Reconfigurable Multifunctional Ambipolar Polymer‐Blend Transistors with Improved Switching‐Off Capability

Abstract

Ambipolar field‐effect transistors allowing both holes and electrons transport can work in different states, which are attractive for simplifying the manufacture of circuits and endowing the circuits with reconfigurable multi‐functionalities. However, conventional ambipolar transistors intrinsically suffer from poor switching‐off capability because the gate electrode is not able to simultaneously deplete holes and electrons across the entire transport channel, which hurdles the practical applications. This study shows that the switching‐off capability of polymer ambipolar transistor is significantly improved by up to three orders by introducing non‐uniformly distributed compensation potentials along the channel to synchronically tune the charge transport at different channel locations. The non‐uniform compensation potential is experimentally generated by the non‐uniformly distributed electret charges, which are pre‐injected into the insulators from source and drain electrodes. By this method, both n‐type and p‐type operations with high mobility (2.2 and 0.8 cm2s−1V−1 respectively) and high on/off ratio (105) are obtained in the same device, and the different states are reversibly switchable. Moreover, this method endows the device with diverse device characteristics and reconfigurable multi‐functionalities, which promotes the application of ambipolar transistors in complementary metal‐oxide semiconductors‐like circuits and some emerging electronics, including reconfigurable devices, multi‐level memories, and artificial synapses.

Improving Charge Injection at Gold/Conjugated Polymer Contacts by Polymer Insulator‐Assisted Annealing for Transistors

“…It can be anticipated that the amorphous PS dilutes the conjugated polymer DPP-DTT, so that the conjugated polymer only crystallizes locally and does not form a long-range crystalline structure in the blend film. [33,[43][44][45] However, the absorption peaks of DPP-DTT red-shift for a few nanometers and the intensity of 0-0 vibrational transition peak increases after blending with PS (Figure 3e), and the blend film with 10% DPP-DTT shows the largest ratio of 0-0/0-1 peaks as compared to other blend films (Figure S12a, Supporting Information). The increased 0-0/0-1 ratio and the red-shift of absorption peaks indicate the aggregation of DPP-DTT is enhanced in the blend film, possibly due to the confinement effect of PS in the film formation process.…”

Rapid Charge Storage and Release at Etching‐Assist Electret in Organic Transistors for Memories, Photodetectors, and Artificial Synapses

“…When two successive negative gate voltage pulses are applied, the current after the second pulse is smaller than the current after the first pulse (Figure S17c, Supporting Information). [ 8,46,69 ] The changes of inhibitory postsynaptic current after stimulation with different numbers of negative gate pulses are shown in Figure 6e, IPSC stimulated by 50 consecutive pulses was much lower compared to that under two consecutive pulses, which is similar to short‐term depression (STD) transfer to long‐term depression (LTD). The synaptic performance of the device with unetched PS is shown in Figure S18, Supporting Information.…”

“…[ 9 ] PPF and PPD are defined as the synaptic current after the second pulse increasing or decreasing compared to the first pulse, and the index is defined as PPF/PPD = (A2 – A1)/A1 × 100%, where A1 and A2 are the peak values of postsynaptic current induced by the first and the second pulse, respectively. [ 69–70 ] PPF index extracted from the results in Figure S17a, Supporting Information, is shown in the inset of Figure 6c, which decays exponentially with increasing pulse interval. For the plasma‐treated device, the changes in postsynaptic current after stimulation with different numbers of gate pulses are shown in Figure 6d.…”

Side-Chain Engineering of Polystyrene Dielectrics Toward High-Performance Photon Memories and Artificial Synapses

“…STM could be transferred into LTM with repeated light spike stimulations, which is analogous to the learning process of the human brain. 30,55 In Figure 5f, STM is formed after 10 and 30 spike stimulation, while LTM with greatly enhanced EPSC is achieved after 50 spikes. It is to be noted that even though LTM can be achieved after 50 times of learning (stimulation) for all o-FPS, m-FPS, and p-FPS devices, a huge difference exists among the intensity of these memories, which is indicated by the amplitude of EPSC.…”