After some less balanced injection of charge carriers, we observe violet-blue electroluminescence beyond 6 V and 9 V with CIE color coordinates around x = 0.159 and y = 0.035 for PyPhCz and x = 0.157 and y = 0.038 for PyFlCz, which is in the blueviolet spectrum (see Figure ). The electroluminescence spectra are almost identical to the fluorescence in nonpolar solvents (cf. Figure and). Upon closer inspection of the J-V curve, there is a small change in the slopes at 7 V and 10 V, which might be an effect of traps that may also have contributed to the charge imbalance at lower voltages and now become depopulated at such increased voltages (see Figure ). Altogether, both OLEDs are stable over the interval of the applied voltages and we obtain a maximum EQE of 7.13 % for PyPhCz and 6.06 % for PyFlCz (see Figure ). From these EQEs, we can determine the spin factors ηST and provide further evidence for the triplet contribution, using the following equation: