Infiltrated 2D/3D Heterojunction with Tunable Electric Field Landscape for Robust Inverted Perovskite Solar Cells with over 24% Efficiency.

In inverted perovskite solar cells, conventional planar 2D/3D perovskite heterojunctions typically exhibit a type-II band alignment, where the electric field tends to drive the electron motion in the opposite direction to the direction of electron transfer. Here, a 2D/3D gradient heterojunction is developed by allowing the 2D perovskite to infiltrate the 3D perovskite surface along the grain boundaries using the interaction between the organic cation of the 2D perovskite and the pseudohalogen thiocyanate ion (SCN-), which has the ability to diffuse downward. The infiltrated 2D perovskite not only fills the gaps of grain boundaries with improved structural stability, but it also reconstructs the original landscape of the electric field toward the n-doped surface to enable more rapid electron transfer and weaken the adverse type-II band alignment effect. Since 2D perovskite seals the GBs, the nonvolatile SCN- can accumulate at the top and bottom dual interfaces, releasing residual stress and significantly inhibiting nonradiative recombination. The device exhibits an excellent efficiency of 24.76% (certified 24.29%) and long-term stability that is >90% of the original PCE value after 800 h of heating at 85 °C or in high humidity (≈65%).

Inhibiting Interfacial Diffusion in Heterojunction Perovskite Solar Cells by Replacing Low-Dimensional Perovskite with Uniformly Anchored Quaternized Polystyrene.

Surface heterojunction has been regarded as an effective method to improve the device efficiency of perovskite solar cells. Nevertheless, the durability of different heterojunction under thermal stress is rarely investigated and compared. In this work, benzylammonium chloride and benzyltrimethylammonium chloride are utilized to construct 3D/2D and 3D/1D heterojunctions, respectively. A quaternized polystyrene is synthesized to construct a three-dimensional perovskite/amorphous ionic polymer (3D/AIP) heterojunction. Due to the migration and volatility of organic cations, severe interfacial diffusion is found among 3D/2D and 3D/1D heterojunctions, in which the quaternary ammonium cations in the 1D structure are less volatile and mobile than the primary ammonium cations in the 2D structure. 3D/AIP heterojunction remains intact under thermal stress due to the strong ionic bond anchoring at the interface and the ultra-high molecular weight of AIP. Furthermore, the dipole layer formed by AIP can further reduce the voltage loss caused by nonradiative recombination at the interface by 0.088 V. Therefore, the devices based on the 3D/AIP heterojunction achieve a champion power conversion efficiency of 24.27% and maintain 90% of its initial efficiency after either thermal aging for 400 h or wet aging for 3000 h, showing a great promise for polymer/perovskite heterojunction towards real applications.

Organizing Uniform Phase Distribution in Methylammonium-Free 1.77 eV Wide-Bandgap Inverted Perovskite Solar Cells.

Disordered crystallization and poor phase stability of mixed halide perovskite films are still the main factors that compromise the performance of inverted wide bandgap (WBG; 1.77 eV) perovskite solar cells (PSCs). Great difficulties are evidenced due to the very different crystallization rates between I- and Br-based perovskite components through DMSO-alone assisted anti-solvent process. Here, a zwitterionic additive strategy is reported for finely regulating the crystal growth of Cs0.2 FA0.8 Pb(I0.6 Br0.4 )3 , thereby obtaining high-performance PSCs. The aminoethanesulfonic acid (AESA) is introduced to form hydrogen bonds and strong PbO bonds with perovskite precursors, realizing the complete coordination with both the organic (FAI) and inorganic (CsI, PbI2 , PbBr2 ) components, balancing their complexation effects, and realizing AESA-guided fast nucleation and retarded crystallization processes. This treatment substantially promotes homogeneous crystal growth of I- and Br-based perovskite components. Besides, this uniformly distributed AESA passivates the defects and inhibits the photo-induced halide segregation effectively. This strategy generates a record efficiency of 19.66%, with a Voc of 1.25 V and FF of 83.7% for an MA-free WBG p-i-n device at 1.77 eV. The unencapsulated devices display impressive humidity stability at 30 ± 5% RH for 1000 h and much improved continuous operation stability at MPP for 300 h.

