The Studies On Optoelectronic Performances Of Organic Photovoltaic Diodes

In the field of organic optoelectric, organic photovoltaic (OPV) device draw much attention due to their promising cost, effectiveness and environmental benignity compared with inorganic ones. Currently, OPV device includes organic solar cell and organic photodetector deive. In this thesis, organic solar cell and organic ultraviolet photodetector device structure and their physics mechanisms were demonstrated detailedly.For OSC, some basic theories about organic photoelectric especelly on solar cell and photodetector were detailly introduced. Then, a cascade-energy-level alignment based organic PV cell was studied by stacking three materials with appropriate energy levels. This cell with a structure of ITO/m-MTDATA/CuPc/C60 /BCP/ LiF /Al was shown and it has an enhancement of power converson efficiency more than 30% over that of the standard reference cell (ITO/CuPc/C60/BCP/LiF/Al), which has only one exciton-dissociation interface. The efficiency improvement mainly ascribed to the ingenious cascade-energy-level alignment and the bipolar carrier transporting property.The high electron mobility and the proper energy level of CuPc was utilized to fabricated organic light emmiting diodes (OLED) and OSC, where CuPc acts as fonction of electron transporting layer/exciton blocking layer. The reasons for the high luminenscence efficiency in OLED and high open circuit voltage (Voc) in OSC were deeply researched, respectively. Besides the aforesaid two property of CuPc, we found the interaction between aluminium and CuPc play an important role in these two types of device.Two types of structural OPD devices, a planar heterojunction of layer-by-layer and a bulk heterojunction with a D/A blend layer was fabricated, respectively. Under UV-365 irradiation, the PHJ device offers a power conversion efficiency of ~10%, while the BHJ device behaves with a responsivity of 135 mA/W at 4 V bias. The BHJ device can also obtain a high exciplex electroluminescence (EL). The dependencie of PV and EL on exciplex formation has been discussed.Based on the third device, we demonstrated a very high voltage based organic photovoltaic diode by stacking two ultraviolet sensitized organic PV diodes in tandom way in the last part. It shows a Voc of 4.34 V under 365 nm UV irradiation with intensity of 2 mW/cm2. Due to the especially high Voc the PV diode device could be integrated with electronic logic device, as a result, a high or a low potential states can be harvested directly under the UV irradiation or not, respectively. The difference between high and low potential states is great and the temporal response is fast, which make it an attractive and promising candidate in application of optical encoder.