Organic Passivation-Enhanced Ferroelectricity in Perovskite Oxide Films.

Perovskite oxides and organic-inorganic halide perovskite materials, with numerous fascinating features, have been subjected to extensive studies. Most of the properties of perovskite materials are dependence on their ferroelectricity that denoted by remanent polarization (Pr). Thus, the increase of Pr in perovskite films is mainly an effort in material physics. At present, commonplace improvement schemes, i.e., controlling material crystallinity, and post-annealing by using a high-temperature process, are normally used. However, a simpler and temporal strategy for Pr improvement is always unavailable to perovskite material researchers. In this study, an organic coating layer, low-temperature, and vacuum-free strategy is proposed to improve the Pr, directly increasing the Pr from 36 to 56 µC cm-2. Further study finds that the increased Pr originates from the suppression of the oxygen defects and Ti defects. This organic coating layer strategy for passivating the defects may open a new way for the preparation of higher-performance and cost-effective perovskite products, further improving its prospective for application in the electron devices field.

An emerging terpolymeric nanoparticle pore former as an internal recrystallization inhibitor of celecoxib in controlled release amorphous solid dispersion beads: Experimental studies and molecular dynamics analysis.

Solid oral controlled release formulations feature numerous clinical advantages for drug candidates with adequate solubility and dissolution rate. However, most new chemical entities exhibit poor water solubility, and hence are exempt from such benefits. Although combining drug amorphization with controlled release formulation is promising to elevate drug solubility, like other supersaturating systems, the problem of drug recrystallization has yet to be resolved, particularly within the dosage form. Here, we explored the potential of an emerging, non-leachable terpolymer nanoparticle (TPN) pore former as an internal recrystallization inhibitor within controlled release amorphous solid dispersion (CRASD) beads comprising a poorly soluble drug (celecoxib) reservoir and insoluble polymer (ethylcellulose) membrane. Compared to conventional pore former, polyvinylpyrrolidone (PVP), TPN-containing membranes exhibited superior structural integrity, less crystal formation at the CRASD bead surface, and greater extent of celecoxib release. All-atom molecular dynamics analyses revealed that in the presence of TPN, intra-molecular bonding, crystal formation tendency, diffusion coefficient, and molecular flexibility of celecoxib were reduced, while intermolecular H-bonding was increased as compared to PVP. This work suggests that selection of a pore former that promotes prolonged molecular separation within a nanoporous controlled release membrane structure may serve as an effective strategy to enhance amorphicity preservation inside CRASD.

The Development of Carbon/Silicon Heterojunction Solar Cells through Interface Passivation.

Passivating contactsin heterojunction (HJ) solar cells have shown great potential in reducing recombination losses, and thereby achieving high power conversion efficiencies in photovoltaic devices. In this direction, carbon nanomaterials have emerged as a promising option for carbon/silicon (C/Si) HJsolar cells due to their tunable band structure, wide spectral absorption, high carrier mobility, and properties such as multiple exciton generation. However, the current limitations in efficiency and active area have hindered the industrialization of these devices. In this review, they examine the progress made in overcoming these constraints and discuss the prospect of achieving high power conversion efficiency (PCE) C/Si HJ devices. A C/Si HJ solar cell is also designed by introducing an innovative interface passivation strategy to further boost the PCE and accelerate the large area preparationof C/Si devices. The physical principle, device design scheme, and performanceoptimization approaches of this passivated C/Si HJ cells are discussed. Additionally, they outline potential future pathways and directions for C/Si HJ devices, including a reduction in their cost to manufacture and their incorporation intotandem solar cells. As such, this review aims to facilitate a deeperunderstanding of C/Si HJ solar cells and provide guidance for their further development.

Membrane Protein Structures in Native Cellular Membranes Revealed by Solid-State NMR Spectroscopy.

