment of low-cost manufacturing, ohmic contact formation techniques of organic devices should be developed without use of noble metals. In this study, organic diodes based on poly(3-hexylthiophene-2,5-diyl) (P3HT) were fabricated on FTO/glass substrates using non-noble metal (Al) anode electrodes and exhibited rectification behavior when depositing MoO_x beneath the Al anode electrode. This suggests that an ohmic-like contact was selectively obtained due to the conduction path formed between the Fermi level of Al and charge-transfer state of P3HT. High-speed AC/DC conversion efficiency of P3HT-based rectifying diodes was investigated using a half-wave rectification circuit and compared to a commercially-available Si Schottky diode. Reduction in the rectifying characteristics of the half-wave rectification circuit using the P3HT devices with increasing the measurement frequency was discussed on the basis of equivalent circuit model.