Smooth Surface Morphology Research Articles

Effect of 3D-Printed Polycaprolactone Scaffold With Powdery/Smooth Micromorphology on Local Immune Environments.

Selective laser sintering (SLS) has become a viable approach for producing biodegradable medical implants in various clinical applications. The resulting scaffolds typically exhibit a powdery microstructure, which may potentially impact the behavior of immune cells and immune responses in surrounding tissues. However, limited research has been conducted to understand the effect of surface morphology in SLS-fabricated scaffolds on local immune environments. This study aims to compare the effect of SLS-fabricated polycaprolactone (PCL) scaffolds with powdery and smooth surface morphologies on immune-related biological responses. Compared with those on the powdery micromorphology, RAW264.7 macrophages displayed greater dispersion and adopted a spread and elongated morphology on the scaffolds with smooth surface. The expression levels of arginase-1 and CD206 were found to be upregulated in macrophages adhering to the PCL scaffolds with smooth surface, accompanied by an augmented secretion of anti-inflammatory cytokines TGF-β and IL-10. Conversely, there was a decrease in the secretion of pro-inflammatory cytokines TNF-α and IL-12. When implanted invivo, the SLS-derived scaffolds were completely covered by host tissues, Withing increased collagen deposition, indicating good histocompatibility. At 1-week post-implantation, there was a significantly higher presence of M2-type macrophages surrounding the scaffold compared to M1 macrophages in both groups. By 3 weeks post-implantation, the overall level of macrophages had decreased in both groups. However, a significant higher level of M1 macrophages were observed in the powdery scaffold group. At the same time, the number of neutrophils around the powder scaffold increased significantly, demonstrating long-term local inflammatory responses. The results suggested that post-treated scaffolds with smooth surfaces can effectively reduce local inflammation, making them more suitable for clinical implantation.

Organic-Inorganic Hybrid One-Dimensional Photonic Crystals with Blue and NIR Dual Bandgaps for Light Protection.

Planar 1D photonic crystals (1DPhCs), owing to their photonic bandgaps (PBGs) formed by unique structural interference, are widely utilized in light protection applications. Multifunctional coatings that integrate various light management functions are highly desired. In this study, we present the fabrication of dual-PBG 1DPhCs with high reflectance in both the blue and near-infrared (NIR) regions. The 1DPhCs were constructed through the alternating stacking of hollow SiO2 (HS) nanoparticles hybridized with poly(vinyl alcohol) (PVA), referred to as PHS, and TiO2 layers. The 1DPhC with 7 bilayers demonstrated remarkable reflectance of 98.2% and 93.4% in the blue and NIR spectra, respectively, with shielding efficiencies of 93.9% and 85.6%. Compared to bare PC, the temperature was observed to be 10.6 °C lower, achieving a thermal insulation efficiency of 44.8% in the 900 nm near-infrared range. Additionally, spectral fitting using the transfer matrix method (TMM) and optimization of process parameters, including PHS concentration and spin-coating speed, enabled the fabrication of 1DPhCs with tunable optical thickness ratios. The fabricated films demonstrated a smooth surface morphology with flat and uniform interfaces, as well as excellent environmental stability. These features make the 1DPhCs highly promising for applications in light protection and thermal management. This study provides a novel approach for the development of dual-PBG 1DPhCs with enhanced protective capabilities.

Enhanced targeted treatment of cervical cancer using nanoparticle-based doxycycline delivery system

This study investigates a nanoparticle-based doxycycline (DOX) delivery system targeting cervical cancer cells via the CD44 receptor. Molecular docking revealed a strong binding affinity between hyaluronic acid (HA) and CD44 (binding energy: -7.2 kJ/mol). Characterization of the HA-Chitosan nanoparticles showed a particle size of 284.6 nm, a zeta potential of 16.9 mV, and a polydispersity index of 0.314, with SEM confirming smooth surface morphology. The encapsulation efficiency of DOX-loaded nanoparticles was 89.32%, exhibiting a sustained release profile, with 67.45% released over 72 h in acidic conditions (pH 5.5). Cytotoxicity assays demonstrated a significant reduction in HeLa cell viability to 22% at 72 h, compared to 67% in normal HEK cells. Stability tests confirmed the maintenance of nanoparticle integrity and a consistent drug release profile over three months. Cell migration was reduced by 45%, and RT-PCR analysis revealed a 53% downregulation of TNF-α expression, suggesting effective targeting of inflammatory pathways. These results underscore the potential of HA-Chitosan-based DOX nanoparticles in improving cervical cancer treatment through enhanced targeted delivery and inhibition of tumor-promoting mechanisms.

