High response organic visible-blind ultraviolet detector

Abstract

The authors demonstrate a high efficiency visible-blind ultraviolet organic photodetector with a response of 30mA∕W. The active layer is a blend of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TPD) and tris(8-hydroxyquinoline) aluminum (Alq3). The authors show that the spontaneous as well as the electric field induced carrier generation efficiencies in the blend are enhanced over its constituents. The spontaneous carrier generation efficiency measured from total carrier collection measurements is 30% in the blend. The photoluminescence of the blend shows an efficient energy transfer from the TPD to Alq3 molecule. The mobility-lifetime (μτ) product in the blend is 2.2×10−12cm2∕V. The μτ product is weakly dependent on temperature.