Study On Preparation And Device Performance Of Optical Amplifers Based On Organic Field-effect Transistors

Optoelectronic integrated devices based on organic field-effect transistors（OFETs）have developed rapidly in the past decade,including organic light-emitting transistors（OLETs）,and organic phototransistors（OPTs）,etc.At the same time,people have still explored new organic optoelectronic integrated devices based on OFETs.The combination of field-effect characteristics and optical amplification is expected to be applied in multi-functional products such as the Internet of Everything and organic laser television.Similar to the fabrication of other organic optoelectronic integrated devices,there are still many scientific and technical difficulties in realizing optical amplifiers based on the structure of OFETs.Among them,how to simultaneously accomplish the excellent electrical and optical properties is the most important step to promote the practical applications of these multifunctional devices.In this dissertation,by ingeniously introducing a polymer flexible distributed feedback（DFB）resonator into OFETs,the charge transport and optical amplification of the device were deeply investigated from the perspective of the active layer fabrication,the device structure,and the intrinsinc mechanism analysis.It is worth mentioning that the device integrates the characteristics of field-effect transistors and optical amplifiers,and overcomes the traditional problem of performance degradation of traditional integrated devices.The device configuration can realize the multi-functional integration of optoelectronics,which is beneficial for developing high-integration devices and electrically pumped lasers.The main findings of this paper include the following two points:（1）Two kinds of organic small molecule crystalline thin films,TIPS-pentacene and C8-BTBT,were prepared on the surface of PDMS dielectric layer by dip-coating,achieving OFETs devices with excellent performance.The effect of UVO treatments of PDMS surfaces on the molecular self-assembly was systematically explored.Subsequently,the optimal experimental conditions for depositing crystalline thin films were optimized,and the related mechanism was elaborated.The optimal experimental conditions for the two small molecules were as follows:In the case of TIPS-pentacene,acetone was selected as the solvent,the solution concentration was 0.8 mg/m L,the pulling speed was 10μm/s,and the OFET mobility was 0.0589 cm² V^-1 s^-1;As for C8-BTBT,dichloromethane was selected as the solvent,the solution concentration was 1.0 mg/m L,the pulling speed was 10μm/s,and the OFET mobility was 1.84 cm² V^-1 s^-1.This work provides an important experimental basis for the subsequent construction of optical amplifiersbased on OFETs with excellent optoelectronic properties.（2）Employing OFETs as the basic device structure,a DFB resonator as the dielectric layer was incorporated,constructing an organic field-effect optical amplifier.The influence of the active layer on the performance of organic optoelectronic integrated devices was systematically studied.Under this circumstance,device structures made from a single layer and stacked layers were employed,wherein the single-layer active layer is an organic laser material,and the stacked active layer is a combination of an organic high-mobility material and an organic laser material.Specifically,the effects of the preparation process of the active layer（spin coating and dip coating）and the types of mobility materials（organic small molecules and polymers）on the device performance were explored,respectively.The device based on TAT-3L as the active layer showed general electrical properties,but good laser output was obtained.The lasing threshold was only 4.93μJ/cm²with the half-peak width of 0.33 nm and the lasing wavelength output of about 486 nm.This research provides an important platform for the preparation of OFET-based optical amplifiers with excellent optoelectronic properties,which is advantageous for promoting the development of multifunctional organic optoelectronic integrated devices.