Passivating Agent Research Articles

Carbon nanoprobe derived from Nyctanthes arbor-tristis flower: Unveiling the surface defect-derived fluorescence

Dual Emissive (green and blue) Carbon dots (C-Dots) aka g-CD and b-CD were synthesized using flowers of Nyctanthes arbortristis as the sole precursor via hydrothermal method without the aid of any external passivating agent. In the present report, the effect of time and temperature on the hydrothermal reaction was evaluated in order to modulate the surface defects that could lead to dual emissions. To gauge the nature, size, morphology, and optoelectronic characteristics, the C-Dots were characterized using high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), UV–Vis spectroscopy and Fluorescence spectroscopy. The fluorescence studies of both the Carbon Dots revealed their excitation-dependent emission characteristics with the bathochromic shift. Furthermore, both g-CD and b-CD could effectively be utilized as efficient fluorescent probes for the selective and sensitive detection of Fe3+. These fluorescent nanoprobes could selectively detect Fe3+ over a wide range of concentrations (3 µM to 100 µM) with limit of detection (LOD) as low as 0.06 µM and 0.70 µM respectively. These tuneable Carbon Dots having wider solubilities would open a new avenue as Nanosensors for real-time applications.

Remediation Effect of Two Iron-modified Biochars on Slightly Alkaline Arsenic and Cadmium Contaminated Soil

As a good passivation agent for heavy metals, modified biochar has been widely used in environmental remediation. In order to explore the effects of different modification methods on arsenic (As) and cadmium (Cd) passivation in soil by biochar, this study used co-precipitation and impregnation pyrolysis to prepare iron-modified biochar. Through adsorption experiments and soil culture experiments, the properties of biochar, adsorption capacity, and the As and Cd passivation ability in soil were analyzed. The results showed that both modification methods could increase the iron (Fe) content and zero charge point of biochar, and the Fe minerals supported by Fe-modified biochar (FeBC-1) prepared by co-precipitation were mainly Fe3O4, FeO(OH), and γ-Fe2O3. The Fe-modified biochar (FeBC-2) prepared by impregnation pyrolysis mainly consisted of α-Fe2O3 and γ-Fe2O3. FeBC-1 showed strong adsorption and removal ability for As and Cd, with a removal rate of 21.40%-34.14%, which could significantly promote the conversion of non-obligate adsorbed As to residual As in soil, whereas FeBC-2 only had a good adsorption effect on As. The adsorption capacity of BC, FeBC-1, and FeBC-2 for Cd were proportional to their CEC. The adsorption and removal effect of BC on Cd was better than that of FeBC-1 and FeBC-2, which could significantly promote the conversion of soil acid-soluble Cd to stable residue Cd.

Surface defect passivation of All-Inorganic CsPbI2Br perovskites via fluorinated ionic liquid for efficient Outdoor/Indoor photovoltaics processed in ambient air

All-inorganic α-CsPbI2Br perovskite has garnered considerable interest due to its optical bandgap (∼1.92 eV) suitable for tandem architectures and superior thermal stability. However, CsPbI2Br based perovskite solar cells (PSCs) exhibit severe energy loss due to presence of various surface defects like uncoordinated Pb2+ ions, halide ion vacancies and pinholes, which causes serious non-radiative recombination and limit the further improvement in power conversion efficiency (PCE). Surface passivation strategy is an effective approach to produce high quality α-CsPbI2Br film. Herein, we introduce fluorinated ionic liquid, 3-(Trifluoromethyl) benzylamine (CFBA), as surface passivating agent. The chemical analysis shows that the trifluoro (-CF3) and amine groups of CFBA strongly interacted with perovskite surface via forming Pb-F and H-I bonding, respectively. The high electronegative fluoride atoms of -CF3 group allow for electrostatic interaction with uncoordinated Pb2+ ions, which built a robust shield that protected against surrounding moisture as well. In addition, CFBA modification passivates the dangling bonds, enhanced crystallinity, reduced pinholes, improved the surface coverage and compactness, increased hydrophobicity, and decreased non-radiative recombination, leading to high PCE. With optimum concentration of 3 μL-CFBA, CsPbI2Br PSC revealed an impressive PCE of 17.07% with FF of 83.21% as compared to pristine device (PCE of 15.24% with FF of 79.81%). Moreover, champion device showed an excellent thermal stability by retaining ∼ 86.23% of its initial PCE, whereas pristine device maintained ∼ 48.26% of its original PCE after 1440 h aging at 85 ℃ in a dry box without any encapsulation. In addition, optimized PSC showed a decent indoor PCE of 23.24% as compared to pristine device (18.35%) under dim lighting conditions (LED, 3200 K) at 1000 lx. These results suggested that surface passivation strategy with CFBA is a promising approach for developing efficient all-inorganic CsPbI2Br outdoor/indoor PSCs with better thermal stability.

