Organic visible-blind ultraviolet photodetectors based on rare earth complex

Abstract

A new type of organic visible-blind ultraviolet (UV) photodetector based on tri(dibenzoylmethane)(4, 7-biphenyl-1,10-phenanthroline)europium (III) [Eu(DBM)3BPhen] as an electron donor and [6,6]-phenyl- C-61-butyric acid methyl ester ([60]PCBM) as an electron acceptor was fabricated. A peak response of 26 mA· W-1 and external quantum efficiency of 9.1% were obtained under illumination with 360 nm UV light at 2.1 mW·cm-2. This was because of the high UV absorption of Eu(DBM)3BPhen and the long lifetime, 300 μs, of Eu3+ ions, resulting in high exciton dissociation efficiency. Distinct photoluminescence quenching and photoconductivity of Eu(DBM)3BPhen were obtained by doping with [60]PCBM. A strong persistent photoconductivity was observed, which could be attributed to low charge carrier transportation and slow release of trapped exciton states in the blend films after the UV light is turned off. © Editorial office of Acta Physico-Chimica Sinica.