Photovoltaic properties of single and double layer structural organic thin film electroluminescent devices have been firstly reported.The polarity of photovoltaic indicated that the photovoltaic effect was Schottky effect.And different semiconductor contactsbetween different organic semiconductors or organic materials and electrodes of the devices have been given by analysing the action spectra of pbotocurrent of devices.In thesingle layer device(ITO/Alq

3

/Al)

the photocurrent was generated from Alq

3

/Al interface

which implied that there was a Schottky barrier here.For double layer device (ITO/diamine/Alq

3

/Al)

the photocurrent was generated from both Alq

3

/Al and diamine/Alq

3

interfaces.This comfirmed that a

p-n

junction exists at the interface of diamine/Alq

3

which had been assumed in prior paper.It is the

p-n

junction that confines the carriers and the excitons in a narrow luminessent layer and increases the EL efficiency and brightness in double layer device.Energy band models were proposed to explain the photovoltaic behaviors and the EL charactoristics of the devices.