Enhancing the Performance of Perovskite Solar Cells by Introducing 4-(Trifluoromethyl)-1H-imidazole Passivation Agents.

Defects in perovskite films are one of the main factors that affect the efficiency and stability of halide perovskite solar cells (PSCs). Uncoordinated ions (such as Pb2+, I-) act as trap states, causing the undesirable non-radiative recombination of photogenerated carriers. The formation of Lewis acid-base adducts in perovskite directly involves the crystallization process, which can effectively passivate defects. In this work, 4-(trifluoromethyl)-1H-imidazole (THI) was introduced into the perovskite precursor solution as a passivation agent. THI is a typical amphoteric compound that exhibits a strong Lewis base property due to its lone pair electrons. It coordinates with Lewis acid Pb2+, leading to the reduction in defect density and increase in crystallinity of perovskite films. Finally, the power conversion efficiency (PCE) of PSC increased from 16.49% to 18.97% due to the simultaneous enhancement of open-circuit voltage (VOC), short circuit current density (JSC) and fill factor (FF). After 30 days of storage, the PCE of the 0.16 THI PSC was maintained at 61.9% of its initial value, which was 44.3% for the control device. The working mechanism of THI was investigated. This work provides an attractive alternative method to passivate the defects in perovskite.

A functionalized phosphorous tetrabenzotriazacorrole dye as a novel passivating agent of high-performance planar perovskite solar cells

Surface passivation is a crucial strategy to manage the film characteristics of solution-processed perovskite absorber layers, which greatly impact the photovoltaic properties of perovskite solar cells (PSCs). However, designing and synthesizing suitable passivating agents with required functional groups and solution-processability is challenging due to their complex molecular structure. In this study, we demonstrate a facile passivation technique using a functionalized phosphorous tetrabenzotriazacorrole dye (PTBC) for p-i-n PSCs. The tetrabenzotriazacorrole dye has amines and ether linkages that can closely interact with the undercoordinated Pb2+ with halogen vacancies through Lewis acid-base interactions, leading to a pinhole-free perovskite absorber layer with reduced trap density. Moreover, the central phosphorus of PTBC is functionalized with dimethoxy groups, which can provide a more hydrophobic surface in the perovskite absorber layer. Consequently, high-quality perovskite films (CsFAPbI3) prepared with PTBC exhibit improved optical, electrical, and morphological properties, as well as superior carrier transportation/recombination kinetics, boosting the power conversion efficiency of PSCs from 17.64 % to 20.08 %, with over 75 % of initial efficiency preserved after 1000 h of aging under ambient conditions. These results highlight PTBC as an effective surface passivation agent for perovskite absorber layers and emphasize the importance of suitable passivating agents in optimizing PSC performance.

Surface Passivation with Selected Phosphine Oxide Molecules for Efficient Pure‐Blue Mixed‐Halide Perovskite Quantum Dot Light‐Emitting Diodes

AbstractPassivation of defects in halide perovskite using phosphine oxide or alkyl‐phosphonate has recently obtained a few remarkable achievements. However, effective application of phosphine oxide or alky‐phosphonate in passivating perovskite quantum dots (QDs) are seldom reported due to solubility issue or difficulty of amount control. In this work, two bifunctional organic molecules containing phosphine oxide groups, 2,4,6‐Tris[3‐(diphenylphosphinyl)phenyl]‐1,3,5‐triazine (PO‐T2T) and 2,7‐bis(diphenylphosphoryl)‐9,9′‐spirobifluorene (SPPO13), are deposited on QDs films by thermal evaporation. The molecules, both as passivation agents as well as electron transporting materials, exhibit stark contrast in passivating QDs and in light‐emitting diodes (LEDs) performance. A competition between charge transfer and defect passivation between the QDs and the molecules is proposed. In film, electron transfer from the QDs to PO‐T2T dominates and quench the QDs, while the passivation effect of PO‐T2T on the QDs dominates in driving device and enhances luminance of the LEDs. In contrast, passivation effect of SPPO13 on the QDs dominates both in films and in LEDs. A maximum EQE of 2.67% is obtained for the pure‐blue LED based on SPPO13‐passivated QDs films. This work provides a guide on the selection of passivation agents based on phosphine oxide and a promising passivation method for high‐efficient perovskite QD LEDs.

