Abstract
Magnetoconductance response (MC) in illuminated tris-(8-hydroxyquinolinato) aluminum (Alq(3)) single layer has been studied to clarify the role of excitons and electron-hole (e-h) pairs on the MC generation. By fitting the MC curves at different bias conditions, the contribution of e-h pairs and excitons to the MC can be differentiated in the same material. The fitting results indicated that hyperfine mixing between the singlet and triplet e-h pairs results in a Lorentzian type MC within hyperfine field and charge reaction of triplet excitons induces a high-field MC following a non-Lorentzian shape, respectively. Moreover, the characteristic field width for the high-field MC is very different at forward and reverse bias regime, implying that the rate strength for the hole/electron-exciton reactions in Alq3 should be treated separately. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4795937]