title: Triplet-to-singlet exciton formation in poly(p-phenylene-vinylene) light-emitting diodes.
abstract: The triplet to singlet exciton formation ratio in a MEH-PPV light-emitting diode is measured by comparing the triplet-induced absorptions with optical and electric excitations at the same singlet exciton density. The ratio is a strong universal decreasing function of the averaged electric field. Using 4 ns for singlet to triplet intersystem crossing time, the ratio is significantly larger than the spin-independent value 3 at intermediate field but is reduced to about 2 for higher field.
authors.affiliation: Institute of Physics, National Chiao Tung University, Hsinchu 300, Taiwan, Republic of China.
authors.forename: L C
authors.initials: LC
authors.lastname: Lin
authors.forename: H F
authors.initials: HF
authors.lastname: Meng
authors.forename: J T
authors.initials: JT
authors.lastname: Shy
authors.forename: S F
authors.initials: SF
authors.lastname: Horng
authors.forename: L S
authors.initials: LS
authors.lastname: Yu
authors.forename: C H
authors.initials: CH
authors.lastname: Chen
authors.forename: H H
authors.initials: HH
authors.lastname: Liaw
authors.forename: C C
authors.initials: CC
authors.lastname: Huang
authors.forename: K Y
authors.initials: KY
authors.lastname: Peng
authors.forename: S A
authors.initials: SA
authors.lastname: Chen