Source-gated transistors (SGTs) are emerging devices enabling high-gain single-stage amplifiers with low complexity. To date, the p-type printed organic SGT (OSGT) has been developed and showed high gain and low power consumption. However, complementary OSGT circuits remained impossible because of the lack of n-type OSGTs. Here, we show the first n-type OSGTs, which are printed and have a high intrinsic gain over 40. A Schottky source contact is intentionally formed between an n-type organic semiconductor, poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (N2200), and the silver electrode. In addition, a blocking layer at the edge of the source electrode plays an important role to improve the saturation characteristics and increase the intrinsic gain. Such n-type printed OSGTs and complementary circuits based on them are promising for flexible and wearable electronic devices such as for physiological and biochemical health monitoring.

of over 4 cm 2 V −1 s −1 and high deposition speed of 2.4 m min −1 , depending on the type of printing method. [4] In addition, the precise selection of organic solvents such as anisole and 3-methylcyclohexanone may enable devices to be fabricated with less environmental impact than conventional methods. [5] Therefore, devices fabricated by the printing process will be an important factor in realizing a sustainable development goals (SDGs) in the future. [6] The unique and outstanding characteristics of printed OTFTs have led to their application in amplifiers for flexible and wearable sensor devices. [7] It has been believed that reducing the energy barrier at source and drain electrodes is important for improving the circuit performances. [8] So far, many circuit applications of OTFTs that exhibit good charge injection have been reported. However, obtaining high enough gain usually requires multistage OTFT amplifiers, which increase the complexity, circuit size, and fabrication cost. Reducing power consumption is also important for wearable devices with a small power source.Source-gated transistor (SGT) was first demonstrated with amorphous silicon by Shannon and Gerstner in 2003. [9] SGT utilizes a Schottky barrier at source electrode and controls the current by gating the barrier instead of gating the channel region. [10] Although the maximum current is decreased by the introduction of the Schottky barrier, SGT has advantages in high gain and small device variability. The high gain originates from the high-output resistance in saturation regime. Because of the pinch off near the source electrode instead of the drain electrode, SGT exhibits an excellent saturation behavior. SGT performance is less sensitive to the channel length because the current is controlled by the electrode but not the channel. This is important in printed electronics, where the geometry variation is significant. A phenomenon similar to SGT with organic semiconductors was first reported with a numerical simulation by Rapisarda and co-workers in 2013. [11] Then, Nathan and co-workers applied the printed organic SGT (OSGT) to multistage amplifier circuits with p-type organic semiconductor C8-BTBT in 2019. [12] The OSGT exhibited several superior performances such as high gain of 260 V/V, steep subthreshold slope (60 mV dec −1 ), and small device variability. The first n-type OSGT using N2200 as an organic semiconductor was reported in 2022. [13] Although SGT has such a high potential, [14] it has been also known that the saturation behavior can be severely deteriorated Printed amplifiers are promising components for flexible and wearable devices. The circuits need to have small footprint, high amplification, and low power consumption, which is not simultaneously possible with conventional thin-film transistors because multiple stages are required and introduce sources of variability, failure, or wasted area. Source-gated transistors (SGTs) can in principle have extremely high intrinsic gain but this is not always the case because of latera...