The structural characterization of membrane proteins within the cellular membrane environment is critical for understanding the molecular mechanism in their native functional context. However, conducting residue site-specific structural analysis of membrane proteins in native membranes by solid-state NMR faces challenges due to poor spectral sensitivity and serious interference from background protein signals. In this study, we present a new protocol that combines various strategies for cellular membrane sample preparations, enabling us to reveal the secondary structure of the mechanosensitive channel of large conductance from Methanosarcina acetivorans (MaMscL) in Escherichia coli inner membranes. Our findings demonstrate the feasibility of achieving complete resonance assignments and the potential for determining the 3D structures of membrane proteins within cellular membranes. We find that the use of the BL21(DE3) strain in this protocol is crucial for effectively suppressing background protein labeling without compromising the sensitivity of the target protein. Furthermore, our data reveal that the structures of different proteins exhibit varying degrees of sensitivity to the membrane environment. These results underscore the significance of studying membrane proteins within their native cellular membranes when performing structural characterizations. Overall, this study opens up a new avenue for achieving the atomic-resolution structural characterization of membrane proteins within their native cellular membranes, providing valuable insights into the nativeness of membrane proteins.

Polarization-Sensitive, Self-Powered, and Broadband Semimetal MoTe2/MoS2 van der Waals Heterojunction for Photodetection and Imaging.

The emerging type II Weyl semimetal 1T' MoTe2 as a promising material in polarization-sensitive photodetectors has aroused much attention due to its narrow bandgap and intrinsic in-plane anisotropic crystal structure. However, the semimetal properties lead to a large dark current and a low response. Herein, we demonstrate for the first time an all-2D semimetal MoTe2/MoS2 van der Waals (vdWs) heterojunction to improve the performance of the photodetectors and realize polarization-sensitive, self-powered, and broadband photodetection and imaging. Owing to the built-in electric field of the heterojunction, the device achieves a self-powered photoresponse ranging from 520 to 1550 nm. Under 915 nm light illumination, the device demonstrates outstanding performance, including a high responsivity of 79 mA/W, a specific detectivity of 1.2 × 1010 Jones, a fast rise/decay time of 180/202 µs, and a high on/off ratio of 1.3 × 10.3 Wavelength-dependent photocurrent anisotropic ratio is revealed to vary from 1.10 at 638 nm to 2.24 at 1550 nm. Furthermore, we demonstrate the polarization imaging capabilities of the device in scattering surroundings, and the DoLP and AoLP images achieve 78% and 112% contrast enhancement, respectively, compared to the S0. This work opens up new avenues to develop anisotropic semimetals heterojunction photodetectors for high-performance polarization-sensitive photodetection and next-generation polarized imaging.

Improvement of duplex-specific nuclease salt tolerance by fusing DNA-binding domain of DNase from an extremely halotolerant bacterium Thioalkalivibrio sp. K90mix.

Salt tolerance is an important property of duplex-specific nuclease (DSN). DSN with high salt tolerance can be more widely used in genetic engineering, especially in the production of nucleic acid drugs. To improve the salt tolerance of DSN, we selected five DNA-binding domains from extremophilic organisms, which have been shown the ability to improve salt tolerance of DNA polymerases and nucleases. The experimental results demonstrated that the fusion protein TK-DSN produced by fusing a N-terminal DNA-binding domain, which comprised two HhH (helix-hairpin-helix) motifs domain from an extremely halotolerant bacterium Thioalkalivibrio sp. K90mix, has a significantly improved salt tolerance. TK-DSN can tolerate the concentration of NaCl up to 800 mM; in addition, the ability of digesting DNA was also enhanced during in vitro transcription and RNA purification. This strategy provides the method for the personalized customization of biological tool enzymes for different applications.

Organic Passivation of Deep Defects in Cu(In,Ga)Se2 Film for Geometry-Simplified Compound Solar Cells.

