Otro
Observation of persistent photoconductivity in vanadyl phthalocyanine
Registro en:
Journal of Physics D-applied Physics. Bristol: Iop Publishing Ltd, v. 41, n. 12, p. 7, 2008.
0022-3727
10.1088/0022-3727/41/12/125107
WOS:000256568000018
Autor
Santos, L. F.
Faria, R. M.
Del Cano, T.
de Saja, J. A.
Constantino, C. J. L.
Amorim, C. A.
Mergulhao, S.
Resumen
Persistent photoconductivity (PPC) in vanadyl phthalocyanine (VOPc) organic light-emitting diodes was investigated using photoconductive time response, photocurrent-voltage characteristics and charge extraction in linearly increasing voltage (CELIV) measurements. The experiments were performed in phase 1 (amorphous) and in phase 2 (crystalline) samples obtained by the physical vapour deposition (PVD) technique over ITO/glass electrodes with an Al covering electrode. The results indicated a photoconductivity with a long decay time in phase 1 VOPc described by a stretched exponential relaxation. The device showed a rectifying behaviour and the mobility of holes was measured by CELIV, following a dispersive model. In crystalline samples the PPC effect was not observed and the dominant mechanism of transport of holes was hopping in a Gaussian density of states.