Enhanced Open-Circuit Voltage and Improved Stability with 3-Guanidinoproponic Acid as the Passivation Agent in Blade-Coated Inverted Perovskite Solar Cells

The formation of high-density charge trap states along the surface and grain boundaries of the perovskite absorber is a major cause of recombination that limits the efficiency and quickly degrades the long-term stability of perovskite solar cells (PSCs). To improve the PSC performance, we investigated the use of amino acids with Lewis acid–base functional groups, namely, 2-guanidinoacetic acid, l-aspartic acid, l-glutamic acid, and 3-guanidinoproponaic acid (3gpa), as passivating dopants for blade-coated perovskite films. The best photovoltaic performance was achieved with 4 mol% 3gpa doping, which effectively passivated both positively and negatively charged defects, resulting in a 12.9% improvement in the open-circuit voltage and a high PCE of 19.83%. Additionally, the improved carrier lifetime and reduced defect density led to improved long-term stability in blade-coated PSCs.

A Novel Multi‐Functional Thiophene‐Based Organic Cation as Passivation, Crystalline Orientation, and Organic Spacer Agent for Low‐Dimensional 3D/1D Perovskite Solar Cells

AbstractRecently, the mixed‐dimensional (3D/2D or 3D/1D) perovskite solar cells using small organic spacers have attracted interest due to their outstanding long‐term stability. Here, a new type of thiophene‐based organic cation 2‐(thiophene‐2yl‐)pyridine‐1‐ium iodide (ThPyI), which is used to fabricate mixed‐dimensional 3D/1D perovskite solar cells, is presented. The ThPyI‐based 1D perovskitoid is applied as a passivator on top of a 3D methyl ammonium lead iodide (MAPI) to fabricate surface‐passivated 3D/1D perovskite films or added alone into the 3D perovskite precursor to generate bulk‐passivated 3D MAPI. The 1D perovskitoid acts as a passivating agent at the grain boundaries of surface‐passivated 3D/1D, which improves the power conversion efficiency (PCE) of the solar cells. Grazing incidence wide‐angle X‐ray scattering (GIWAXS) studies confirm that ThPyI triggers the preferential orientation of the bulk MAPI slabs, which is essential to enhance charge transport. Champion bulk‐passivated 3D and surface‐passivated 3D/1D devices yield 14.10% and 19.60% PCE, respectively. The bulk‐passivated 3D offers favorable stability, with 84% PCE retained after 2000 h without encapsulation. This study brings a new perspective to the design of organic spacers having a different binding motif and a passivation strategy to mitigate the impact of defects in hybrid 3D/1D perovskite solar cells.

Silver nanoparticles passivated with aniline and their subsequent polymerization using hematin as a catalyst

In this work, silver nanoparticles (AgNPs) were synthesized via two different routes. The first route was based on the Creighton method (chemical reduction), used aniline as a passivating agent and NaBH4 as a reducing agent, and led to a green nanoparticle solution with an average particle size of 23 ​± ​11 ​nm and a plasmonic resonance with a maximum at 376 ​nm. The second route was the hydrothermal method, in which aniline was used to reduce the metal salt and stabilize the nanoparticles; this provided a pink solution of nanoparticles with an average particle size of 11 ​± ​5 ​nm, and a plasmon resonance with a maximum at 550 ​nm. Aniline was polymerized by using hematin as the catalyst, and FT-IR, RAMAN, and NMR spectroscopy were used to characterize the structure. In addition, the PANI/AgNP composite was synthesized, and it exhibited a higher conductivity of 0.28 ​S/cm relative to that of PANI (0.05 ​S/cm).

