Isomerization of Benzothiadiazole Yields a Promising Polymer Donor and Organic Solar Cells with Efficiency of 19.0.

The exploration of high-performance and low-cost wide-bandgap polymer donors remains critical to achieve high-efficiency nonfullerene organic solar cells (OSCs) beyond current thresholds. Herein, the 1,2,3-benzothiadiazole (iBT), which is an isomer of 2,1,3-benzothiadiazole (BT), is used to design wide-bandgap polymer donor PiBT. The PiBT-based solar cells reach efficiency of 19.0%, which is one of the highest efficiencies in binary OSCs. Systemic studies show that isomerization of BT to iBT can finely regulate the polymers' photoelectric properties including i) increasing the extinction coefficient and photon harvest, ii) downshifting the highest occupied molecular orbital energy levels, iii) improving the coplanarity of polymer backbones, iv) offering good thermodynamic miscibility with acceptors. Consequently, the PiBT:Y6 bulk heterojunction (BHJ) device simultaneously reaches advantageous nanoscale morphology, efficient exciton generation and dissociation, fast charge transportation, and suppressed charge recombination, leading to larger VOC of 0.87 V, higher JSC of 28.2 mA cm-2, greater fill factor of 77.3%, and thus higher efficiency of 19.0%, while the analog-PBT-based OSCs reach efficiency of only 12.9%. Moreover, the key intermediate iBT can be easily afforded from industry chemicals via two-step procedure. Overall, this contribution highlights that iBT is a promising motif for designing high-performance polymer donors.

Step-by-Step Modulation of Crystalline Features and Exciton Kinetics for 19.2% Efficiency Ortho-Xylene Processed Organic Solar Cells.

With plenty of popular and effective ternary organic solar cells (OSCs) construction strategies proposed and applied, its power conversion efficiencies (PCEs) have come to a new level of over 19% in single-junction devices. However, previous studies are heavily based in chloroform (CF) leaving behind substantial knowledge deficiencies in understanding the influence of solvent choice when introducing a third component. Herein, we present a case where a newly designed asymmetric small molecular acceptor using fluoro-methoxylated end-group modification strategy, named BTP-BO-3FO with enlarged bandgap, brings different morphological evolution and performance improvement effect on host system PM6:BTP-eC9, processed by CF and ortho-xylene (o-XY). With detailed analyses supported by a series of experiments, the best PCE of 19.24% for green solvent-processed OSCs is found to be a fruit of finely tuned crystalline ordering and general aggregation motif, which furthermore nourishes a favorable charge generation and recombination behavior. Likewise, over 19% PCE can be achieved by replacing spin-coating with blade coating for active layer deposition. This work focuses on understanding the commonly met yet frequently ignored issues when building ternary blends to demonstrate cutting-edge device performance, hence, will be instructive to other ternary OSC works in the future.

[Chemical constituents from whole plants of Aconitum tanguticum].

Nineteen compounds were isolated from the whole plants of Aconitum tanguticum by means of various of chromatographic techniques such as silica gel, ODS, sephadex LH-20 and preparative HPLC, and their structures were elucidated as syringin (1), vanillic acid-4-O-beta-D-allopyranoside (2), (E) -ferulic acid 4-O-beta-D-allopyranoside (3), (E) -ferulic acid-4-O-beta-glucopysoside (4), (E) -sinapic acid-4-O-beta-glucopyranoside (5), (E) 4-hydroxycinnamyl alcohol 4-O-beta-D-glucopyranoside (6), quercetin 3-O-alpha-L-rhamnopyranosyl-(1 --> 2) -[alpha-L-rhamnopyranosyl-(1 --> 6)] -beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (7), kaempferol 3-O-alpha-L-rhamnopyranosyl-(1 --> 2) - [alpha-L-rhamnopyranosyl-(1 --> 6)] -beta-D-galactopyranside-7-O-alpha-L-rhamnopyranoside (8), quercetin 3-O-alpha-L-rhamnopyranosyl-(1 --> 6) -beta-D-glucopyranoside-7-O-alpha-L-rhamnopyranoside (9), kaempferol 3-O-[beta-D-glucopyranosyl-(1 --> 3)-(4-O-trans-p-coumaroyl) ] -alpha-L-rhamnopyranosyl-(1 --> 6) -beta-D-galactopyranside-7-O-alpha-L-rhamnopyranoside (10), quercetin 3-O- [beta-D-glucopyranosyl-(1 --> 3 ) -(4-O-trans-p-coumaroyl)] -alpha-L-rhamnopyranosyl-(1--> 6) -beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (11), salidroside (12), 2-(3,4-dihydroxyphenyl) ethanol 1-O-beta-D-glucopyranoside (13), (7S, 8R) -dehydrodiconiferyl alcohol-9'-O-beta-D-glucopyranoside (14), citrusin B (15), heteratisine (16), tanaconitine (17), shanzhiside methyl ester (18) and icariside B1 (19). Except compounds 4, 13, 16 and 17, the other compounds were separated from the species for the first time.