Organic Semiconductor Crystals Growth And Its Applications

Since the appearance of the first field-effect transistor based on the organic semiconductor material polythiophene in 1986,organic electronics has received continuous attention from many scientific researchers.Organic semiconductors have the advantages of light weight,low cost,solution processing,and excellent flexibility.And in the last few decades,the performance and stability of organic semiconductor materials have been greatly improved,and they are widely used in organic field effect transistors,organic light-emitting diodes,organic solar cells,and organic biosensors.The performance of organic electronic devices has a very close relationship with the structure of the crystal,and defects in the crystal structure will directly lead to the degradation of the device performance.The molecular arrangement of organic single crystal semiconductors is long-range and orderly,and the grain boundaries,traps and defect states are significantly reduced compared with polycrystalline and amorphous semiconductors.Therefore,it is an excellent material platform for the preparation of high-performance and high-stability organic electronic devices.Despite the above mentioned advantages,the application of organic single crystal semiconductors in high-performance array devices still faces challenges due to the difficulty in controlling the macroscopic orientation of crystal growth.In addition,although it has application advantages in many fields,when organic electronic devices achieve some specific functions,it will be difficult to meet actual application requirements due to problems such as low mobility or poor material stability.To solve this problem,it is necessary to construct new high-performance organic electronic devices based on new principles and new structures.The main innovative research results of this paper are:1.A new method of ultrasound assisted growth of highly directional organic semiconductor crystals is proposed.A fence-like shaped arrangement of crystals has been successfully grown on the substrate,and the length of the crystals can reach the millimeter level.Several control experiments have proved the important role of ultrasound for the directional growth of crystals,and at the same time explored the growth process of crystal growth.The crystal surface morphology and crystallinity were characterized by AFM,POM,XRD and GIXD,which proved that the grown crystals are high quality single crystal.Finally,through electrical tests,the average carrier mobility and maximum carrier mobility of the organic field-effect transistors prepared based on the above mentioned high-quality crystals are 3.0 cm² V^-1 s^-1 and 6.0 cm² V^-1 s^-1.2.An organic floating gate tunneling device biosensor with extended gate was processed.Using the extended gate electrode as a bioreceptor can prevent the test sample solution from directly contacting the organic semiconductor layer,which can avoid the damage of solution to the organic semiconductor crystal.In addition,the design combined with the structure of the floating gate device simplifies the structure of the sensor device,and the biological signal will directly affect the amount of charge in the floating gate layer of the floating gate device,which makes the changes of tunnelling threshold voltages and source/drain current.At present,preliminary experimental results have proved the feasibility of the sensor based on this structure.In the subsequent research work,we will continue to improve the material and structure of the device to increase the sensitivity of the sensor.