Effects of ligand structure on photovoltaic properties and charge transfer/recombination dynamics in PbS quantum dot heterojunction solar cells
作者单位：Nanjing Tech University The University of Electro-Communications Kyushu Institute of Technology
会议名称：《第三届新型太阳能电池学术研讨会》
会议日期：2016年
学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）]
关 键 词：Quantum dots Solar cells Surface ligands Charge dynamics
摘 要：Apart from the geometrical morphology of nanocrystals(NCs),the surface chemistry has also shown significant effects on the physical and chemical properties of *** quantum dots(QDs) are generally capped with long-chain,electrically insulating ligands which are introduced during the synthetic *** of these molecules with shorter chain ligands has been shown necessary to decrease the inter-dot spacing and improve the electron transfer in QD thin *** a number of ligands have been applied for the surface passivation of Pb S QDs,the effects of the surface ligand on the photovoltaic properties and exciton dynamics have not been fully understood in quantum dot solar cells(QDSCs).The impact of the ligand chain length and scaffold on the photovoltaic properties and exciton dynamics in Pb S QDSCs is investigated by ultrafast transient absorption(TA) spectroscopy,temperature-dependent photoluminescence(PL) and transient photovoltage decay measurements in this *** was observed the inter-dot spacing was narrowed in Pb S QD films as the decrease of ligand chain length,resulting the enhancement of exciton coupling and electron *** the shortest ligand thioglycolic acid(TGA) leads to the smallest inter-dot spacing,it does not give the highest photocurrent in QDSCs due to its acidity and ligand-induced defects on QD *** was found that 3-mercaptopropanoic acid(MPA) gave the highest photocurrent of 15.3 m A/cm and power conversion efficiency of 2.64%.Another interesting thing is that as the capping ligand on Pb S QDs was replaced by conducting conjugated molecules,the exciton coupling was enhanced but the fabricated solar cell was *** findings in this work are useful for the deeper understanding on the effect of surface ligands on QDs and would shed light on the further improvement of QDSCs.