Study On Multifunctional Organic Transistor Memory Based On PTB7-Th

Organic field-effect transistors possessing functions of both memory and photoelectric synaptic transistor have potential applications in brain-like optoelectronic computing.However,one single semiconductor layer can’t absorb enough photons to ensure reliable memory performance and synaptic simulation,and the preparation of multilayer structures is complicated,which restrict its practical applications.In this paper,photo-responsive organic material PTB7-Th and PS were mixed and then spin-coated to prepare organic field-effect transistor based on pentacene.On the basis of a good memory performance,STP,LTP and SRDP characteristics of artificial synapse were simulated.Besides,organic field-effect transistors based on one-step spin-coating of TIPS-pentacene and PTB7-Th achieved similar memory performance and lower operating voltage(5 V)of photo-electric synaptic device with a simplified fabrication.They further simulated optical sensing functions at negative gate bias(-20 V).This paper produced reliable field effect transistors with the potential application of brain-like optoelectronic system through a simple process.The main research results are as follows:1.A mixture of PTB7-Th and PS was spin-coated for fabricating organic field-effect transistors with pentacene.The device with a mixture ratio of 1:1 could obtain a memory window of nearly 20V under the synergy of a white light illumination of 5 m W/cm~2 and a gate bias of 20 V for 1 s.Besides,the memories presented a long data retention time of 10,000 s within the retention test and a stable on/off current switching behavior over 100 cycles during ERPR cycling test.Transistors prepared in this work also simulated the characteristics of artificial synaptic under the gate bias of 20 V and 5m W/cm~2 white light and showed a good EPSC response to 420 nm blue violet light.The use of PTB7-Th improves the photon absorption efficiency,thus on the basis of stable memory performance of the device based on the single pentacene layer,the artificial synapse was further simulated reliably.2.A one-step spin coating of TIPS-pentacene and PTB7-Th was used to fabricate FET.The phase separation has been qualitatively demonstrated through atomic force microscopy and scanning electron microscopy.Transistors based on the TIP-Pentacene/PTB7-Th hybrid film with a mixing volume ratio of 1:3 achieved stable memory performance with a simplified fabrication.The effectively carrier transport between the two layers vertically separated facilitated that the characteristics of the artificial synapses could be simulated at a low operating voltage of 5 V.The device exhibited tunable synaptic properties at different wavelengths(420 nm/670 nm).Besides,the optical sensing function and photoelectric synaptic function could be switched by changing the polarity of the grid bias.Compared to the first work,a simplified fabrication,a low operating voltage and simulation of optical function were achieved at the same time.