Diverse defects in copper indium gallium diselenide solar cells cause nonradiative recombination losses and impair device performance. Here, an organic passivation scheme for surface and grain boundary defects is reported, which employs an organic passivation agent to infiltrate the copper indium gallium diselenide thin films. A transparent conductive passivating (TCP) film is then developed by incorporating metal nanowires into the organic polymer and used in solar cells. The TCP films have a transmittance of more than 90% in the visible and nearinfrared spectra and a sheet resistance of ~10.5 Ω/sq. This leads to improvements in the open-circuit voltage and the efficiency of the organic passivated solar cells compared with control cells and paves the way for novel approaches to copper indium gallium diselenide defect passivation and possibly other compound solar cells.

Lifetime over 10000 hours for organic solar cells with Ir/IrOx electron-transporting layer.

The stability of organic solar cells is a key issue to promote practical applications. Herein, we demonstrate that the device performance of organic solar cells is enhanced by an Ir/IrOx electron-transporting layer, benefiting from its suitable work function and heterogeneous distribution of surface energy in nanoscale. Notably, the champion Ir/IrOx-based devices exhibit superior stabilities under shelf storing (T80 = 56696 h), thermal aging (T70 = 13920 h), and maximum power point tracking (T80 = 1058 h), compared to the ZnO-based devices. It can be attributed to the stable morphology of photoactive layer resulting from the optimized molecular distribution of the donor and acceptor and the absence of photocatalysis in the Ir/IrOx-based devices, which helps to maintain the improved charge extraction and inhibited charge recombination in the aged devices. This work provides a reliable and efficient electron-transporting material toward stable organic solar cells.

Achieving High Responsivity and Detectivity in a Quantum-Dot-in-Perovskite Photodetector.

This work reports on quantum dots (QDs) in perovskite photodetectors showing high optoelectronic performance via quantum-dot-assisted charge transmission. The self-powered broad-band photodetector constructed with SnS QDs in FAPb0.5Sn0.5I3 perovskite can capture incoming optical signals directly at zero bias. The QDs-in-perovskite photodetector exhibits a high sensitivity in the wavelength range from 300 to 1000 nm. Its responsivity at 850 nm reaches 521.7 mA W-1, and a high specific detectivity of 2.57 × 1012 jones can be achieved, which is well beyond the level of previous self-powered broad-band photodetectors. The capability of quantum-dot-in-perovskite photodetectors as data receivers has been further demonstrated in a visible-light communication application.

Design and Optimization of a Nanoparticulate Pore Former as a Multifunctional Coating Excipient for pH Transition-Independent Controlled Release of Weakly Basic Drugs for Oral Drug Delivery.

Bioavailability of weakly basic drugs may be disrupted by dramatic pH changes or unexpected pH alterations in the gastrointestinal tract. Conventional organic acids or enteric coating polymers cannot address this problem adequately because they leach out or dissolve prematurely, especially during controlled release applications. Thus, a non-leachable, multifunctional terpolymer nanoparticle (TPN) made of cross-linked poly(methacrylic acid) (PMAA)-polysorbate 80-grafted-starch (PMAA-PS 80-g-St) was proposed to provide pH transition-independent release of a weakly basic drug, verapamil HCl (VER), by a rationally designed bilayer-coated controlled release bead formulation. The pH-responsive PMAA and cross-linker content in the TPN was first optimized to achieve the largest possible increase in medium uptake alongside the smallest decrease in drug release rate at pH 6.8, relative to pH 1.2. Such TPNs maintained an acidic microenvironmental pH (pHm) when loaded in ethylcellulose (EC) films, as measured using pH-indicating dyes. Further studies of formulations revealed that with the 1:2 VER:TPN ratio and 19% coating weight gain, bilayer-coated beads maintained a constant release rate over the pH transition and exhibited extended release up to 18 h. These results demonstrated that the multifunctional TPN as a pHm modifier and pH-dependent pore former could overcome the severe pH-dependent solubility of weakly basic drugs.

Dynamic Interactions Between Brilliant Green and MscL Investigated by Solid-State NMR Spectroscopy and Molecular Dynamics Simulations.

