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Research Of Organic Thin Film Transistors Based On In Situ Annealing Treatment

Posted on:2019-06-21Degree:MasterType:Thesis
Country:ChinaCandidate:F Q YangFull Text:PDF
GTID:2348330569495506Subject:Engineering
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Organic thin film transistor(OTFT)is a kind of field-effect devices composed of deposited organic semiconductor.The research of OTFT is being aggressively pursued primarily because of its potential for low cost,light weight,mechanical flexibility and low temperature fabrication of large area circuits.OTFT is extremely useful in multi-dimensional applications such as flexible integrated circuits,sensors,organic memory,e-paper and radio frequency identification tags.After 30 years of research of OTFT,the electrical properties and stability of organic thin film transistors have improved a lot.However,the commercialization of OTFT,faces several realistic obstacles,such as cumbersome preparation process and low production efficiency.Thus,further exploration of fast and high efficient fabrication methods has attracted people's attention.In this work,the in situ annealing treatment based on spray-coating,was proposed to fabricate organic films of OTFTs.This process was better than traditional post-annealing methods,which was attributed to improve surface morphology and crystallization of Tips-pentacene.And high-performance OTFT and OTFT gas sensors were fabricated.Specific contents are shown as follows:1.The effect of in situ annealing process on electrical performance of OTFT was investigated.Different from traditional post-annealing process,spray-coating and annealing process were executed at the same time during the in situ annealing treatment,and the annealing temperature had a big influence on electrical performance.Compared to the control device,device performance with the 60°C in situ annealing treatment exhibited the highest hole mobility of 0.19 cm~2/Vs,which was almost 3.5 folds of control one.The enhanced performance was attributed to the improved surface morphology and crystallization of Tips-pentacene,which resulted form the controlled evaporation rate of residual solvent with proper in situ annealing temperature.In addition,compared with the post-annealing process,the in situ annealing process saves the annealing time,improves the film preparation efficiency,and helps reduce the time costs in industrial production.2.The effect of in situ annealing process on sensing performance of OTFT gas sensor was investigated.The OTFT gas sensor using the same spray process was fabricated,and the gas sensing characteristics of the OTFT gas sensor was studied.The results showed that devices with in situ annealing treatment shown better response speed and response rate,and the response rate increased with the in situ annealing temperature.The OTFT gas sensor with the 120°C in situ annealing treatment exhibited a good level of response rate of 138%and an ultralow detect limitation of 1 ppm.Meanwhile,the morphology of the dielectric layer and the crystalline state of the active layer were studied by means of atomic force microscopy(AFM).The AFM results indicated that the performance enhancement was mainly attributed to the smaller crystal grain,large surface area and more charge traps.In summary,the effect of in situ annealing process with spray-coating on electrical and sensing performance of OTFT and OTFT gas sensor were investigated Systematically,which laid a foundation for the industrial production of high performance OTFT and OTFT gas sensor.
Keywords/Search Tags:organic thin film transistor (OTFT), in situ annealing, spray-coating, gas sensor, Tips-pentacene
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