Structural Fusion Yields Guest Acceptors that Enable Ternary Organic Solar Cells with 18.77 % Efficiency.

The design and selection of a suitable guest acceptor are particularly important for improving the photovoltaic performance of ternary organic solar cells (OSCs). Herein, we designed and successfully synthesized two asymmetric silicon-oxygen bridged guest acceptors, which featured distinct blue-shifted absorption, upshifted lowest unoccupied molecular orbital energy levels, and larger dipole moments than symmetric silicon-oxygen-bridged acceptor. Ternary devices with the incorporation of 14.2 wt % these two asymmetric guest acceptors exhibited excellent performance with power conversion efficiencies (PCEs) of 18.22 % and 18.77 %, respectively. Our success in precise control of material properties via structural fusion of five-membered carbon linkages and six-membered silicon-oxygen connection at the central electron-donating core unit of fused-ring electron acceptors can attract considerable attention and bring new vigor and vitality for developing new materials toward more efficient OSCs.

Surface-Anchored Acetylcholine Regulates Band-Edge States and Suppresses Ion Migration in a 21%-Efficient Quadruple-Cation Perovskite Solar Cell.

Although incorporating multiple halogen (bromine) anions and alkali (rubidium) cations can improve the open-circuit voltage (Voc ) of perovskite solar cells (PSCs), severe voltage loss and poor stability have remained pivotal limitations to their further commercialization. In this study, acetylcholine (ACh+ ) is anchored to the surface of a quadruple-cation perovskite to provide additional electron states near the valence band maximum of the perovskite surface, thereby enhancing the band alignment and minimizing the Voc loss significantly. Moreover, the quaternary ammonium and carbonyl units of ACh+ passivate the antisite and vacancy defects of the organic/inorganic hybrid perovskite. Because of strong interactions between ACh+ and the perovskite, the formation of lead clusters and the migration of halogen anions in the perovskite film are suppressed. As a result, the device prepared with ACh+ post-treatment delivers a power conversion efficiency (PCE) (21.56%) and a value of Voc (1.21 V) that are much higher than those of the pristine device, along with a twofold decrease in the hysteresis index. After storage for 720 h in humid air, the device subjected to ACh+ treatment maintained 70% of its initial PCE. Thus, post-treatment with ACh+ appears to be a useful strategy for preparing efficient and stable PSCs.

Bottom-Up Templated and Oriented Crystallization for Inverted Triple-Cation Perovskite Solar Cells with Stabilized Nickel-Oxide Interface.

Inverted-structure perovskite solar cells (PSCs) are known for their superior device stability. However, based on nickel-oxide (NiOx ) substrate, disordered crystallization and bottom interface instability of perovskite film are still the main factors that compromise the power conversion efficiency (PCE) of PSCs. Here, 2D perovskite of thiomorpholine 1,1-dioxide lead iodide (Td2 PbI4 ) is introduced as a template to prepare 3D perovskite thin film with high crystal orientation and large grain size via a bottom-up growth method. By adding TdCl to the precursor solution, pre-crystallized 2D Td2 PbI4 seeds can accumulate at the bottom interface, lowering the barrier of nucleation, and templating the growth of 3D perovskite films with improved (100) orientation and reduced defects during crystallization. In addition, 2D Td2 PbI4 at the bottom interface also hinders the interfacial redox reaction and reduces the hole extraction barrier on the buried interface. Based on this, the Td-0.5 PSC achieves a PCE of 22.09% and an open-circuit voltage of 1.16 V. Moreover, Td-0.5 PSCs show extremely high stability, which retains 84% of its initial PCE after 500 h of continuous illumination under maximum power point operating conditions in N2 atmosphere. This work paves the way for performance improvement of inverted PSCs on NiOx substrate.

Centimeter-Sized Single Crystal of Two-Dimensional Halide Perovskites Incorporating Straight-Chain Symmetric Diammonium Ion for X-Ray Detection.

