Positive Magnetic Effect of Photo-Enhanced Current in anthracene. A Novel Determination of Triplet Triplet annihilation Rate Constant

Abstract It has been observed that under certain conditions (light intensity, field strength, etc.) the photoenhanced current (PEC) increases on applicationof external magnetic fields. This anomalous positive magnetic effect is accounted for in terms of a competition betweeen triplet-triplet and triplet-doubled reactions. Numerical simulation shows that the observed anomaly is possible for a rather limited range of parameter values. Hence, the analysis of the effect offers a good chance to check the magnitude of the triplet-triplet annihilation rate constant γTT. The currently accepted value of γTT = 2 × 10−11 cm3 s−1 is confirmed.