Nonpolar P-type Conjugated Small Molecules Enable High-Performance Organic Photodetectors for Potential Application in Optical Wireless Communication.

The high responsivity and broad spectral sensitivity of organic photodetectors (OPDs) present a bright future of commercialization. However, the relatively high dark current density still limits its development. Herein, two novel nonpolar p-type conjugated small molecules, NSN and NSSN, are synthesized as interface layers to enhance the performance of the OPDs, which not only can tune energy alignments and increase the reverse charge injection barrier but also can reduce the interfacial trap density. Moreover, benefiting from the smoother surface morphology and enhanced conductivity, the NSN exhibited superior charge transport and collection properties. Consequently, the OPD with NSN achieved a dark current density of 0.37 nA cm-2 and a high specific detectivity of 2.77 × 1013 Jones at -2 V. More importantly, the optimized OPDs can be successfully integrated into optical communication systems, demonstrating precise digital signal communication without obvious distortion, showing promising application potential in the wireless transmission system.

Atomic layer deposition of Sn-doped germanium diselenide for an As-free Ovonic threshold switch with low off-current.

This work introduces the atomic layer deposition (ALD) of Sn-doped GeSe2 (SnGS2) films for developing arsenic-free Ovonic threshold switch (OTS) devices with low off-current (Ioff) and desirable threshold voltage (Vt). The undoped GeSe2 film exhibits high Vt and low endurance characteristics despite its low Ioff originating from a large mobility gap. Such problems could be overcome by appropriate doping, and thus, Sn was doped into the GeSe2 film using a supercycle consisting of SnNx and GeSe2 subcycles. The co-injection of NH3 with Se-precursor ([(CH3)3Si]2Se) during the GeSe2 subcycle generated a reactive H2Se intermediate, which enhanced the reactivity and transformed the pre-deposited SnNx to SnSe2. The overall cation-to-anion ratio of the deposited films remained at approximately 1 : 2, with amorphous structure and smooth surface morphology. The planar OTS device using SnGS2 films with a Sn concentration of 9.6%, for which the crystallization temperature was >400 °C, showed the lowest Vt of ∼3.5 V and Ioff of ∼12.5 nA at half Vt and demonstrated switching endurance over 106 cycles. Furthermore, a vertical-type OTS device was fabricated using the same SnGS2 film using the excellent step coverage of ALD, exhibiting similar switching characteristics to its planar counterpart.

Characterizations of rice husk based silica made from acid leaching extraction method

Rice husk is a material that is greatly acquired through agriculture, which opens up as a source for silica. It available in high quantity that has potential to be used in the concrete. Consequently, this research aims to address this gap by extracting and characterizing the silica from rice husks using the acid leaching method. The different leaching duration of for 6, 12, 18, and 24 hours is the main point of focus in this research. Leaching was done using 0.1 M HCl at room temperature. The XRD, EDX, and SEM are used to characterize the silica. The outcome has been achieved for leaching a period of 24 hour at room temperature was optimal for producing amorphous silica with minimal crystalline and smoothest surface morphology. The study explores an energy efficient and mass production method for silica extraction from rice husks.

Formulation, Development, and Characterization of AMB-Based Subcutaneous Implants using PCL and PLGA via Hot-Melt Extrusion

The hot-melt extrusion process is currently considered a prominent manufacturing technique in the pharmaceutical industry. The present study is intended to develop amlodipine besylate (AMB)-loaded subcutaneous implants to reduce the frequency of administration, thus improving patient compliance during hypertension management. AMB subcutaneous implants were prepared using continuous hot-melt extrusion technology using poly(caprolactone) and poly(lactic-co-glycolic acid) with dimensions of 3.70 cm (length) by 2.00 mm (diameter). The implants were characterized for thermal characteristics, drug-excipient incompatibilities, surface morphology, fracturability, in vitro drug release, and stability studies. Differential scanning calorimetry study confirmed the drug's crystalline state within the fabricated implants, while textural analysis demonstrated good fracturability in the lead formulation. Scanning electron microscopy revealed the smooth surface morphology of the lead subcutaneous implant. The lead formulation showed an extended drug release profile over 30 days (~ 2.25 mg per day) and followed zero-order release kinetics (R2 value to 0.9999) with a mean dissolution time of 14.96 days. The lead formulation remained stable for 30 days at accelerated stability conditions of 40°C and 75% relative humidity. In conclusion, developing hot-melt extruded implants could be an alternative to the conventional amlodipine besylate (AMB) formulation.Graphical

