Iodine-doped pentacene schottky diodes for high-frequency RFID rectification

In recent years, there has been substantial interest in the development of printed RFID tags, primarily driven by the expectation of a substantial lowering in cost. Based on current standards, the most promising frequency for low-cost RFID is 13.56MHz. For low-cost RFID applications, the tags will be passive; i.e., these tags will operate on power supplied inductively by the reader. While the logic circuitry on the tag will operate only at approximately 200kHz, the rectification circuitry required to convert the harvested AC signal to DC will necessarily operate at 13.56Mhz. The antenna section in a 13.56MHz tag consists of an inductor+capacitor tank tuned to the frequency of operation. The signal is then rectified and filtered, producing a DC signal to power the RFID circuit. A high performance diode is one of the most likely candidates for this rectification. We have already demonstrated high quality printed capacitors and inductors [1]. Most recently, several groups have reported organic diode operation at 13.56MHz. However, to achieve this high frequency operation, the groups have used incident AC signals of >30V, which are only possible for extremely short range tag operation; to achieve operation in the 10cm range, it will be necessary to realize high frequency diodes capable of efficiently extracting power at 13.56MHz at lower incident voltages.