The mechanosensitive ion channel of large conductance (MscL) is a promising template for the development of new antibiotics due to its high conservation and uniqueness to microbes. Brilliant green (BG), a triarylmethane dye, has been identified as a new antibiotic targeted MscL. However, the detailed binding sites to MscL and the dynamic pathway of BG through the MscL channel remain unknown. Here, the dynamic interactions between BG and MscL were investigated using solid-state NMR spectroscopy and molecule dynamics (MD) simulations. Residue site-specific binding sites of BG to the MscL channel were identified by solid-state NMR. In addition, MD simulations revealed that BG conducts through the MscL channel via residues along the inner surface of the pore sequentially, in which the strong hydrophobic interactions between BG and hydrophobic residues F23 and I27 in the hydrophobic gate region of the MscL channel are major restrictions. Particularly, it was demonstrated that BG activates the MscL channel by reducing the hydrophobicity of the F23 in the gate region by water molecules that are bound to BG. Taken together, these simulations and experimental data provide novel insights into the dynamic interactions between BG and MscL, based on which new hydrophobic antibiotics and adjuvants targeting MscL can be developed.

Multi-Carrier Generation in Organic-Passivated Black Silicon Solar Cells with Industrially Feasible Processes.

The innate inverse Auger effect within bulk silicon can result in multiple carrier generation. Observation of this effect is reliant upon low high-energy photon reflectance and high-quality surface passivation. In the photovoltaics industry, metal-assisted chemical etching (MACE) to afford black silicon (b-Si) can provide a low high-energy photon reflectance. However, an industrially feasible and cheaper technology to conformally passivate the outer-shell defects of these nanowires is currently lacking. Here, a technology is introduced to infiltrate black silicon nanopores with a simple and vacuum-free organic passivation layer that affords millisecond-level minority carrier lifetimes and matches perfectly with existing solution-based processing of the MACE black silicon. Advancements such as the demonstration of an excellent passivation effect whilst also being low reflectance provide a new technological route for inverse Auger multiple carrier generation and an industrially feasible technical scheme for the development of the MACE b-Si solar cells.

Disinfection effect of hexadecyl pyridinium chloride on SARS-CoV-2 in vitro.

The novel coronavirus (COVID-19 or 2019-nCoV) is a respiratory virus that can exist in the mouth and saliva of patients and spreads through aerosol dispersion. Therefore, stomatological hospitals and departments have become high-infection-risk environments. Accordingly, oral disinfectants that can effectively inactivate the virus have become a highly active area of research. Hexadecyl pyridinium chloride, povidone-iodine, and other common oral disinfectants are the natural primary choices for stomatological hospitals. Therefore, this study investigated the inhibitory effect of hexadecyl pyridinium chloride on SARS-CoV-2 in vitro. Vero cells infected with SARS-CoV-2 were used to determine the disinfection effect; the CCK-8 method was used to determine cytotoxicity, and viral load was determined by real-time PCR. The results showed that hexadecyl pyridinium chloride has no obvious cytotoxic effect on Vero cells in the concentration range 0.0125-0.05 mg/mL. The in vitro experiments showed that hexadecyl pyridinium chloride significantly inhibits the virus at concentrations of 0.1 mg/mL or above at 2 min of action. Thus, the results provide experimental support for the use of hexadecyl pyridinium chloride in stomatological hospitals.

Solid-state NMR 13C and 15 N resonance assignments of Vibrio sp. SemiSWEET transporter in lipid bilayers.

The Sugar Will Eventually be Exported Transporter (SWEET) family is a new class of transporters that plays crucial roles in the cellular sugar transport process. Their bacterial homologs, known as SemiSWEETs, are among the smallest transporters and can be used as a prototype for studying the biological properties of sugar transporters. Here, a set of dipolar-based multidimensional solid-state NMR spectra were employed to investigate the structure of Vibrio sp. SemiSWEET (Vs-SemiSWEET) reconstituted in the native-like lipid bilayers. A nearly complete (88% of the amino acid residues) backbone and side-chain 13C and 15 N chemical shift assignments of Vs-SemiSWEET were obtained. The overall secondary structure of Vs-SemiSWEET predicted from the obtained 13C and 15 N chemical shifts is similar to that from X-ray crystallography, with some differences, reflecting the influence of the membrane environments to the structure of membrane proteins.

