1Key Laboratory of Display Materials and Photoelectric Devices (Ministry of Education) and School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384 2Tianjin Key Lab for Photoelectric Materials and Devices, Tianjin 300384 3Biomolecular and Organic Electronics, Center of Organic Electronics, Department of Physics, Chemistry and Biology (IFM), Link?ping University, SE-581 83 Link?ping, Sweden
Abstract：We investigate the effects of ultraviolet (UV) irradiation treatment with varying irradiation intensities for different treatment times of poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film on the performance and stability of polymer solar cells (PSCs) based on regioregular poly(3-hexylthiophene) (P3HT) and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend. Ultraviolet-visible transmission spectra, x-ray photoelectron spectroscopy, contact angle measurement, atomic force microscopy and the Kelvin probe method are conducted to characterize the UV-treated PEDOT:PSS film. The results demonstrate that UV treatment can improve the power conversion efficiency (PCE) and stability of PSCs effectively. The best performance is achieved under 1200 μW/cm2 UV treatment for 50 min. Compared to the control device, the optimized device exhibits enhanced performance with a Voc of 0.59 V, Jsc of 12.3 mA/cm2, fill factor of 51%, and PCE of 3.64%, increased by 3.5%, 33%, 8.7% and 50%, respectively. The stability of the PSCs is enhanced by 2.5 times simply through the UV treatment on the PEDOT:PSS buffer layer. The improvement in the device performance and stability is attributed to the improvement in the wettability property and the increase in the work function of the PEDOT:PSS film by UV treatment, while the impact of UV treatment on the transparency of the PEDOT:PSS film is negligible. The strategy of using UV treatment to improve device performance and stability is attractive due to its simplicity, cost-effectiveness, and because it is suitable for large-scale commercial production.
2013, Vol. 30 
