RESUMO
Multicomponent organic solar cells (OSCs), such as the ternary and quaternary OSCs, not only inherit the simplicity of binary OSCs but further promote light harvesting and power conversion efficiency (PCE). Here, we propose a new type of multicomponent solar cells with non-fullerene acceptor isomers. Specifically, we fabricate OSCs with the polymer donor J71 and a mixture of isomers, ITCF, as the acceptors. In comparison, the ternary OSC devices with J71 and two structurally similar (not isomeric) NFAs (IT-DM and IT-4F) are made as control. The morphology experiments reveal that the isomers-containing blend film demonstrates increased crystallinity, more ideal domain size, and a more favorable packing orientation compared with the IT-DM/IT-4F ternary blend. The favorable orientation is correlated with the balanced charge transport, increased exciton dissociation and decreased bimolecular recombination in the ITCF-isomer-based blend film, which contributes to the high fill factor (FF), and thus the high PCE. Additionally, to evaluate the generality of this method, we examine other acceptor isomers including IT-M, IXIC-2Cl and SY1, which show same trend as the ITCF isomers. These results demonstrate that using isomeric blends as the acceptor can be a promising approach to promote the performance of multicomponent non-fullerene OSCs.
RESUMO
Radix Astragali (RA) is one of the most frequently used traditional Chinese medicine (TCM) in China, and honey-processed RA (HRA) is its common processing product. Thus far, their comprehensive chemical differences are not well understood. In this work, an integrated approach using Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) combined with diagnostic ions, molecular network (MN) and chemometrics was established to profile their chemical characterizations and illustrate the chemical mechanism of RA processed with honey. A total of 226 compounds were tentatively identified including 50 flavonoid glycosides, 26 flavonoid aglycone, 56 saponins, 30 organic acids, 18 amino acids, 3 coumarins and 43 other compounds, of which 33 compounds were characterized according to MN. Their chemical differences were further investigated by integrating of multivariate statistical analysis, student's t-test analysis, linear regression analysis and MN. Consequently, multivariate statistical analysis showed that the raw and processed RA were different form each other. Besides, 33 different compounds were found to be significantly altered by student's t-test analysis. Apart from this, linear regression analysis indicated 42 and 120 compounds underwent the significant varieties. The potential chemical reactions induced by honey-processing, such as possible hydrolysis reactions and isomerization reactions, were speculated based on these variations coupled the areas changes of the nodes in MN. This study provided an efficient strategy to illustrate the chemical mechanism of TCM processing.
RESUMO
PEDOT: PSS is the most popular hole-transporting material (HTM) for conventional structural organic solar cell (OSC) devices, whose performance is of great importance for realizing high power conversion efficiency (PCE). However, its performance in OSC devices has been continuously challenged by various replacing materials and different doping strategies, for better conductivity, work function, and surface property. Here, we report a simple dopant-free method to tune the phase separation of the PEDOT:PSS layer, which results in better charge transport and extraction in devices. Specifically, high PCEs for binary polymer-small-molecule (>18%) and polymer-polymer (>17%) systems are simultaneously achieved. This work engineeringly provides encouraging improvement for OSC device performance with easy modification and scientifically offers insights into tuning the property of the PEDOT:PSS layer.