Related Experiment Videos
Triplet-to-singlet exciton formation in poly(p-phenylene-vinylene) light-emitting diodes
1Institute of Physics, National Chiao Tung University, Hsinchu 300, Taiwan, Republic of China.
Physical Review Letters
|February 7, 2003
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.