Search

We report here the discovery of a fancy interaction between cesium iodide (CsI) and methylamine (CH3NH2) due to the presence of the hydrogen bond. The formed CsI·xCH3NH2 is a liquid phase, which facilitates the large scale fabrication of highly uniform cesium-containing perovskite films with strong (110) preferred orientation by the CH3NH2 gas healing process. With this method, at most 10% nonpolar Cs cations could fully dope into the crystal lattice and extremely enhance the interaction of the inorganic framework with a more symmetrical PbI6 octahedron, resulting in obvious improvement in moisture stability under continuous illumination. [ABSTRACT FROM AUTHOR]

We report herein the discovery of methylamine (CH3NH2) induced defect-healing (MIDH) of CH3NH3PbI3 perovskite thin films based on their ultrafast (seconds), reversible chemical reaction with CH3NH2 gas at room temperature. The key to this healing behavior is the formation and spreading of an intermediate CH3NH3PbI3⋅ xCH3NH2 liquid phase during this unusual perovskite-gas interaction. We demonstrate the versatility and scalability of the MIDH process, and show dramatic enhancement in the performance of perovskite solar cells (PSCs) with MIDH. This study represents a new direction in the formation of defect-free films of hybrid perovskites. [ABSTRACT FROM AUTHOR]

The incorporation of perfluorooctane iodides into Sn–Pb perovskite solar cells significantly mitigates performance losses caused by ion migration and the internal field shielding effect, while simultaneously enhancing both device efficiency and stability. [ABSTRACT FROM AUTHOR]

Interfacial properties of a hole‐transport material (HTM) and a perovskite layer are of high importance, which can influence the interfacial charge transfer dynamics as well as the growth of perovskite bulk crystals particularly in inverted structure. The halogen bonding (XB) has been recognized as a powerful functional group to be integrated with new small molecule HTMs. Herein, a carbazole‐based halo (iodine)‐functional HTM (O1), is synthesized for the first time, demonstrating a high hole mobility and suitable energy levels that align well with those of perovskites. The strong interaction between O1 and perovskite, i.e., I···I−, induces the formation of an ordered interlayer, which are verified by both theoretical and experimental studies. Compared to the reference HTM (O2) without any halo‐function, the XB‐induced interlayer effectively enhances the interfacial charge extraction efficiency, while significantly hindering the non‐radiative charge recombination by reducing the surface traps upon the strong passivation effect. This is reflected as a big increase in the open‐circuit voltage by up to 114 mV in the fabrication of inverted devices with the highest power conversion efficiency of 22.34%. Moreover, the ordered XB‐driven interlayer at the interface of O1 and perovskite is mainly responsible for the extended lifespan under the operational conditions. [ABSTRACT FROM AUTHOR]

A π-extended tetrathiafulvalene (exTTF) containing a conjugated pentacene moiety showed a large binding affinity toward C60 in solution. The crystal structure analysis of the cocrystal formed by this exTTF and C60 revealed that strong π–π interactions existed between C60 and naphthalene and 1,3-dithiol-2-ylidene units. [ABSTRACT FROM AUTHOR]

The hepatitis B virus (HBV) infects 257 million people worldwide. HBV infection requires establishment and persistence of covalently closed circular (ccc) DNA, a viral episome, in nucleus. Here, we study cccDNA spatial localization in the 3D host genome by using chromosome conformation capture-based sequencing analysis and fluorescence in situ hybridization (FISH). We show that transcriptionally inactive cccDNA is not randomly distributed in host nucleus. Rather, it is preferentially accumulated at specialized areas, including regions close to chromosome 19 (chr.19). Activation of the cccDNA is apparently associated with its re-localization, from a pre-established heterochromatin hub formed by 5 regions of chr.19 to transcriptionally active regions formed by chr.19 and nearby chromosomes including chr.16, 17, 20, and 22. This active versus inactive positioning at discrete regions of the host genome is primarily controlled by the viral HBx protein and by host factors including the structural maintenance of chromosomes protein 5/6 (SMC5/6) complex. [Display omitted] • 4C-seq and FISH analysis locate nuclear positioning of HBV episomal DNA • Transcriptionally inactive cccDNA preferentially co-localizes in Chr.19 • The cccDNA activation associates with localizing to transcriptionally active regions • Positional changes of nuclear HBV are primarily controlled by HBx and SMC5/6 Tang et al. show that the nuclear region around chromosome 19 is a preferred location for transcriptionally inactive HBV cccDNA. Activation of cccDNA associates with re-localization from a heterochromatin hub of chr.19 into its nearby transcriptionally active regions. Positional changes are controlled by HBx and SMC5/6. [ABSTRACT FROM AUTHOR]

