Ultra-wide bandgap organic acceptor material and its application in organic UV photodetector

• DOI: 10.1016/j.synthmet.2016.05.004
• Publication Date: 2016-05-20T02:45:03Z
• Authors: Weiwei Tu; Tang Liu; Zhongqiang Zhang; Gang Wu; Hongzheng Chen; Mang Wang
• Keywords: Diphenylphosphine oxide; Ultraviolet; Triphenylamine; Acceptor; Thermal Stability; Photocurrent; Electron acceptor

Abstract Two fluorene derivatives, 2-(1,1′:3′,1″-triphenyl-5′-yl)-9,9-diphenyl-9H-fluorene (TPF) and (9,9-diphenyl-9H-fluoren-2-yl)diphenylphosphine oxide (DFPPO) with wide bandgap and good thermal stability were synthesized. The electron mobility of DFPPO is 5 times higher than that of TPF because of the introduction of the electron-withdrawing diphenylphosphine oxide group. The planar heterojunction organic ultraviolet photodetectors (UVDs) were fabricated by applying TPF or DFPPO as electron acceptor, 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) as donor. The UVDs with structure of ITO/PEDOT:PSS/C8-BTBT/DFPPO/LiF/Al presented higher ultraviolet response compared to the TPF based counterpart. Corresponding dark to light current ratio and higher sensitivity is about 179 and 0.69 mA/W under illumination of 1 mW/cm 2 365 nm UV light and bias of −0.5 V.