Accessing MHz Operation at 2 V with Field‐Effect Transistors Based on Printed Polymers on Plastic

Abstract

Organic printed electronics are suitable for the development of wearable, lightweight, distributed applications in combination with cost‐effective production processes. Nonetheless, some necessary features for several envisioned disruptive mass‐produced products are still lacking: among these radio‐frequency (RF) communication capability, which requires high operational speed combined with low supply voltage in electronic devices processed on cheap plastic foils. Here, it is demonstrated that high‐frequency, low‐voltage, polymer field‐effect transistors can be fabricated on plastic with the sole use of a combination of scalable printing and digital laser‐based techniques. These devices reach an operational frequency in excess of 1 MHz at the challengingly low bias voltage of 2 V, and exceed 14 MHz operation at 7 V. In addition, when integrated into a rectifying circuit, they can provide a DC voltage at an input frequency of 13.56 MHz, opening the way for the implementation of RF devices and tags with cost‐effective production processes.

Sub‐3 V ZnO Electrolyte‐Gated Transistors and Circuits with Screen‐Printed and Photo‐Crosslinked Ion Gel Gate Dielectrics: New Routes to Improved Performance

“…The responses at different V D and V Bias values are plotted in Figure c,d. The maximum observed oscillation frequency, f osc , is 1.9 kHz with V D = 3 V and V Bias = 2.75 V . Considering the five‐stage ring oscillator rule, the stage delay is 50 μs, which is consistent with the data obtained from the discrete inverter dynamic response.…”

Organic thin-film transistors with flame-annealed contacts

“…The reliability factors for these two devices are both 0.93 (a reliability factor of 1 corresponds to an ideal device) [30]. This reliability factor implies that, even if bad contacts were present, the true mobility of the devices is within 7% of the measured value, and 0.93 is on par with or betters values reported for other systems [31][32][33], with the exception of single crystals [30]. Measurements on a large set of devices (over 100) resulted in a lower average threshold voltage in the flame annealed OFETs, Vth = 2.7 V ± 1.2 V, compared to Vth = 6.2 V ± 1.2 V in the control, suggesting a lower density of traps in these samples.…”

Walking the Route to GHz Solution‐Processed Organic Electronics: A HEROIC Exploration

“…The bias voltage, instead, cannot represent a mean for achieving high‐frequency operation, but should be considered as a specification defined by the target application: while some use‐cases allow for high supply voltage, the majority of portable, stand‐alone devices require the compatibility with thin‐film power sources or energy harvesters. Following such considerations, some authors have recently reported the voltage‐normalized transition frequency f t / V alongside with the simple f t . Since it encompasses the OFET speed performance only in terms of geometrical and physical parameters, f t / V can be considered as a more convenient mean for the comparison of different technologies.…”

“…This limitation is related to the parasitism introduced by the characterization setup itself and, only in few cases, the measurement bandwidth was extended to few tens of MHz by adopting inductive probes. Consequently, f t of the most performing OFETs to date was often determined via extrapolation from the data obtained at low frequency, where parasitism is negligible or can be easily accounted for . In the few cases in which inductive probes were used, f t values around 20 MHz have been measured without extrapolation.…”

“…We summarize in Table 1 a selection of the best results reported in the literature for organic transistors and circuits, in terms of f t or τ p , while data for f max are generally not available in the literature of OFETs. In our summary, we not only try to select the best achieved results in the literature, but we also aim at emphasizing some selected features of interest for the future applicability of organic electronics to real‐life examples and its ease of scalability to industrial manufacturing.…”