This study reveals that the interaction between a 2D material and its substrate can significantly modify its electronic and optical properties, and thus can be used as a means to optimize these properties. High-temper...This study reveals that the interaction between a 2D material and its substrate can significantly modify its electronic and optical properties, and thus can be used as a means to optimize these properties. High-temperature （25-500℃） optical spectroscopy, which combines Raman and photoluminescence spectroscopies, is highly effective for investigating the interaction and material properties that are not accessible at the commonly used cryogenic temperature （e.g., a thermal activation process with an activation of a major fraction of the bandgap）. This study investigates a set of monolayer WS2 films, either directly grown on sapphire and SiO2 substrates by CVD or transferred onto SiO2 substrate. The coupling with the substrate is shown to depend on the substrate type, the material- substrate bonding （even for the same substrate）, and the excitation wavelength. The inherent difference in the states of strain between the as-grown and the transferred films has a significant impact on the material properties.展开更多
Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve ...Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve the performance of organic solar cells(OSCs).Contrary to conventional understanding,this research proposes a new strategy for ternary OSCs implicating that"weakly crystalline materials can also optimize the morphology of the active layer and improve the OSCs performance".Herein,we designed and synthesized two liquid-crystalline SMDs,Z1 and Z2,based on benzodifuran(BDF)units.The amorphous Z2-incorporated ternary devices present an unexpectedly improved power conversion efficiency(PCE)>18%with good stability.By contrast,the highly ordered Z1-based ternary devices possess a significantly depressed efficiency.Multiple characterizations reveal that the Z2-based ternary blend films possess improved miscibility and efficient charge transport.This novel strategy for the selection of the third component is significant for the fabrication of high-efficiency ternary OSCs.展开更多
文摘This study reveals that the interaction between a 2D material and its substrate can significantly modify its electronic and optical properties, and thus can be used as a means to optimize these properties. High-temperature （25-500℃） optical spectroscopy, which combines Raman and photoluminescence spectroscopies, is highly effective for investigating the interaction and material properties that are not accessible at the commonly used cryogenic temperature （e.g., a thermal activation process with an activation of a major fraction of the bandgap）. This study investigates a set of monolayer WS2 films, either directly grown on sapphire and SiO2 substrates by CVD or transferred onto SiO2 substrate. The coupling with the substrate is shown to depend on the substrate type, the material- substrate bonding （even for the same substrate）, and the excitation wavelength. The inherent difference in the states of strain between the as-grown and the transferred films has a significant impact on the material properties.
基金the Ministry of Science and Technology of China(2017YFA0204504)the National Natural Science Foundation of China(51873221,52073292,51673207,21774003,and 51373183)+2 种基金Chinese Academy of Sciences and Dutch Research Project(1A111KYSB20190072)Beijing Municipal Science&Technology Commission(Z181100004418012)Beijing Natural Science Foundation(2212032).
文摘Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve the performance of organic solar cells(OSCs).Contrary to conventional understanding,this research proposes a new strategy for ternary OSCs implicating that"weakly crystalline materials can also optimize the morphology of the active layer and improve the OSCs performance".Herein,we designed and synthesized two liquid-crystalline SMDs,Z1 and Z2,based on benzodifuran(BDF)units.The amorphous Z2-incorporated ternary devices present an unexpectedly improved power conversion efficiency(PCE)>18%with good stability.By contrast,the highly ordered Z1-based ternary devices possess a significantly depressed efficiency.Multiple characterizations reveal that the Z2-based ternary blend films possess improved miscibility and efficient charge transport.This novel strategy for the selection of the third component is significant for the fabrication of high-efficiency ternary OSCs.
