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Electrical annealing (EA) is one of the post treatments to enhance the electrical performances of organic devices. To date, the improvements using EA have only been reported for the solution-processed devices because its mechanism has been known as the alignments of ionic impurities or polymer chains. In this paper, we applied EA to thermally evaporated organic diodes which not have ionic impurities or polymer chains. After EA, the turn-on voltage of the diode was reduced, and the forward-bias current of the diode was increased without changing the reverse-bias current, resulting in an improvement of the cutoff frequency of the rectifier. In addition, we proposed a new mechanism to explain why the EA can be applied to the thermally evaporated organic devices. Based on time-of-flight secondary ion mass spectrometry and impedance spectra, we suggest that this improvement is due to the creation of a MoO3:pentacene mixed layer, leading to ease of charge injection. We believe that our finding will be helpful to understand change at the organic/metal interfaces and useful to apply a wide range of organic devices such as organic photovoltaics, organic light-emitting diodes, and organic thin-film transistors.

This study shows that, at the present state of development, one-bit frequency doubling tags seems to be feasible exploiting green technologies. The optimal process will exploit a paper substrate where both antennas and pentacene organic diodes could be deposited by means of ink-jet printing. The proposed frequency doubling tag has a fully uniplanar layout (no vias needed), whereas the use of simple non-linear devices is adequate to open the market of organic microwave RFID systems.