Two-dimensional (2D) AA'n-1 Mn X3n+1 type halide perovskites incorporating straight-chain symmetric diammonium cations define a new type of structure, but their optoelectronic properties are largely unexplored. Reported here is the synthesis of a centimeter-sized AA'n-1 Mn X3n+1 type perovskite, BDAPbI4 (BDA=NH3 C4 H8 NH3 ), single crystal and its charge-transport properties under X-ray excitation. The crystal shows a staggered configuration of the [PbI6 ]4- layers, a band gap of 2.37 eV, and a low trap density of 3.1×109  cm-3 . The single-crystal X-ray detector exhibits an excellent sensitivity of 242 µC Gyair -1 cm-2 under the 10 V bias (0.31 V µm-1 ), a detection limit as low as 430 nGyair s-1 , ultrastable response current, a stable baseline with the lowest dark current drift of 6.06×10-9  nA cm-1 s-1 V-1 , and rapid response time of τrise =7.3 ms and τfall =22.5 ms. These crystals are promising candidates for the next generation of optoelectronic devices.

Epinephrine-modified methacrylate monolithic column with fumed silica nanoparticle for pressurized capillary electrochromatography.

Via the ring-opening reaction of epoxy groups with epinephrine, a novel epinephrine functionalized polymethacrylate monolith with fumed silica nanoparticles has been fabricated for pressurized capillary electrochromatography. The preparation of epinephrine-modified monoliths has been optimized. In addition, morphology, electroosmotic flow, separation mechanism and column performance have been studied. The internal structure of the monolithic stationary phase was more uniform and the column efficiency increased after the incorporation of nanoparticles. With this column, satisfactory separation capability of aromatic compounds and alkaloids has been achieved and the column efficiency for naphthalene reached 138 696 plates/m. As for the real sample, 3 alkaloids were separated in Huanglian Shangqing capsules, a Chinese traditional medicine.

Preparation of a capillary isoelectric focusing column with monolithic immobilized pH gradient and its application on protein separation based on an online capillary isoelectric focusing platform.

In the presence of methanol and n-decanol as porogens, a partially filled capillary monolithic column was prepared by in situ reaction of glycidyl methacrylate and poly (ethylene glycol) diacrylate. Then, Pharmalyte 3-10 was immobilized on this column in order to obtain a capillary isoelectric focusing (cIEF) column with monolithic immobilized pH gradient (M-IPG). In addition, an online self-built platform for protein separation was established on account of the introduction of a cross-shaped unit and two short-off valves. In this platform, a cross-shaped unit was not only used to join the M-IPG column and a six-way injection valve (1.5 µL sample loop), but also to supply a volume pool of anode buffer so that the process of injection, focusing and mobilization of samples could be sequentially performed. The short-off valve in the tee unit or cross-shaped unit could be used to control the direction of the fluid flow. Using this online cIEF platform and under the optimized conditions, 7-proteins mixture could be separated and a good linear correlation between pI values and migration times was obtained by the M-IPG column. Meanwhile, based on the online cIEF platform, human serum proteins and a mixture of Hb A and Hb A1c have been successfully resolved with the newly developed M-IPG column.

Investigating the nature of graphene-based films prepared by vacuum filtration of graphene dispersions.

Though the graphene-based films prepared by vacuum filtration of graphene dispersions can be well and easily prepared so far and show great prospects in conductive, transparent, and flexible devices and coatings, the nature of these films has been rarely investigated. In order to reveal how graphene flakes constitute these films, herein we prepared a thin graphene-based film by vacuum filtering graphene dispersions and characterized the film by diverse techniques. Microscopic analyses evidenced the layer structure nature of the film. Raman spectra, transmission electron microscopy, and X-ray diffraction results indicate that the film is neither graphene nor graphite, but intrinsically a graphene block constituted by numerous graphene flakes which are randomly stacked. Though aggregation of graphene flakes happens in the filtration process, the aggregation is not a process to drive graphene flakes stacked in Bernal AB style to form bulk graphite. The adjoining graphene flakes are poorly coupled, likely due to the interlayer adventitious impurities introduced from liquid-phase processing.

Screening and evaluation of bamboo shoots: Comparing the content of trace elements from 100 species.

