Effect Of Interfacial Layer On The Performance And Stability Of Polymer Photovoltaic Cells

Organic solar cells have generated a lot of interest for application as a renewable, non-conservative, and clean source of energy. Significant effort has been made toward improving the performance and stability of organic solar cells. Works on the cell structure modification and insertion of a buffer layer between electrode and the active layer have been proveded to be an effective way to improve the performance and stability. The main objective of this work is to study the effect of interfacial layer on the performance and stability of polymer photovoltaic cells. which carried in two aspects mainly:1. Polymer solar cells by using poly(ethylene oxide) as cathode interfacial layerThe effect of poly(ethylene-oxide) (PEO) as a cathode interfacial layer on the performance and stability of polymer photovoltaic cells based on regioregular poly(3-hexylthiophene) (P3HT) and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend was carried out. The effect of the PEO layer's thickness on the performance was investigated. The results indicated that the power conversion efficiency (PCE) of the device with PEO (1000rpm) interfacial layer is 3.36%, and then decreased to 20% of the initial value after 90 hours. Compared with the control device (PCE is 1.92%, decreased to 5% of the initial value after 90 hours), the PCE of the device with PEO interfacial layer increased by 75% and the stability extended 3 times.2. Polymer solar cells with ultraviolet-ozone treated PEDOT:PSSThe effect of ultraviolet (UV) irradiation treatment of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) films on the performance and stability of polymer solar cells based on regioregular poly(3-hexylthiophene) (P3HT) and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend was investigated. The effect of UV irradiation intensity and treatment times on the performance were also investigated. X-ray photoelectron spectroscopy (XPS) and contact angle measurement were conducted to characterize the UV-treated PEDOT:PSS films. It was found that the power conversion efficiency (PCE) increased from 2.43% to 3.64%, and the stability enhanced 2.5 times after UV irradiation treatment. The enhancement in the PCE and stability is attributed to the improvement of wettability property and the change in work function of the PEDOT:PSS films after UV irradiations. The optimized irradiation intensity is 1200uW/cm2.