Dr Ruiyao Wang (Department of Chemistry at XJTLU)
Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic cells. Inverted planar perovskite(PVSK) solar cells with a device structure of ITO / PEDOT : PSS / PVSK / PCBM / Al have emerged as a new generation solar cell owing to their advantages, such as ease of fabrication, low processing temperature and good compatibility with roll to roll processing. Solvent engineering has been proved to be a very effective way to enhance the performance of the solar cells by improving the coverage, the thickness and the morphology of the perovskite films. Here we report the effects of the mixed solvents of N, N-dimethylformamide (DMF) and -butyrolactone (GBL) on the performance of the solar cells with a device structure of ITO / PEDOT : PSS / CH3NH3PbI3-xClx / PCBM / Al . For example, when the pure GBL was used the solvent, the devices gave an average PCE 9.63% (Voc = 0.94 V, FF = 0.69, Jsc (calcd) = 13.89 mA/cm2), while with the mixed solvent (GBL:DMF = 3:1(v/v)), the average PCE became 11.94% (Voc = 0.88 V, FF = 0.69, Jsc (calcd) = 19.28 mA/cm2), an increase of 19.4%. The perovskite films from the different solvents were characterized by UV-Vis, XRD and SEM.