Quantum efficiency harmonic analysis of exciton annihilation in organic light emitting diodes

摘要: Various exciton annihilation processes are known to impact the efficiency roll-off of organic light emitting diodes (OLEDs); however, isolating and quantifying their contribution in presence other factors such as changing charge balance continue be a challenge for routine device characterization. Here, we analyze OLED electroluminescence resulting from sinusoidal dither superimposed on bias show that nonlinearity between recombination current output arising mixes quantum measured at different harmonics manner depends uniquely type magnitude process. We derive series analytical relations involving DC first harmonic external enable rates quantified through linear regression independent evaluate them prototypical fluorescent phosphorescent OLEDs based emitters 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran platinum octaethylporphyrin, respectively. go that, most cases, it is sufficient calculate needed directly derivatives versus curve, thus enabling this analysis conducted solely standard light-current-voltage measurement data.