Comparison of transient state and steady state exciton-exciton annihilation rates based on Förster-type energy transfer

We investigated differences between the transient state and steady state exciton–exciton annihilation rates based on Forster-type energy transfer. The exciton–exciton annihilation rate of an organic semiconductor is usually determined by transient state photoluminescence measurements using a pulsed laser or steady state photoluminescence measurements using a continuous wave laser. However, it is unclear that the respective annihilation rates determined by their rate equations are the same. In calculations with platinum-octaethylporphyrin (PtOEP) parameters, Monte Carlo simulations gave two different annihilation rates for the transient state and the steady state. The analytical models based on Forster-type energy transfer also showed the same result. These results indicate that the exciton–exciton annihilation rates in transient state and steady state are distinguished.