Visible Light-Mediated Quantum Dot Photocatalysis Enables Olefination Reactions at Room Temperature

The ability of quantum dots (QDs) to photocatalyze organic reactions is gaining attention because of their distinct light harvesting properties over traditional precious metal- and small molecule-based catalysts. However, establishing the potency of QD photocatalysts in diverse and useful organic transformations, as well as deciphering the charge transfer mechanism, is essential to cement their place as an efficient photocatalyst in synthetic chemistry. Here, we report the use of QDs in efficiently catalyzing a series of olefination reactions under visible-light irradiation at room temperature (90% yield). Spectroscopic and electrochemical studies reveal intriguing insights on the charge transfer mechanism involved in QD-photocatalyzed olefination. Interestingly, the dual role of triphenylphosphine─as a surface passivating agent and nucleophile─turned out to be decisive in directing the charge transfer process from the QD to the reactant. Benzyl triphenylphosphonium bromide salt was accepting the electrons from the photoexcited QDs, thereby initiating the catalytic olefination reaction. QD-photocatalyzed olefination was demonstrated with formaldehyde as well, resulting in the formation of industrially relevant terminal alkene, namely styrene. Moreover, the environmentally friendly indium phosphide (InP) QD also photocatalyzed the olefination reaction under mild reaction conditions, which proves the practical suitability of our study. This work presents an attractive and efficient way to introduce double bonds in organic molecules using QDs and visible light at room temperature.

The Effect of Different Stabilisers on Stability and Photothermal Profiling of Gold Nanorods

AbstractThe photothermal application of gold nanorods (AuNRs) as a photothermal agent has gained popularity due to their optical, photothermal and biological properties. However, AuNRs are synthesised using a biotoxic surfactant (cetyl trimethyl ammonium bromide) which limits their biological applications. Though different techniques have been established to address this challenge using different stabilizers or passivating agents, the effect of these stabilizers on AuNRs' colloidal stability, thermal stability, and photothermal conversion efficiency still need to be investigated. In this study, we evaluated the effect of different polymers or stabilisers; two synthetic polymers [methoxy polyethylene glycol thiol (mPEG-SH) and polyvinylpyrrolidone (PVP)] and one biopolymer (gelatin) on the stability and photothermal properties of AuNRs. AuNRs absorbing around 800 nm were synthesised and coated with these three stabilisers. The colloidal stability of the as-synthesised material was evaluated in Dulbecco's phosphate-buffered saline (PBS) and Roswell Park Memorial Institute (RPMI-1640) using Ultraviolet–Visible–Near-Infrared (UV–Vis–NIR). The results show that PEG@AuNRs was more stable in both media due to fewer functional groups on its structure to bond with ions and protein. PVP@AuNRs showed good thermal stability under heat incubation (at 37, 50 and 70 °C) for 24 h because of its high thermal decomposition properties, while PEG@AuNRs proved superior in improving the AuNRs heat generation. In addition, coating with different polymers did not affect the photothermal ability of AuNRs. This study demonstrated that it is crucial to choose polymers with less functional groups when coating nanoparticles for biological application.

Mulberry Leaves (Morus rubra)-Derived Blue-Emissive Carbon Dots Fed to Silkworms to Produce Augmented Silk Applicable for the Ratiometric Detection of Dopamine.

Silk fibers (SF) reeled from silkworms are constituted by natural proteins, and their characteristic structural features render them applicable as materials for textiles and packaging. Modification of SF with functional materials can facilitate their applications in additional areas. In this work, we report the preparation of functional SF embedded with carbon dots (CD) through the direct feeding of a CD-modified diet to silkworms. We obtained fluorescent and mechanically robust SF from silkworms (Bombyx mori) that were fed on CDs synthesized from the Morus rubra variant of mulberry leaves (MB-CDs). MB-CDs were introduced to silkworms from the third instar onwards by spraying them on the silkworm feed, the mulberry leaves. MB-CDs were synthesized hydrothermally without adding surface passivating agents and were observed to have a quantum yield of 22%. With sizes of ∼4nm, MB-CDs exhibited blue fluorescence, and they can be used as efficient fluorophores to detect Dopamine (DA) up to the limit of 4.39nM. The nanostructures and physical characteristics of SF weren't altered when the SF were infused with MB-CDs. Also, we demonstrate a novel DA sensing application based on fluorescence with the MB-CD incorporated SF. The MB-CD-embedded SF thus open up intriguing prospects for fluorescent micro-devices and fabrics. This article is protected by copyright. All rights reserved.