Nano-spherical tip-based smoothing with minimal damage for 2D van der Waals heterostructures.

Two-dimensional materials and their heterostructures have significant potential for future developments in materials science and optoelectronics due to their unique properties. However, their fabrication and transfer process often introduce impurities and contaminants that degrade their intrinsic qualities. To address this issue, current atomic force microscopy (AFM) probe contact mode methods provide a solution by allowing in situ cleaning and real-time observation of the nanoscale cleaning process. Nevertheless, existing pyramidal probes may scratch surfaces and damage heterostructures during force application. Therefore, we proposed a method based on the nano-spherical probe contact mode to clean residual and polymer contamination for minimum damage cleaning of MoS2/hBN substrates. Comparative experiments with pyramidal probes in 2DM morphology and photoluminescence (PL) have shown that nano-spherical probes are exceptionally effective in cleaning bubbles of various sizes, compared to uncleaned MoS2, where PL full width at half maximum (FWHM) averages 0.115 eV, nano-spherical probes reduce it by 30% to 0.08 eV. Pyramidal probes, however, only clean smaller bubbles and leave residuals in larger ones, resulting in less optimal PL mapping data with values in both the 0.09 eV and 0.0115 eV regions. We also collected the standard deviation of the FWHM data points for the uncleaned region and the regions cleaned by the pyramidal and nano-spherical probes, which were 0.02773, 0.01895, and 0.00531, respectively. Notably, the standard deviation of the FWHM in the nano-spherical probe-cleaned region is only 28% of that in the pyramidal probe-cleaned region. Then, increasing the applied force leads to damage in the crystal structure, resulting in potential inconsistencies across different areas, as evidenced by KPFM and SEM observations. In contrast, nano-spherical probes demonstrate a uniform potential in KPFM and consistently maintain a smooth surface morphology in SEM throughout the process. This approach highlights the potential of nano-spherical probes to advance minimum-damage cleaning techniques in 2D material research and applications.

In situ etching of β-Ga2O3 using tert-butyl chloride in an MOCVD system

In this study, we investigate in situ etching of β-Ga2O3 in a metalorganic chemical vapor deposition system using tert-butyl chloride (TBCl). We report etching of both heteroepitaxial 2¯01-oriented and homoepitaxial (010)-oriented β-Ga2O3 films over a wide range of substrate temperatures, TBCl molar flows, and reactor pressures. We infer that the likely etchant is HCl (g), formed by the pyrolysis of TBCl in the hydrodynamic boundary layer above the substrate. The temperature dependence of the etch rate reveals two distinct regimes characterized by markedly different apparent activation energies. The extracted apparent activation energies suggest that at temperatures below ∼800 °C, the etch rate is likely limited by desorption of etch products. The relative etch rates of heteroepitaxial 2¯01 and homoepitaxial (010) β-Ga2O3 were observed to scale by the ratio of the surface energies, indicating an anisotropic etch. Relatively smooth post-etch surface morphology was achieved by tuning the etching parameters for (010) homoepitaxial films.

Chitosan: Microsphere Formulation and Characterization for Slow - release Prebiotic Activities in Gut Microbiota Remodelling.

