Recoverable Unstable Phenomena in PLED
聚合物发光二极管中可逆的不稳定行为

A recoverable negative resistance phenomenon and short\|term degradation in polymer light emitting diode (PLED) have been investigated in this paper. When the bias on the PLED is higher than a certain voltage, an abrupt change will take place in the current and luminance of PLED. It means that the current and luminance of PLED will increase accompanied by the decrease of its voltage. At the same time, the negative phenomenon will disappear gradually along with the increase of measurement times. We use a charge\|coupled device (CCD) pick\|up camera to take images of the abrupt change of luminance and find that the change of luminance corresponds to that of current. The short\|term degradations of luminance under different polar bias are also studied and the negative bias mode is proved to restrain the degradation of luminance effectively. We suspect that the reason for above recoverable but unstable phenomena relates to the defects in PLED and the filling behavior of carriers in it.