Progress on SARS-CoV-2 3CLpro Inhibitors: Inspiration from SARS-CoV 3CLpro Peptidomimetics and Small-Molecule Anti-Inflammatory Compounds.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) currently poses a threat to human health. 3C-like proteinase (3CLpro) plays an important role in the viral life cycle. Hence, it is considered an attractive antiviral target protein. Whole-genome sequencing showed that the sequence homology between SARS-CoV-2 3CLpro and SARS-CoV 3CLpro is 96.08%, with high similarity in the substrate-binding region. Thus, assessing peptidomimetic inhibitors of SARS-CoV 3CLpro could accelerate the development of peptidomimetic inhibitors for SARS-CoV-2 3CLpro. Accordingly, we herein discuss progress on SARS-CoV-2 3CLpro peptidomimetic inhibitors. Inflammation plays a major role in the pathophysiological process of COVID-19. Small-molecule compounds targeting 3CLpro with both antiviral and anti-inflammatory effects are also briefly discussed in this paper.

High Miscibility Compatible with Ordered Molecular Packing Enables an Excellent Efficiency of 16.2% in All-Small-Molecule Organic Solar Cells.

In all-small-molecule organic solar cells (ASM-OSCs), a high short-circuit current (Jsc ) usually needs a small phase separation, while a high fill factor (FF) is generally realized in a highly ordered packing system. However, small domain and ordered packing always conflicted each other in ASM-OSCs, leading to a mutually restricted Jsc and FF. In this study, alleviation of the previous dilemma by the strategy of obtaining simultaneous good miscibility and ordered packing through modulating homo- and heteromolecular interactions is proposed. By moving the alkyl-thiolation side chains from the para- to the meta-position in the small-molecule donor, the surface tension and molecular planarity are synchronously enhanced, resulting in compatible properties of good miscibility with acceptor BTP-eC9 and strong self-assembly ability. As a result, an optimized morphology with multi-length-scale domains and highly ordered packing is realized. The device exhibits a long carrier lifetime (39.8 µs) and fast charge collection (15.5 ns). A record efficiency of 16.2% with a high FF of 75.6% and a Jsc of 25.4 mA cm-2 in the ASM-OSCs is obtained. These results demonstrate that the strategy of simultaneously obtaining good miscibility with high crystallinity could be an efficient photovoltaic material design principle for high-performance ASM-OSCs.

Peculiar Steric Hindrance Assists Monoclinic Phase Formation toward High-Quality All-Inorganic Perovskites.

Bromine-containing metal halide all-inorganic perovskite CsPbI2Br exhibits excellent photoelectric performance and supreme thermal and structural stabilities; it is thus attractive for use as photoabsorbing layers in perovskite solar cells (PSCs). However, when steric hindrance molecules are introduced, the complicated phase transition mechanism and the difficult-to-control crystallization process in CsPbI2Br are not well understood. Here, we introduce a class of sterically hindered cesium naphthenate small molecules to control the crystallization process of CsPbI2Br films. Of interest, a new intermediate monoclinic phase has been discovered which leads to formation of dense and nonporous polycrystalline perovskite films. This phenomenon was also explained by density functional theory. The residues of steric hindrance molecules inside the CsPbI2Br film also improve its stability. We further show that as the ring number of cycloalkanes increases, the hindrance for the crystallization becomes more significant. Thus, by choosing the suitable steric hindrance, the optimal photovoltaic efficiency is 15.45%.

Strongly Reduced Non-Radiative Voltage Losses in Organic Solar Cells Prepared with Sequential Film Deposition.