Chitosan is a biocompatible, mucoadhesive, and biodegradable polymer widely used for various purposes due to its biological activity and safety. The current study aimed to formulate Chitosan microspheres and conduct an in-vitro evaluation of their cytotoxicity. The concept is focused on targeted gut delivery and biological activities in gut microbiota remodelling. The formulations were comprehensively characterized, encompassing SEM for surface morphology, particle size analysis, and FT-IR for structural understanding. Along with biological activity and cytotoxicity studies, dissolution efficiency was considered to understand release kinetics potential and accelerated stability studies to predict formulation shelf-life. The formulation showed smooth spherical surface morphology with an average size range of 30.0 ± 5.0 μm and a charge of 20.35 ± 0.35 mV. Further, functional and thermal properties were determined using FT-IR and DSC, respectively. The microspheres showed a potent prebiotic potential in gut flora isolated and processed from a faecal sample of Wistar rats with prolonged release characteristics in the dissolution study. A cytotoxicity study using rat intestinal epithelial cells (IEC6) indicated that 40 mg /kg of microspheres could be considered an optimal dose for an in-vivo study. The formulation demonstrated promising pharmaceutical applicability due to its potential prebiotic nature and slow release into the gut environment. After a thorough in vivo study, the microspheres can be broadly used to restore gut dysbiosis due to their potential prebiotic activities in various diseases and disorders, including but not limited to obesity, type-2 diabetes, cardiometabolic disease, and non-alcoholic fatty liver disease.

Effects of Different Plasticizers on the Structure, Physical Properties and Film Forming Performance of Curdlan Edible Films.

This study successfully developed edible films with excellent mechanical strength and notable water resistance, utilizing curdlan (CL) as the primary matrix and incorporating various plasticizers, including glycerol (GLY), ethylene glycol (EG), propylene glycol (PRO), xylitol (XY), sorbitol (SOR), and polyethylene glycol (PEG). A comprehensive suite of analytical techniques, including Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), and tensile testing, were employed to evaluate the films' structural and mechanical properties. After incorporating PEG, the water sensitivity increased slightly, with a contact angle (CA) of 97.6°, and a water solubility (WS) of 18.75%. The inclusion of plasticizers altered the crystalline structure of the CL matrix, smoothing and flattening the film surface while reducing hydrogen-bonding interactions. These structural changes led to a more uniform distribution of amorphous chain segments and a decrease in glass transition temperatures. Among the tested plasticizers, GLY exhibited the highest compatibility with CL, resulting in the smoothest surface morphology and delivering the most effective plasticizing effect. The CL-GLY film showed a dramatic improvement in flexibility, with an elongation at break that was 5.2 times higher than that of the unplasticized film (increasing from 5.39% to 33.14%), indicating significant enhancement in extensibility. Overall, these findings highlight the potential of CL-GLY films as sustainable and effective materials for food packaging applications.

Synthesis and Electron-Transporting Properties of N-Type Polymers with Cardanol-Based Side Chains.

We synthesized n-type polymers poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} [P(NDI2OD-T2)] and poly{[N,N'-bis(3-(4-cardanol)propyl)-naphthalene-1,4,5,8-tetracarboxylic diimide]-alt-[5,5'-bis(2-thienyl)-2,2'-bithiophene]} [P(NDICL-T2)] with cardanol-based side chains via Stille coupling to enhance electron mobility. Replacing the 2-octyldodecyl side chain with cardanol in P(NDICL-T2) improved electron mobility due to increased chain flexibility and ordered packing. Lower glass transition temperature (tg), red-shifted UV-vis absorption, results from crystalline structure analysis, indicating tighter lamellar spacing and enhanced molecular ordering, and smoother surface morphology confirmed the enhanced intermolecular interactions and uniform film formation.

Effect of Alkyl Side Chain Length on Electrical Performance of Ion-Gel-Gated OFETs Based on Difluorobenzothiadiazole-Based D-A Copolymers.

The performance of organic field-effect transistors (OFETs) is highly dependent on the dielectric-semiconductor interface, especially in ion-gel-gated OFETs, where a significantly high carrier density is induced at the interface at a low gate voltage. This study investigates how altering the alkyl side chain length of donor-acceptor (D-A) copolymers impacts the electrical performance of ion-gel-gated OFETs. Two difluorobenzothiadiazole-based D-A copolymers, PffBT4T-2OD and PffBT4T-2DT, are compared, where the latter features longer alkyl side chains. Although PffBT4T-2DT shows a 2.4-fold enhancement of charge mobility in the SiO2-gated OFETs compared to its counterpart due to higher crystallinity in the film, PffBT4T-2OD outperforms PffBT4T-2DT in the ion-gel-gated OFETs, manifested by an extraordinarily high mobility of 17.7 cm2/V s. The smoother surface morphology, as well as stronger interfacial interaction between the ion-gel dielectric and PffBT4T-2OD, enhances interfacial charge accumulation, which leads to higher mobility. Furthermore, PffBT4T-2OD is blended with a polymeric elastomer SEBS to achieve ion-gel-gated flexible OFETs. The blend devices exhibit high mobility of 8.6 cm2/V s and high stretchability, retaining 45% of initial mobility under 100% tensile strain. This study demonstrates the importance of optimizing the chain structure of polymer semiconductors and the semiconductor-dielectric interface to develop low-voltage and high-performance flexible OFETs for wearable electronics applications.