Hundreds of bamboo shoots have been reported to be edible, but the accumulation of trace elements and hazardous elements in bamboo shoots is poorly understood. Here, 100 bamboo species have been evaluated by screening elements including B, Fe, Mn, Cu, Zn, Cd, Pb and As in bamboo shoots using different assessment systems. Bamboo shoots displayed different morphological characteristics, and large differences were found in the concentration of elements. Most bamboo shoots were rich in Fe and Zn and low concentrations of hazardous elements, but the concentration of Cd and Pb exceeded the maximum permissible limits of tuber vegetables in some bamboo species. Different bamboo shoots were ranked differently in the four assessment systems, and the comprehensive evaluation assigned final scores to all 100 bamboo shoots. This study provides valuable recommendations for selecting high-quality bamboo shoots that are rich in trace elements nutrition while minimizing the potential for hazardous element accumulation.

Minimizing Interfacial Energy Loss and Volatilization of Formamidinium via Polymer-Assisted D-A supramolecular Self-Assembly Interface for Inverted Perovskite Solar Cells with 25.78% Efficiency.

2D perovskite passivation strategies effectively reduce defect-assisted carrier nonradiative recombination losses on the perovskite surface. Nonetheless, severe energy losses are causing by carrier thermalization, interfacial nonradiative recombination, and conduction band offset still persist at heterojunction perovskite/PCBM interfaces, which limits further performance enhancement of inverted heterojunction PSCs. Here, 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (5FTPP) is introduced between 3D/2D perovskite heterojunction and PCBM. Compared to tetraphenylporphyrin without electron-withdrawing fluoro-substituents, 5FTPP can self-assemble with PCBM at interface into donor-acceptor (D-A) complex with stronger supramolecular interaction and lower energy transfer losses. This rapid energy transfer from donor (5FTPP) to acceptor (PCBM) within femtosecond scale is demonstrated to enlarge hot carrier extraction rates and ranges, reducing thermalization losses. Furthermore, the incorporation of polystyrene derivative (PD) reinforces D-A interaction by inhibiting self-π-π stacking of 5FTPP, while fine-tuning conduction band offset and suppressing interfacial nonradiative recombination via Schottky barrier, dipole, and n-doping. Notably, the multidentate anchoring of PD-5FTPP with FA+, Pb2+, and I- mitigates the adverse effects of FA+ volatilization during thermal stress. Ultimately, devices with PD-5FTPP achieve a power conversion efficiency of 25.78% (certified: 25.36%), maintaining over 90% of initial efficiency after 1000 h of continuous illumination at the maximum power point (65 °C) under ISOS-L-2 protocol.

Efficient Charge Transport in Inverted Perovskite Solar Cells via 2D/3D Ferroelectric Heterojunction.

While the 2D/3D heterojunction is an effective method to improve the power conversion efficiency (PCE) of perovskite solar cells (PSCs), carriers are often confined in the quantum wells (QWs) due to the unique structure of 2D perovskite, which makes the charge transport along the out-of-plane direction difficult. Here, a 2D/3D ferroelectric heterojunction formed by 4,4-difluoropiperidine hydrochloride (2FPD) in inverted PSCs is reported. The enriched 2D perovskite (2FPD)2PbI4 layer with n = 1 on the perovskite surface exhibits ferroelectric response and has oriented dipoles along the out-of-plane direction. The ferroelectricity of the oriented dipole layer facilitates the enhancement of the built-in electric field (1.06 V) and the delay of the cooling process of hot carriers, reflected in the high carrier temperature (above 1400 K) and the prolonged photobleach recovery time (139.85 fs, measured at bandgap), improving the out-of-plane conductivity. In addition, the alignment of energy levels is optimized and exciton binding energy (32.8 meV) is reduced by changing the dielectric environment of the surface. Finally, the 2FPD-treated PSCs achieve a PCE of 24.82% (certified: 24.38%) with the synergistic effect of ferroelectricity and defect passivation, while maintaining over 90% of their initial efficiency after 1000 h of maximum power point tracking.

Correlation of carotenoid accumulation with aggregation and biofilm development in Rhodococcus sp. SD-74.