With nearly 100% yields for mobile charge carriers in organic solar cells (OSCs), the relatively large photovoltage loss (ΔVoc) is a critical barrier limiting the power conversion efficiency of OSCs. Herein, we aim to improve the open-circuit voltage (Voc) in OSCs with non-fullerene acceptors via sequential film deposition (SD). We show that ΔVoc in planar heterojunction (PHJ) devices prepared by the SD method can be appreciably mitigated, leading increases in Voc to 80 mV with regard to the Voc of bulk heterojunction devices. In PHJ OSCs, the energy level of intermolecular charge-transfer states is found to increase with a decrease in the level of aggregation in the solid state. These properties explain the enhanced electroluminescent quantum efficiency and resultant suppression of the voltage losses induced by nonradiative charge recombination and interfacial charge transfer. This work provides a promising strategy for tackling the heavily discussed photovoltage loss in OSCs.

Boosting the Performance of Self-Powered CsPbCl3-Based UV Photodetectors by a Sequential Vapor-Deposition Strategy and Heterojunction Engineering.

All-inorganic CsPbCl3 perovskite in ultraviolet (UV) detection is drawing increasing interest owing to its UV-matchable optical band gap, ultrahigh UV stability, and superior inherent optoelectronic properties. Almost all of the reported CsPbCl3 photodetectors employ CsPbCl3 nano- or microstructures as sensitive components, while CsPbCl3 polycrystalline film-based self-powered photodetectors are rarely studied on account of the terrible precursor solubility. Herein, a novel sequential vapor-deposition technique is demonstrated to fabricate CsPbCl3 polycrystalline film for the first time. High-quality CsPbCl3 films with excellent optical, electronic, and morphological features are obtained. A self-powered photodetector based on the CsPbCl3 film is constructed without any charge transport layer, showing a high UV detection performance. A thin p-type PbS buffer layer is further introduced to passivate the surface defects of the CsPbCl3 layer and decrease the interfacial energy barrier by forming a type-II heterojunction, contributing to a faster hole extraction rate and a suppressed dark current level. The best-performing device achieves an ultrafast response time of 1.92 µs, an ultrahigh on/off ratio of 2.22 × 105, and a responsivity of 0.22 A/W upon 375 nm UV illumination at 0 V bias. This comprehensive performance is the best among all of the CsPbCl3 photodetectors reported to date. The as-prepared photodetectors also present an eminent UV irradiation and long-term durability in ambient air. Furthermore, a large-area and uniform 625-pixel UV image sensor is fabricated and attains a prominent imaging capability. Our work opens a new avenue for the scalable production of CsPbCl3-based optoelectronics.

Broadening the Spectral Response of Perovskite Photodetector to the Solar-Blind Ultraviolet Region through Phosphor Encapsulation.

Hybrid perovskite photodetectors generally exhibit brilliant performance for photodetecting in the visible spectrum but poor detectability in the solar-blind ultraviolet (UV) region. To break through the bottleneck, we demonstrate a novel strategy to broaden the spectral response of perovskite photodetectors to the solar-blind UV region through phosphor encapsulation. The high photoluminescence quantum yield trichromatic phosphor capping layer achieves an extended spectral response to the solar-blind UV region through effectively down-converting the incident UV light into visible light. In addition, an external quantum efficiency of up to 12.13%@265 nm is achieved without bias voltage, while the initial value is near zero. The corresponding spectral responsivity and detectivity are 0.0269 A/W and 7.52 × 1011 Jones, respectively. Thus, the photodetectors show a high photocurrent and on/off ratio, increasing by roughly 2 orders of magnitude. Moreover, the photodetectors exhibit a large linear dynamic range of 105 dB, fast response times of 50.16/51.99 µs, and excellent stability. The practical applications for flame detection and UV-based communication are further explored. This work provides a new way to achieve UV light detection based on perovskite photodetectors. Perhaps, it may also be a promising alternative for wide-band gap semiconductors to realize the urgent pursuit of UV detection.