Sustainable Fabrication of Ge Freestanding Membranes and Substrate Reuse via Porosification Lift-Off

Recent advancements in flexible optoelectronics have spurred interest in developing nanoengineered substrates essential for the growth and fabrication of freestanding membranes (FSMs). The FSMs offer an extra degree of flexibility in applications previously unachievable through conventional techniques, such as the heterointegration of highly dissimilar materials. These membranes allow the stacking of various dissimilar materials, enabling the seamless coupling of their physical properties and integration onto a variety of substrates. Additionally, the use of FSMs instead of bulk materials significantly reduces costs and material usage during device production—a crucial advantage for non-silicon materials, which are considerably more expensive than silicon. Techniques such as substrate thinning, 2D-assisted epitaxy, and various substrate engineering approaches have demonstrated great potential for fabricating lightweight and flexible devices, underscoring the promise of FSM technology. However, the efficient production of FSMs based on germanium (Ge) and its alloys is still a challenging task.In this work, we present the porosification lift-off process, which involves the sequential formation of porous Ge (PGe) nanostructure formation, epitaxial growth of Ge membrane, detachment, substrate reconditioning, and subsequent reuse. We demonstrate edge-to-edge formation of PGe nanostructures across 100 mm Ge wafers with excellent uniformity (Fig. 1a) using bipolar electrochemical etching[1]. Moreover, the physical properties (Thickness and porosity) of these structures can be efficiently tailored to suit specific applications by adjusting the etching parameters. These PGe structures maintain their substrate-oriented crystalline nature and exhibit smooth surface morphology, making them ideal substrates for epitaxial growth. Thin Ge FSMs are grown atop these PGe structure (Fig. 1b) at low temperature, preventing the PGe transformation into large pillars[2]. The initial growth stages on nanostructured substrate are investigated, showing the membrane formation process starting with initial 3D nucleation atop of the pore walls, followed by the coalescence of nucleation seeds into dense membrane, and concluding with the surface flattening by final 2D growth mode. This process allows for the growth of even ultrathin membranes with thickness as low as 60 nm. The high-quality monocrystalline nature of these membranes is confirmed by a thorough XRD analysis. After membrane formation, the underlying PGe structure provides a weak interface that allows easy detachment and transfer of the Ge FSM (Fig. 1c). Furthermore, the remnants of the unreconstructed PGe structure on the parent substrate can be dissolved using slow chemical etching in H2O2 solution, enabling the recovery of an epiready surface and its reporosification to produce multiple Ge FSMs. These findings provide a groundwork for engineering of Ge substrates and their application in the sustainable fabrication of high-quality Ge FSMs for lightweight and flexible optoelectronic devices.[1] T. Hanuš et al., Adv. Mater. Interfaces (2023), 2202495 (https://doi.org/10.1002/admi.202202495)[2] T. Hanuš et al., Mater. Today Adv. 18 (2023), 100373 (https://doi.org/10.1016/j.mtadv.2023.100373)[3] T. Hanuš et al., Sustainability (2024), 16(4), 1444 (https://doi.org/10.3390/su16041444) Figure 1

Effect of substrate misorientation angle on the structural properties of N-polar GaN grown by hot-wall MOCVD on 4H-SiC(000[formula omitted])