Hepatitis B virus (HBV) is a member of the Hepadnaviridae family and infects hepatocytes, leading to liver pathology in acutely and chronically infected individuals. Co-infection with Hepatitis D virus (HDV), which requires the surface proteins of HBV to replicate, can exacerbate this disease progression. Thus, the >250 million people living with chronic HBV infection, including 13 million co-infected with HDV, would significantly benefit from an effective and affordable curative treatment. Animal models are crucial to the development of innovative disease therapies, a paradigm repeated again and again throughout the fields of immunology, neurology, reproduction, and development. Unfortunately, HBV has a highly-restricted species tropism, infecting limited species including humans, chimpanzees, and treeshrews. The first experimentally controlled studies of HBV infection were following inoculation of human volunteers in 1942, which identified the transmissibility of hepatitis through serum transfer and led to the hypothesis that the etiological agent was viral. Subsequent research in chimpanzees (Desmyter et al., 1971; Lichter, 1969) and later in other species, such as the treeshrews (Walter et al., 1996; Yan et al., 1996), further confirmed the viral origin of hepatitis B. Shortly thereafter, HBV-like viral infections were identified in woodchucks (Summers et al., 1978; Werner et al., 1979) and ducks, and much of our understanding of HBV replication can be attributed to these important models. However, with the exodus of chimpanzees from research and the limited reagents and historical data for treeshrews and other understudied species, there remains an urgent need to identify physiologically relevant models of chronic HBV infection. While large strides have been made in generating such models, particularly over the past two decades, there is still no available model that faithfully recapitulates the immunity and pathogenesis of HBV infection. Here, we discuss recent advancements in the generation of murine and non-human primate (NHP) models of HBV/HDV infection. • Chronic HBV infections are a major global health concern. • Multiple mouse models of HBV infection are available. • Macaques are an emerging model of HBV infection. [ABSTRACT FROM AUTHOR]

Quasi−2D perovskite films with multiple quantum well structures can provide a large Stokes shift and efficient photoluminescence (PL), which have great potential in the application of luminescent solar concentrators (LSCs). However, its low photoelectric conversion efficiency and poor stability remain obstacles to commercial application. Here, a multifunctional molecule additive octyltriphenylphosphonium bromide is introduced to prepare high‐quality perovskite LSCs. The multifunctional molecule can simultaneously passivate perovskite cations and anions, reducing the defect sites and improving the photoluminescence quantum yield (PLQY) of the perovskite nanocrystals. Triphenylphosphine groups with high steric hindrance effect can hinder ion migration; the hydrophobic properties of the long alkyl chain prevent water erosion, which together improves the stability of the perovskite films. The multifunctional molecule passivated perovskite film has a high PLQY of 100% and retains 96% of the initial PL intensity after 30 days of indoor storage. The perovskite LSC device achieves a maximum optical efficiency of 6.5% at a geometric factor of 3.1. The findings open a new way to boost the performance of perovskite‐based LSCs. [ABSTRACT FROM AUTHOR]