Aggregation of bacterial populations substantially influences their characteristic properties and functions compared with the planktonic counterpart. It is also involved in the initial stages of biofilm development. Many studies have revealed important roles of bacterial aggregation in microbial production and biodegradation. Nevertheless, mechanistic understanding of bacterial aggregation in vivo and at the molecular level is far from complete. Here, we present a noninvasive, label-free Raman microspectroscopic approach to investigate the aggregation and biofilm development of the biotechnologically important Rhodococcus sp. SD-74. We found that the concentration of intracellular carotenoids increases more than 3-fold within 1 week as the biofilm develops. Raman imaging experiments confirmed that the carotenoid accumulation occurs throughout the Rhodococcus sp. SD-74 biofilm. The correlation between the carotenoid Raman intensities and biofilm development found in the present study provides a new means for quantitative, molecular-level assessment of the level of biofilm development, which is not possible with dye staining assay or electron microscopy. Moreover, our results suggest that microbial production of carotenoids in pigmented bacteria such as Rhodococcus sp. SD-74 may potentially be controlled via bacterial aggregation and biofilm formation.

Targeting Annexin A1 as a Druggable Player to Enhance the Anti-Tumor Role of Honokiol in Colon Cancer through Autophagic Pathway.

Colon cancer is one of the most common digestive tract malignancies, having the second highest mortality rate among all tumors, with a five-year survival of advanced patients of only 10%. Efficient, targeted drugs are still lacking in treating colon cancer, so it is urgent to explore novel druggable targets. Here, we demonstrated that annexin A1 (ANXA1) was overexpressed in tumors of 50% of colon cancer patients, and ANXA1 overexpression was significantly negatively correlated with the poor prognosis of colon cancer. ANXA1 promoted the abnormal proliferation of colon cancer cells in vitro and in vivo by regulating the cell cycle, while the knockdown of ANXA1 almost totally inhibited the growth of colon cancer cells in vivo. Furthermore, ANXA1 antagonized the autophagic death of honokiol in colon cancer cells via stabilizing mitochondrial reactive oxygen species. Based on these results, we speculated that ANXA1 might be a druggable target to control colon cancer and overcome drug resistance.

Green-solvent-processed formamidinium-based perovskite solar cells with uniform grain growth and strengthened interfacial contact via a nanostructured tin oxide layer.

Green-solvent-processed perovskite solar cells (PSCs) have reached an efficiency of 20%, showing great promise in safe industrial production. However, the nucleation process in green-solvent-based deposition is rarely optimized, resulting in randomized crystallization and much lowered reported efficiencies. Herein, a nanostructured tin oxide nanorods (SnO2-NRs) substrate is utilized to prepare a high-quality formamidinium (FA)-based perovskite film processed from a green solvent of triethyl phosphate (TEP) with a low toxic antisolvent of dibutyl ether (DEE). Compared with SnO2 nanoparticles, the oriented SnO2-NRs can accelerate the formation of heterogeneous nucleation sites and retard the crystal growth process of the perovskite film, resulting in a high-quality perovskite film with uniform grain growth. Furthermore, a chlorine-terminated bifunctional supramolecule (Cl-BSM) is introduced to passivate the increasing interfacial defects due to the vast contact area in SnO2-NRs. Correspondingly, the substrate design of SnO2-NRs with Cl-BSM increases the power conversion efficiency (PCE) of green-solvent-processed PSCs to 22.42% with an open-circuit voltage improvement from 1.02 to 1.12 V, which can be attributed to the uniform grain growth and reduced carrier recombination at the SnO2-NRs/perovskite interface. More importantly, the photo and humidity stabilities of the unencapsulated device for up to 500 and 1000 hours are also achieved with negligible interfacial delamination after aging. This work provides a new perspective on the future industrial scale production of PSCs using environment-friendly solvents with compatible substrate design.

Attenuated Salmonella carrying siRNA-CD24 improved the effect of oxaliplatin on HCC.

