Ultraviolet light detection using organic field-effect transistors

Abstract

In the present research functional organic thin-film transistors (OTFTs) were fabricated to achieve highly sensitive ultraviolet (UV) light detection Poly[2 5-bis(3-tetradecyl thiophen-2-yl)thieno[3 2-b]thiophene] (PBTTT) blended with poly(methyl methacrylate) (PMMA) at different weight ratio was adopted as the active layer of OTFTs After removing PMMA component a porous PBTTT active layer was formed Tris(8-hydroxyquinolinato) aluminum (Alq3) was deposited on the top of the PBTTT layer to serve as the UV light absorption layer Compared with the device without the Alq3 layer the UV light sensitivity of the devices with the Alq3 layer is increased greatly In addition the device made from PBTTT:PMMA of 9:1 shows the highest UV light sensitivity We observe that after the Alq3 layer absorbs UV light a highly efficient energy transfer from Alq3 to PBTTT can occur resulting in the greatly enhanced UV light sensitivity of the devices Moreover the devices can perform an electrical response to the weak UV light intensity of 1 μW/cm2 We successfully introduce a highly efficient UV light energy transfer layer to improve the function of OTFTs on UV light detection

Date of Award	2020
Original language	English
Supervisor	Wei-Yang Chou (Supervisor)