Reducing non‐radiative recombination caused by defects at buried interfaces is crucial to the development of efficient and stable perovskite solar cells (PSCs). Herein, supramolecular cucurbit[5]uril (CB[5]) is introduced into the SnO2 layer, where it engages in host–guest interactions to suppress oxygen vacancies in SnO2, prevent particle aggregation, and enhance the electron mobility of SnO2. By serving as a bridging agent at the buried interface between SnO2 and the perovskite layer, CB[5] reduces the defect density and improves the carrier extraction efficiency. It also enhanced the surface energy of the SnO2 substrate, facilitates the formation of large grains in the perovskite film, alleviates residual lattice stresses, and enhances the film quality. Consequently, the PSC with CB[5] shows a champion power conversion efficiency of 24.83%. Moreover, an unencapsulated device incorporating CB[5] retains more than 87% of its initial PCE under continuous illumination at the maximum power point tracking for 1000 h. This study pioneers the utilization of cucurbiturils in PSCs and provides insights into how supramolecular compounds can regulate buried interfaces. [ABSTRACT FROM AUTHOR]

Despite numerous studies have reported the inhibition of tin (II) oxidation in mixed tin‐lead halide perovskite, there remains a dearth of mechanistic information regarding how tin (II) undergoes oxidation in the precursor solution, particularly in terms of the involvement of DMSO. We here take advantage of density functional theory (DFT) to uncover that SnI2 can coordinate with DMSO and react with singlet oxygen, resulting in the generation of Sn (IV). Moreover, our DFT simulations reveal that benzaldehyde oxime (BZHO) competes with SnI2 in reacting with oxygen through the Alder‐ene reaction, hence effectively restraining the oxidation of tin (II), which is further verified by several experimental characterizations. Besides, the introduction of BZHO has also regulated the crystallization of the perovskite film and modified the electronic structure of the perovskite surface. As a result, the perovskite solar cells with the addition of BZHO demonstrate superior performance and operational stability, retaining 82 % of the initial PCE under continuous 1‐sun illumination for 800 hours. Furthermore, the efficiency of all‐perovskite tandem solar cells treated with BZHO reached 26.76 %. Therefore, this work presents a promising strategy for designing high‐performance and stable all‐perovskite tandem solar cells. [ABSTRACT FROM AUTHOR]

Introducing fluorine (F) groups into a passivator plays an important role in enhancing the defect passivation effect for the perovskite film, which is usually attributed to the direct interaction of F and defect states. However, the interaction between electronegative F and electron‐rich passivation groups in the same molecule, which may influence the passivation effect, is ignored. We herein report that such interactions can vary the electron cloud distribution around the passivation groups and thus changing their coordination with defect sites. By comparing two fluorinated molecules, heptafluorobutylamine (HFBM) and heptafluorobutyric acid (HFBA), we find that the F/−NH2 interaction in HFBM is stronger than the F/−COOH one in HFBA, inducing weaker passivation ability of HFBM than HFBA. Accordingly, HFBA‐based perovskite solar cells (PSCs) provide an efficiency of 24.70 % with excellent long‐term stability. Moreover, the efficiency of a large‐area perovskite module (14.0 cm2) based on HFBA reaches 21.13 %. Our work offers an insight into understanding an unaware role of the F group in impacting the passivation effect for the perovskite film. [ABSTRACT FROM AUTHOR]

High‐performance perovskite solar cells have demonstrated commercial viability, but still face the risk of contamination from lead leakage and long‐term stability problems caused by defects. Here, an organic small molecule (octafluoro‐1,6‐hexanediol diacrylate) is introduced into the perovskite film to form a polymer through in situ thermal crosslinking, of which the carbonyl group anchors the uncoordinated Pb2+ of perovskite and reduces the leakage of lead, along with the −CF2− hydrophobic group protecting the Pb2+ from water invasion. Additionally, the polymer passivates varieties of Pb‐related and I‐related defects through coordination and hydrogen bonding interactions, regulating the crystallization of perovskite film with reduced trap density, releasing lattice strain, and promoting carrier transport and extraction. The optimal efficiencies of polymer‐incorporated devices are 24.76 % (0.09 cm2) and 20.66 % (14 cm2). More importantly, the storage stability, thermal stability, and operational stability have been significantly improved. [ABSTRACT FROM AUTHOR]