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A double-fibril network of the photoactive layer morphology is recognized as an ideal structure facilitating exciton diffusion and charge carrier transport for high-performance organic solar cells (OSCs). However, in the layer-by-layer processed OSCs (LbL-OSCs), polymer donors and small molecule acceptors (SMAs) are separately deposited, and it is challenging to realize a fibril network of pure SMAs with the absence of tight interchain entanglement as polymers. In this work, crystalline small molecule donors (SMDs), named TDZ-3TR and SeDZ-3TR, were designed and introduced into the L8-BO acceptor solution, forcing the phase separation and molecular fibrilization. SeDZ-3TR showed higher crystallinity and lower miscibility with L8-BO acceptor than TDZ-3TR, enabling more driving force to favor the phase separation and better molecular fibrilization of L8-BO. On the other hand, two donor polymers of PM6 and D18 with different fibril widths and lengths were put together to optimize the fibril network of the donor layer. The simultaneously optimization of the acceptor and donor layers resulted in a more ideal double-fibril network of the photoactive layer and an impressive power conversion efficiency (PCE) of 19.38 % in LbL-OSCs., (© 2024 Wiley-VCH GmbH.)

The success of Y6-type nonfullerene small molecule acceptors (NF-SMAs) in polymer solar cells (PSCs) can be attributed to their unique honeycomb stacking style, which leads to favorable thin-film morphologies. The intermolecular interactions related to the crystallization tendency of these NF-SMAs is closely governed by their electron accepting end groups. For example, the high performance Y6 derivative L8-BO (BTP-4F) presents three types of stacking modes in contrast to two stacking modes of Y6. Hence, it is ultimately interesting to obtain more insight on the packing properties and the preferences influenced by chemical modifications such as end group engineering. This work designs and synthesizes asymmetric and symmetric L8-BO derivatives with brominated end groups and explores the stacking preferences in various modes. The asymmetric BTP-3FBr displays an optimized crystallization tendency and thin film morphology, leading to a decent power conversion efficiency (PCE) of 18.34% in binary devices and a top PCE of 19.32% in ternary devices containing 15 wt% IDIC as the second acceptor., (© 2023 Wiley-VCH GmbH.)

Lasso peptides are ribosomally synthesized peptides that undergo post-translational modifications including leader peptide removal by B (or the segregated B1 and B2) proteins and core peptide macrolactamization by C proteins to form a unique lariat topology. A conserved threonine residue at the penultimate position of leader peptide is hitherto found in lasso peptide precursors and shown to be a critical recognition element for effective enzymatic processing. We identified a lasso peptide biosynthetic gene cluster ( bsf ) from Bradymonas sediminis FA350, a Gram-negative and facultatively prey-dependent bacterium that belongs to a novel bacterial order Bradymonadales in the class Deltaproteobacteria . The kinase BsfK specifically catalyzes the phosphorylation of the precursor peptide BsfA on the Ser3 residue. BsfB1 performs dual functions to accelerate the post-translational phosphorylation and assist BsfB2 in leader peptide removal. Most importantly, the penultimate residue of leader peptide is an isoleucine rather than the conserved threonine and this isoleucine has a marked impact on the phosphorylation of Ser3 as well as leader peptide removal, implying that BsfB1 and BsfB2 exhibit a new substrate selectivity for leader peptide binding and excision. This is the first experimentally validated penultimate isoleucine residue in a lasso peptide precursor to our knowledge. In silico analysis reveals that the leader peptide Ile/Val(-2) residue is rare but not uncommon in phosphorylated lasso peptides, as this residue is also discovered in Acidobacteriaceae and Sphingomonadales in addition to Bradymonadales ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Duan, Niu, Pang, Mu, Du, Zhang, Bian and Zhong.)

Cesium lead triiodide (CsPbI 3 ) is a promising light-absorbing material for constructing perovskite solar cells (PSCs) owing to its favorable bandgap and thermal tolerance. However, the high density of defects in the CsPbI 3 film not only act as recombination centers, but also facilitate ion migration, leading to lower PCE and inferior stability compared with the state-of-the-art organic-inorganic hybrid PSC counterpart. Theoretical analyses suggest that the effective suppression of defects in CsPbI 3 film is helpful for improving the device performance. Herein, the stable and efficient γ -CsPbI 3 PSCs are demonstrated by developing an acyloin ligand (1,2-di(thiophen-2-yl)ethane-1,2-dione (DED)) as a phase stabilizer and defect passivator. The experiment and calculation results confirm that carbonyl and thienyl in DED can synergistically interact with CsPbI 3 by forming a chelate to effectively passivate Pb-related defects and further suppress ion migration. Consequently, DED-treated CsPbI 3 PSCs yield a champion PCE of 21.15%, which is one of the highest PCE among all the reported CsPbI 3 PSCs to date. In addition, the unencapsulated DED-CsPbI 3 PSC can retain 94.9% of itsinitial PCE when stored under ambient conditions for 1000 h and 92.8% of its initial PCE under constant illumination for 250 h., (© 2023 Wiley-VCH GmbH.)

All-inorganic CsPbI 3 perovskite solar cells (PSCs) have been extensively studied due to their high thermal stability and unprecedented rise in power conversion efficiency (PCE). Recently, the champion PCE of CsPbI 3 PSCs has reached up to 21%; however, it is still much lower than that of organic-inorganic hybrid PSCs. Interface modification to passivate surface defects and minimize charge recombination and trapping is important to further improve the efficiency of CsPbI 3 PSCs. Herein, a new zwitterion ion is deposited at the interface between electron transporting layer (ETL) and perovskite layer to passivate the defects therein. The zwitterion ions can not only passivate oxygen vacancy (V O ) and iodine vacancy (V I ) defects, but also improve the band alignment at the ETL-perovskite interface. After the interface treatment, the PCE of CsPbI 3 device reaches up to 20.67%, which is among the highest values of CsPbI 3 PSCs so far. Due to the defect passivation and hydrophobicity improvement, the PCE of optimized device remains 94% of its original value after 800 h storing under ambient condition. These results provide an efficient way to improve the quality of ETL-perovskite interface by zwitterion ions for achieving high performance inorganic CsPbI 3 PSCs., (© 2022 Wiley-VCH GmbH.)

Side-chain engineering with heteroatoms is not only effective in tuning frontier molecular orbitals, but also possible for forming secondary bonds which can be utilized to planarize the molecular backbone, hence, improving the photon absorption as well as charge-transport abilities of polymer solar-cell (PSC) materials. Herein, two types of unconventional side chains, namely carboxylate and carbamate, containing various heteroatoms are introduced to the thiophene bridges in high performance benzodithiophene (BDT) based donor polymers to from the novel polymers PTzTz-C and PTzTz-N, respectively. In these polymers, non-covalent O⋅⋅⋅S and N⋅⋅⋅H interactions induce a high tendency to aggregation. In a ternary-blend PSC with PTzTz-N added to the high-performance D18 : BTP-eC9 blend, complimentary absorption and improved thin-film morphology were observed with a top power conversion efficiency of 18.76 %, which is an improvement of almost 5 % over the D18 : BTP-eC9 binary blends., (© 2022 Wiley-VCH GmbH.)