Mats Fahlman：Organic heterojunctions in binary and ternary organic solar cells
讲座题目：Organic heterojunctions in binary and ternary organic solar cells
Prof. Mats Fahlman received his MSc inEngineering Physics (1991) and PhD in Surface Physics and Chemistry (1995) fromLinkoping University. He currently holds an endowed chair in Surface Physicsand Chemistry at the Laboratory of Organic Electronics, Linköping University. Heis active in the research of organic semiconductors with over 200 publications,using primarily surface science techniques to explore materials and interfacesas well as their effect on device properties. Prof. Fahlman is also active insynchrotron radiation research, currently serving as a member of the ScientificAdvisory Committee of MAX IV and was prior a member of the Board of Directorsfor ten years. He is the recipient of the European Union Descartes Prize andthe Göran Gustafsson Prize in Physics.
Matched energy level alignment is a key requirement for efficientorganic devices such as organic light-emitting diodes, photovoltaics, andtransistors.1 In organic solar cells (OSCs), the organic-organicheterojunctions are of special importance as they effect both charge generation2and open circuit voltage,3 and by tuning them in binary3and ternary devices,4 an optimized performance can be obtained. Thermal annealing and additives are otherapproaches that are widely used to optimize the performance of OSCs asdiscussed in a recent review,5 and thermal annealing/stress is alsonecessary and unavoidable in large scale production of OSCs. Large efforts havebeen devoted to reveal the effect of the thermalannealing on morphology and tounderstand the correlation between change in morphology and device propertiesof OSCs in both fullerene and non-fullerene based OSCs.6,7 The effectof thermal stress/annealing on energy level alignment and related properties ofthe devices are less discussed, however, compared tothe extensively explored effect on morphology and corresponding deviceperformance. Here we discuss energy level alignment at heterojunctions in OSC,their effect on device performance and use all polymer solar cells todemonstrate thermal annealing effect on energy level alignment and thecorresponding effect on the device properties.7