Search

In recent years, perovskite has been widely adopted in series-connected monolithic tandem solar cells (TSCs) to overcome the Shockley–Queisser limit of single-junction solar cells. Perovskite–organic TSCs, comprising a wide-bandgap (WBG) perovskite solar cell (pero-SC) as the front cell and a narrow-bandgap organic solar cell (OSC) as the rear cell, have recently drawn attention owing to the good stability and potential high power conversion efficiency (PCE)1–4. However, WBG pero-SCs usually exhibit higher voltage losses than regular pero-SCs, which limits the performance of TSCs5,6. One of the main obstacles comes from interfacial recombination at the perovskite–C60interface, and it is important to develop effective surface passivation strategies to pursue higher PCE of perovskite–organic TSCs7. Here we exploit a new surface passivator cyclohexane 1,4-diammonium diiodide (CyDAI2), which naturally contains two isomeric structures with ammonium groups on the same or opposite sides of the hexane ring (denoted as cis-CyDAI2and trans-CyDAI2, respectively), and the two isomers demonstrate completely different surface interaction behaviours. The cis-CyDAI2passivation treatment reduces the quasi-Fermi-level splitting–open circuit voltage (Voc) mismatch of the WBG pero-SCs with a bandgap of 1.88 eV and enhanced its Vocto 1.36 V. Combining the cis-CyDAI2-treated perovskite and the organic active layer with a narrow bandgap of 1.27 eV, the constructed monolithic perovskite–organic TSC demonstrates a PCE of 26.4% (certified as 25.7%).

Organic photovoltaic (OPV) is one of the most promising technologies for powering indoor electronic devices. The high-performance indoor organic photovoltaics (IOPV) require medium bandgap materials to absorb visible light efficiently and reduce energy loss. However, state-of-the-art A-DA’D-A type small molecule acceptors (SMAs) have absorptions in the near-infrared region which mismatches with the room light. In this work, two medium bandgap A-DA’D-A type SMAs BTOL-Br and DFOL-Br were synthesized by a molecular synergetic modification strategy for the applications in IOPV. Our results show that DFOL-Br with replacing the A’ unit of benzothiadiazole in BTOL-Br by difluorine substituted benzene ring, exhibits blue-shifted absorption spectra and an up-shifted lowest unoccupied molecular orbital (LUMO) energy level than those of BTOL-Br. When blending the SMAs with a polymer donor PBQx-TCl, the DFOL-Br-based film shows more ordered molecular packing and suitable phase separation. As a result, the DFOL-Br-based device achieves a higher indoor efficiency of 26.8% under a 2600 K light-emitting diode lamp at 2000 lux than that of the BTOL-Br-based one (23.2%). This work indicates that the synergetic modification is an effective strategy for preparing medium bandgap A-DA’D-A type SMAs, which may become a useful SMA design guideline for developing high-performance IOPVs.

The medium-bandgap polymerized small molecule acceptors (PSMAs) have broad application scenarios. However, the effort in the molecular design of the high-performance medium-bandgap PSMAs is limited. In this article, we introduce alkoxy groups as outer side chains and as substituents of the thiophene π-bridges of the high-performance PSMA PY-IT to synthesize a medium-bandgap PSMA PO-TO. Due to that the non-covalent interaction between the alkoxy groups and the terminal groups of the small molecule acceptor (SMA) unit can weaken the intramolecular charge transfer (ICT) effect, the bandgap of PO-TO is enlarged and its absorption is blue-shifted compared with PY-IT, while the absorbance of PO-TO solution and film is enhanced significantly compare with that of PY-IT. When blended PO-TO with the polymer donor PBQx-TF, the corresponding all-polymer solar cells (all-PSCs) exhibit an open-circuit voltage (Voc) exceeding 1.04 V with a power conversion efficiency (PCE) of 13.75%. Furthermore, PO-TO was used as the third component to fabricate ternary all-PSCs with PBQx-TF as the polymer donor and PY-IT as the main polymer acceptor, and the ternary all-PSCs based on PBQx-TF:PY-IT:PO-TO (1:1:0.2, w/w/w) demonstrated a high PCE of 17.71% with simultaneously improved Vocof 0.940 V, short-circuit current density (Jsc) of 24.60 mA cm−2and fill factor (FF) of 76.81%. In comparison, the binary all-PSCs based on PBQx-TF:PY-IT showed a PCE of 16.77%. This result indicates that introducing alkoxy groups is a promising strategy for synthesizing high-performance medium-bandgap PSMAs.

Employing self-solvent vapor annealing, we have meticulously optimized the donor layer morphology. The π-π stacking and crystal coherence length of PM6 molecules are enhanced to achieve efficient charge transport, improving power conversion efficiency from 17.7% to 18.2%.

The evaluation of toxicity and environmental behavior of bioactive lead molecules is helpful in providing theoretical support for the development of agrochemicals, in line with the sustainable development of the ecological environment. In previous work, some acethydrazide structures have been demonstrated to exhibit excellent and broad-spectrum fungicidal activity; however, its environmental compatibility needs to be further elucidated if it is to be identified as a potential fungicide. In this project, the toxicity of fungicidal acethydrazide lead compounds F51, F58, F72, and F75 to zebrafish was determined at 10 μg mL–1and 1 μg mL–1. Subsequently, the toxic mechanism of compound F58 was preliminarily explored by histologic section and TEM observations, which revealed that the gallbladder volume of common carp treated with compound F58 increased, accompanied by a deepened bile color, damaged plasma membrane, and atrophied mitochondria in gallbladder cells. Approximately, F58-treated hepatocytes exhibited cytoplasmic heterogeneity, with partial cellular vacuolation and mitochondrial membrane rupture. Metabolomics analysis further indicated that differential metabolites were enriched in the bile formation-associated steroid biosynthesis, primary bile acid biosynthesis, and taurine and hypotaurine metabolism pathways, as well as in the membrane function-related glycerophospholipid metabolism, linolenic acid metabolism, α-linolenic acid metabolism, and arachidonic acid metabolism pathways, suggesting that the acethydrazide F58 may have acute liver toxicity to common carp. Finally, the hydrolysis dynamics of F58 was investigated, with the obtained half-life of 5.82 days. The above results provide important guiding significance for the development of new green fungicides.