Solution Preparation Of High Performance Organic And Organic Composite Phototransistors

Light detection and imaging devices have attracted much attention in fields such as communication,pollution monitoring,astronomical study and health care.Phototransistor,with three terminal structure which can reduce noice and amplify signal,is a promising photodetecting device structure.Using highly ordered organic single crystal and organic-inorganic hybrid perovskite as active materials of field-effect transistors is a feasible way of improving carrier mobility,thus,it is meaningful for achieving high performance phototransistors.Solution way is the most common way of fabricating low cost,large scale organic phototransistors.However,organic single crystal phototransistors are still barely reported by now.The main drawback of organic-inorganic hybride perovskite phototransistors remains in the high dark current and the resulting low signal-to-noise ratio due to the use of high conducting material combined with 3D structured perovskite,which is not ideal for the 2D carrier transpot mode of field-effect transistors.Thus,a high performance perovskite phototransistor remains to be achieved.In this thesis,we use organic semiconductor single crystals and organic-inorganic hybride perovskite as active material to fabricate high performance phototransistors.1.We report the high quality C8-BTBT single crystal ribbon developed in a solution way used as channel layer of FETs,with hole mobility of 0.89-1.57 cm² V^-1 s^-1.Under visible-blind?365 nm?and deep?280 nm?UV signals,both the light-to-dark current ratio?3.0×104?and responsivity(1200 A W^-1)are of the best in organic UV detectors.2.A solution prepared 2D layered hybride perovskite was used as channel layer of FETs and achieved a mobility of 0.76?1.2 cm² V^-1 s^-1.This device achieved ultrahigh detecting performance under very week visible light.Both the light-to-dark current ratio?8000?and responsivity(1.9 × 104 A W^-1)reached to the best among perovskite phototransistors.