Metal electrode effects on spin-orbital coupling and magnetoresistance in organic semiconductor devices

This letter reports the modifications of spin-orbital coupling and magnetoresistance of conjugated polymer upon deposition of metal electrode based on organic light-emitting diodes of poly[2-methoxy-5-(2(')-ethylhexyloxy)-1,4-phenylenevinylene]. We find that the reverse bias yields a largely increased magnetoresistance when the electron-hole capture zone is away from the metal electrode as compared to the forward bias with the electron-hole capture zone close to the metal electrode. The electroluminescence suggests that the deposited metal atoms enhance the spin-orbital coupling at the polymer/metal interface and consequently lead to electron-hole capture zone dependent magnetic field effects in organic semiconductor devices. (c) 2006 American Institute of Physics.