Oxaliplatin is a chemotherapy drug currently utilized in the treatment of advanced cancer patients. However, its tolerability poses a limitation to its clinical application. Studies have demonstrated that the presence of tumor-associated macrophages is positively correlated with poor prognosis in various solid tumors, including hepatocellular carcinoma (HCC), and is a significant factor contributing to oxaliplatin resistance. Therefore, targeting tumor-associated macrophages may be an effective strategy to improve the efficacy of oxaliplatin in the treatment of HCC patients. CD24 is a novel target for tumor therapy that can interact with the inhibitory receptor Siglec-10 on tumor-associated macrophages, transmitting immune inhibitory signals and inhibiting macrophage phagocytosis function. In this study, we utilized RNAi technology to inhibit the expression of CD24 in tumor cells and combined it with oxaliplatin, resulting in reduced tumor invasion, migration, and proliferation, as well as increased cell apoptosis. Furthermore, immunofluorescence and flow cytometry results indicated that both the single treatment group and combination treatment group enhanced the infiltration of immune cells. This study presents a novel approach to identifying combination therapy and targets for the clinical treatment of HCC with oxaliplatin.

In situ dipole formation to achieve high open-circuit voltage in inverted perovskite solar cells via fluorinated pseudohalide engineering.

Many studies have shown that the severe photoluminescence quantum yield (PLQY) loss at the interface between the perovskite and electron transport layer (ETL) is the main cause of voltage loss in inverted perovskite solar cells (p-i-n PSCs). However, currently there are no effective in situ passivation techniques to minimize this nonradiative recombination. Here, the fluorinated pseudohalide ionic liquid (FPH-IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI) is introduced into the perovskite precursor formulation. EMIMTFSI can change the dielectric environment and energy-level arrangement of the perovskite by accumulating on the top surface and spontaneously forming dipoles. As a result, the excitonic binding energy (Eb) and nonradiative recombination loss are significantly reduced. At the same time, TFSI- reduces the formation energy of vacancy defects and stabilizes the perovskite phase by forming N-H⋯F hydrogen bonds between FA+ and the C-F bond in EMIMTFSI. Finally, the EMIMTFSI-modified p-i-n PSCs achieve an excellent efficiency of 24.81% with an impressive open-circuit voltage of 1.191 V for a 1.57 eV low-bandgap perovskite. In addition, the modified devices can maintain more than 95% PCE after continuous thermal aging at 85 °C for 500 h or illumination at the maximum power point for 800 h. This work provides a new idea for minimizing the non-radiative recombination losses in p-i-n PSCs.

Shrinkable Hydrogel-Enhanced Biomarker Detection with X-ray Fluorescent Nanoparticles.

This paper reports a new method to enhance the sensitivity of nanoparticle-based protein detection with X-ray fluorescence by exploiting the large volume reduction of hydrogel upon dehydration. A carboxylated agarose hydrogel with uniaxial microchannels is used to allow rapid diffusion of nanoparticles and biomolecules into the hydrogel and water molecules out of the hydrogel. Carboxylated hydrogels are modified to capture protein biomarkers and X-ray fluorescence nanoparticles (iron oxide nanoparticles) are modified with antibodies that are specific to protein biomarkers. The presence of protein biomarkers in solution binds the nanoparticles on the hydrogel channels. The dehydration of hydrogels leads to a size reduction of over 80 times, which increases the number of nanoparticles in the interaction volume of the primary X-ray beam and the intensity of characteristic X-ray fluorescence signal. A detection limit of 2 µg/mL for protein detection has been established by determining the number of nanoparticles using X-ray fluorescence.

Electrochemical oxidative rearrangement of tetrahydro-ß-carbolines in a zero-gap flow cell.

Oxidative rearrangement of tetrahydro-ß-carbolines (THßCs) is one of the most efficient methods for the synthesis of biologically active spirooxindoles, including natural products and drug molecules. Here, we report the first electrochemical approach to achieve this important organic transformation in a flow cell. The key to the high efficiency was the use of a multifunctional LiBr electrolyte, where the bromide (Br-) ion acts as a mediator and catalyst and lithium ion (Li+) acts as a likely hydrophilic spectator, which might considerably reduce diffusion of THßCs into the double layer and thus prevent possible nonselective electrode oxidation of indoles. Additionally, we build a zero-gap flow cell to speed up mass transport and minimize concentration polarization, simultaneously achieving a high faradaic efficiency (FE) of 96% and an outstanding productivity of 0.144 mmol (h-1 cm-2). This electrochemical method is demonstrated with twenty substrates, offering a general, green path towards bioactive spirooxindoles without using hazardous oxidants.