Surface Passivation of FAPbI3-Rich Perovskite with Cesium Iodide Outperforms Bulk Incorporation

Metal halide perovskites (MHPs) have shown an incredible increase in efficiency, reaching as high as 25.7%, which now competes with traditional photovoltaic technologies. Herein, we excluded CsX and RbX (X = I–, Br–, Cl–), the most commonly used cations to stabilize α-FAPbI3, from the bulk of perovskite thin films and applied them on the surface as passivation agents. Extensive device optimization led to a power conversion efficiency (PCE) of 24.1% with a high fill factor (FF) of 82.2% upon passivation with CsI. We investigated in depth the effect of CsI passivation on structural and optoelectronic properties using X-ray diffraction (XRD), angle-resolved X-ray photoelectron spectroscopy (ARXPS), Kelvin probe force microscopy (KPFM), time-resolved photoluminescence (TRPL), photoluminescence quantum yield (PLQY), and electroabsorption spectroscopy (TREAS). Furthermore, passivated devices exhibit enhanced operational stability, with optimized passivation with CsI leading to a retention of ∼90% of the initial PCE under 1 sun illumination with maximum power point tracking for 600 h.

Study on formation mechanism and corrosion resistance of an environmentally protective insulating coating on non-oriented electrical steel

In the present work, we developed an environmentally protective insulating coating for non-oriented electrical steel, which was composed of phosphate film-forming agent, rare-earth passivating agent, silane coupling agent and polyurethane additive. The morphology, composition, electrochemical properties and corrosion resistance of the coating were characterized by scanning electron microscopy (SEM), confocal Raman microscopy (CRM), scanning vibrating electrode technique (SVET), and electrochemical measurements. The formation mechanism of the coating revealed that the synergistic effect of rare-earth passivating agent and silane coupling agent made the distribution of rare-earth oxides uniform and hindered the agglomeration of phosphate. Further addition of polyurethane formed cross-linked network structures with the original coating to enhance corrosion resistance. The electrochemical results indicated a relatively low corrosion current density (0.12 μA cm−2) and a relatively high polarization resistance (143 kΩ cm2). The SVET results illustrated a good passivation effect of the coating, contributing to a continuous protection to the substrate. In addition, the coating could withstand the annealing test for 2 h and resist the neutral salt spray test for 8 h. Consequently, the comprehensive properties of the coating were found to be higher than industrial standards, satisfying application requirements for non-oriented electrical steel.

A facile surface trap passivation of perovskite absorber enabled by tetrabenzocorrolazine dye for efficient and stable planar perovskite solar cells

The trap-site passivation of perovskite absorbers is very important for reducing charge recombination and resultant energy loss in high-performance perovskite solar cells (PSCs). To achieve the successful role of a passivating agent, an appropriate molecular design strategy with specific functional groups should be considered for effective passivation of the defective antisites on the surface of perovskite absorber layers. Here, we designed a tetrabenzocorrolazine phosphorus dye (RC1), that is capable of electron-donating properties with a hydroxyl functionalization, as a multi-functional passivation agent for high-performance PSCs. It is found that the surface properties of the perovskite absorber were stabilized as RC1 interacts with Pb2+ and Cs + cations of the perovskite lattice, providing much improved optoelectronic properties and their charge extraction/collection capability. Moreover, the RC1-passivation successfully reduced carrier recombination and internal energy loss, leading to hysteresis-free power conversion efficiency of 18.922% (14.466% for the control device). The RC1 also retains long-term stability for 2000 h with only 10% efficiency loss of the fresh device. Thus, this study demonstrates a successful passivating capability of functionalized tetrabenzocorrolazine phosphorus dye for high-performance PSCs.

Improving the Solar Energy Utilization of Perovskite Solar Cells via Synergistic Effects of Alkylamine and Alkyl Acid on Defect Passivation

Defects in perovskite film are sources of charge recombination centers, which are detrimental to the performance of perovskite solar cells (PSCs). To decrease the density of defects, dodecylamine (DAM), dodecylic acid (DAC), and 12‐aminolauric acid (ALA) are utilized as additives to prepare methyl ammonium lead iodide (MAPbI3) perovskite films. Herein, the passivation effects of these molecules on the properties of the MAPbI3 films and the performances of the corresponding PSCs are studied. The results show that DAM and DAC which contain –NH2 and –COOH groups, respectively, can increase the PCEs of the devices. This result implies that both groups serve as the Lewis base, passivating the defects of undercoordinated Pb2+. For the ALA molecules, the –NH2 and –COOH groups are present simultaneously at the two ends of the molecule; the passivation ability is more significant than the others, which is attributable to the synergistic effects of the two groups. By the passivation of ALA, the PCE of the PSC can increase from 18.42% to 19.96% under one sun illumination. Furthermore, the treatments of the passivation agents also increase the hydrophobicity of the perovskite films, improving the stability of the PSCs.

