Study On The Effect Of Interfacial Modification And Device Structures For Organic Solar Cells

Organic Photovoltaics（OPVs） have drawn growing attention and become a research focus in the field of renewable energy source due to its superiorities of solid-state, flexible, large-area and low-cost. In the structure of OPV, the interface between the active layer and the electrode directly determines the efficiency and stability of the OPV device. Therefore, interfacial modification plays a dominant role in improving the performance of orgaic solar cells. Through selected the appropriate materials of interface modification, improved process engineering and device structures that can improve the performance of organic solar cell device. The main research contents include three parts as follows:（1） UV treatment based on P3HT:PCBM orgain solar cell performance impactBefore the active layer thermal annealing, use the UV light in the inert gas environment to deal with active layer. Aggregation size of the active layer is observed to increase after UV irradiation, according to the transmission electron microscopy images. Characterization of X-ray diffraction and atomic force microscopy demonstrate that UV irradiation can improve the crystallinity of P3 HT phase and optimize the roughness of the active layer. Simulation results indicate UV irradiation of appropriate time can improve physics parameters of the devices. As a result, the maximum power conversion efficiency of the devices is increased from 3.5% to 4.5%.（2） MoO₃ as anode interface modification material effect on the small molecule OPVThrough the analysis of the active layer surface morphology, the external quantum efficiency and preparation of OPV device performance testing, finds that the open-circuit voltage and fill factor of OPV devices with MoO₃ are higher than the ones which use PEDOT: PSS. And atomic force microscope images show that the active layer which is prepared on the MoO₃ layer is smoother than the ones prepared on the PEDOT:PSS. And device performance has better upgrade, in particular to improve the energy conversion efficiency of OPV devices.（3） The influence of device structure for small molecule OPV’s properties based on DIP:C60Study the performance difference between two different device structures of small organic molecules. The performance of the doped OPV device preferred, and its energy conversion efficiency is nearly 43% higher than the flat structure OPV device’s. On this basis, using BPhen and Alq₃ as cathode buffer layer prepares the OPV devices which structure is flat and doped structure OPV devices. For the flat devices, the energy conversion efficiency of the OPV devices which use Alq₃ than the OPV devices with BPhen is nearly 24% higher. But for the doped devices, using BPhen as cathode buffer layer for the promotion effect of the device performance is better than the ones with Alq₃.