The effects of substrate misorientation angle direction and degree on the structural properties of N-polar GaN grown by a novel multi-step temperature epitaxial approach using hot-wall metal–organic chemical vapor deposition (MOCVD) on 4H-SiC (0001̄) substrates is investigated. The surface morphology and X-ray diffraction (XRD) rocking curves (RCs) for both symmetric and asymmetric Bragg peaks of the multi-step temperature N-polar GaN are compared to a material obtained in a two-step temperature process. In the latter the temperature in the second step was varied so that it corresponds to the growth temperatures in each of the steps of the multi-step process. Different step-flow patterns are obtained on the substrates with a misorientation angle of 4° depending on whether its direction is towards the a-plane or the m-plane. In contrast, for a misorientation angle of 1° towards the m-plane, the surface morphology of N-polar GaN is dominated by hexagonal hillocks when using the 2-step temperature process and a step meandering growth mode is observed when employing the multi-step temperature process. These results are discussed and explained in terms of kinetic and thermodynamic considerations. As the growth temperature of the GaN layer in the 2-step temperature process increases from 950 °C to 1100 °C, the surface roughness and RCs widths decrease for the three types of substrates indicating improved crystal quality at higher temperature. The multi-step epitaxial approach is shown to be beneficial for achieving smooth surface morphology and low defect density of N-polar GaN layers grown on C-face SiC substrates with a misorientation angle of 4° and an RMS value of 1.5 nm over an area of 20 μm × 20 μm is attained when the substrate mis-cut is towards the m-plane.

Large-Area Metal-Organic Framework Glasses for Efficient X-Ray Detection.

Cutting-edge techniques utilizing continuous films made from pure, novel semiconductive materials offer promising pathways to achieve high performance and cost-effectiveness for X-ray detection. Semiconductive metal-organic framework (MOF) glass films are known for their remarkably smooth surface morphology, straightforward synthesis, and capability for large-area fabrication, presenting a new direction for high-performance X-ray detectors. Here, a novel material centered on MOF glasses for highly uniform glass film fabrication customized for X-ray detection is introduced. MOF glasses, composed of zinc and imidazole derivatives, enable the transition from solid to liquid at low temperatures, facilitating the straightforward preparation of large-area and continuous MOF films with high mobility for X-ray device fabrication. Remarkably, MOF glass detectors demonstrate an exceptional sensitivity of 112.8 µC Gyair -1 cm-2 and a detection limit of 0.41 µGyair s-1, making them one of the most sensitive and with the best detection limits reported to date for MOF X-ray detectors. Clear X-ray images are successfully conducted using these developed MOF glass detectors for the first time. This breakthrough in X-ray sensitivity, and detection limit along with the spatial imaging resolution establishes a new standard for developing large-area and efficient MOF-based X-ray detectors with practical applications in medical and security screening.

UV-curable polymer-treated polydimethylsiloxane substrate for ultrahigh-efficient flexible organic light-emitting diodes

Flexible organic light-emitting diodes (FOLEDs) have developed rapidly and have been successfully implemented in the technology of foldable smartphones. As one of the most promising flexible substrates, polydimethylsiloxane (PDMS) suffers from the drawbacks of low thermal stability and weak interfacial adhesion with the low-cost solution-processed poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) film electrodes. In this work, a UV-curable polymer, Norland Optical Adhesive 63 (NOA63), is proposed to enhance the thermal stability and interfacial adhesion, as well as facilitating the light extraction of PDMS substrate. The PEDOT:PSS electrode film on the NOA63 modified PDMS substrate performs a uniform and smooth surface morphology with a low roughness of 3.1 nm, a high transmittance of 94.7 % at 550 nm wavelength, a low sheet resistance of 160 Ω/sq, and superior mechanical durability even after 18,000 bending cycles. The outstanding characteristics of the PDMS/NOA63 substrate enables the fabrication of an ultrahigh-efficient FOLED with a maximum current efficiency, power efficiency and external quantum efficiency of 230.6 cd/A, 144.9 lm/W and 65 %, respectively. This study paves the way to realize high-performance FOLEDs for wearable electronics in the future.

A universal reverse‐cool annealing strategy makes two‐dimensional Ruddlesden‐popper perovskite solar cells stable and highly efficient with Voc exceeding 1.2 V

AbstractTwo‐dimensional Ruddlesden‐Popper (2D RP) layered metal‐halide perovskites have garnered increasing attention due to their favorable optoelectronic properties and enhanced stability in comparison to their three‐dimensional counterparts. Nevertheless, precise control over the crystal orientation of 2D RP perovskite films remains challenging, primarily due to the intricacies associated with the solvent evaporation process. In this study, we introduce a novel approach known as reverse‐cool annealing (RCA) for the fabrication of 2D RP perovskite films. This method involves a sequential annealing process at high and low temperatures for wet perovskite films. The resulting RCA‐based perovskite films show the smallest root‐mean‐square value of 23.1 nm, indicating a minimal surface roughness and a notably compact and smooth surface morphology. The low defect density in these 2D RP perovskite films with exceptional crystallinity suppresses non‐radiative recombination, leading to a minimal non‐radiative open‐circuit voltage loss of 149 mV. Moreover, the average charge lifetime in these films is extended to 56.3 ns, thanks to their preferential growth along the out‐of‐plane direction. Consequently, the leading 2D RP perovskite solar cell achieves an impressive power conversion efficiency of 17.8% and an open‐circuit voltage of 1.21 V. Additionally, the stability of the 2D RP perovskite solar cell, even without encapsulation, exhibits substantial improvement, retaining 97.4% of its initial efficiency after 1000 hours under a nitrogen environment. The RCA strategy presents a promising avenue for advancing the commercial prospects of 2D RP perovskite solar cells.image

PLA/PLGA nanocarriers fabricated by microfluidics-assisted nanoprecipitation and loaded with Rhodamine or gold can be efficiently used to track their cellular uptake and distribution

This study represents a pioneering investigation into using microfluidic technology for manufacturing PLA and PLGA nanocarriers (NCs) loaded with tracer molecules or metals through a co-precipitation protocol that involves saturating the water phase. The effects of total flow rate (TFR), flow rate ratio (FRR), surfactant amount, and polymer concentration on particle sizes and distributions were examined. The average size of PLA-NCs varied from 349 ± 175 nm to 170 ± 64 nm, with surface charges ranging from −13 to −6 mV. In contrast, PLGA-NCs had an average size between 192 ± 46 nm and 100 ± 34 nm, with surface charges from –23 mV to −53 mV. Increasing the TFR from 6 to 10 mL/min with a fixed FRR of 1:1 and reducing polymer concentrations in the organic phase from 20 to 5 mg/mL generally resulted in smaller NC sizes and distributions (monodispersed), with PLGA-NCs consistently exhibiting smaller dimensions. Under these specific conditions, Rhodamine B (Rhod) and gold (Au) were successfully loaded, achieving encapsulation efficiencies exceeding 50 %. Electron microscopy analysis confirmed that the nanocarriers exhibited a consistent spherical shape with smooth surface morphology. X-ray energy-dispersive spectroscopy (EDX) revealed a uniform distribution of gold within the polymer matrix. PLA-NCs were effectively internalized by various cell types, including human Peripheral Blood Mononuclear Cells (PBMCs), HT-29 colon cancer cells, and C6 glioma cells. Uptake occurred in a dose-dependent manner for PLA-NCs sized at 260 ± 51 nm, with only 30 % internalization at 2 mg/mL concentration after 24 to 48 h. Notably, smaller PLA-NCs with a mean size of 170 ± 64 nm achieved nearly 100 % uptake across all tested cell types after 48 h, indicating that particle size significantly influenced cellular uptake.

Pyridalthiadiazole-Based Molecular Chromophores for Defect Passivation Enables High-Performance Perovskite Solar Cells.

Passivation of defects at the surface and grain boundaries of perovskite films has become one of the most important strategies to suppress nonradiative recombination and improve optoelectronic performance of perovskite solar cells (PSCs). In this work, two conjugated molecules, abbreviated as CPT and SiPT, are designed and synthesized as the passivator to enhance both efficiency and stability of PSCs. The CPT and SiPT contain pyridalthiadiazole (PT) units, which can coordinate with undercoordinated Pb2+ at the surface and grain boundaries to passivate the defects in perovskite films. In addition, with the incorporation of CPT, the crystallized perovskite films exhibit more uniform grain size and smoother surface morphology relative to the control ones. The efficient passivation by CPT also results in better charge extraction and less carrier recombination in PSCs. Consequently, the CPT-passivated PSCs yield the highest power conversion efficiency (PCE) of 23.14 % together with better storage stability under ambient conditions, which is enhanced relative to the control devices with a PCE of 22.14 %. Meanwhile, the SiPT-passivated PSCs also show a slightly enhanced performance with a PCE of 22.43 %. Our findings provide a new idea for the future design of functional passivating molecules towards high-performance PSCs.