Methoxy Functionalization of Phenethylammonium Ligand for Efficient Perovskite Light‐Emitting Diodes

AbstractAlthough the electroluminescent performances of perovskite light‐emitting diodes (PeLEDs) are continuously improved through defect management strategies, the complicated design of passivation ligands brings great challenges to the rational defect‐annihilation process. Herein, considering the bonding strength with uncoordinated Pb2+, the methoxy group with strong electron donating ability is introduced to commonly used phenethylammonium ligand as an efficient additive, namely 4‐methoxy‐phenethylammonium iodide (4‐MeO‐PEAI), to facilitate passivation process in perovskite light‐emitting materials. It is demonstrated that the 4‐MeO‐PEAI agent substantially increases the crystal orientation, enlarges the crystalline grain size, and mitigates the deep‐level trap centers through strong bonding between the methoxy group with unpaired Pb2+ ions. The external quantum efficiencyvalue of the PeLEDs with optimized passivation reaches a maximum of 21.6%, with an emission peak of 790 nm. In addition, a nearly threefold increase of the operational half‐lifetime T50 of the 4‐MeO‐PEAI‐mediated devices is observed as compared to the reference sample. Further theoretical calculation results suggest that the adhesion of the ligands on perovskite surface via vacancies leads to an increased dissociation barrier of perovskite; thus, ameliorating the degradation of the PeLEDs under electric field. The findings provide an effective design strategy of the passivation agents to produce high‐performance perovskite‐based optoelectronics devices.

Surface Passivation by Sulfur-Based 2D (TEA)2PbI4 for Stable and Efficient Perovskite Solar Cells.

Perovskite solar cells (PSCs) with superior performance have been recognized as a potential candidate in photovoltaic technologies. However, defects in the active perovskite layer induce nonradiative recombination which restricts the performance and stability of PSCs. The construction of a thiophene-based 2D structure is one of the significant approaches for surface passivation of hybrid PSCs that may combine the benefits of the stability of 2D perovskite with the high performance of three-dimensional (3D) perovskite. Here, a sulfur-rich spacer cation 2-thiopheneethylamine iodide (TEAI) is synthesized as a passivation agent for the construction of a three-dimensional/two-dimensional (3D/2D) perovskite bilayer structure. TEAI-treated PSCs possess a much higher efficiency (20.06%) compared to the 3D perovskite (MA0.9FA0.1PbI3) devices (17.42%). Time-resolved photoluminescence and femtosecond transient absorption spectroscopy are employed to investigate the effect of surface passivation on the charge carrier dynamics of the 3D perovskite. Additionally, the stability test of TEAI-treated perovskite devices reveals significant improvement in humid (RH ∼ 46%) and thermal stability as the sulfur-based 2D (TEA)2PbI4 material self-assembles on the 3D surface, making the perovskite surface hydrophobic. Our findings provide a reliable approach to improve device stability and performance successively, paving the way for industrialization of PSCs.

Inverted Perovskite Solar Cells with >85% Fill Factor via Sequential Interfacial Engineering

Even the most efficient inverted p–i–n architecture perovskite solar cells (PSCs) are still inferior to those with regular n–i–p architecture, which is mainly limited by interfacial loss. Herein, both wet and dry metal–halide perovskite films are regulated through organic molecules–assisted sequential interfacial engineering for high‐performance inverted PSCs. In specific, organic acetic acid treatment on the wet film potently regulates the nucleation and crystallization of perovskite films. Then, further loading 4‐(dimethylamino)benzoic acid on the dry perovskite film creates a passivating agent layer to suppress defect formation, leading to more phase‐pure and conductive perovskite films. Combined experimental and theoretical results illustrate that such sequential treatment is beneficial for decreasing surface trap states, non‐radiative recombination, and carrier transport loss. As a result, the target inverted PSC exhibits an unprecedented high fill factor (FF) of 85.31% together with a champion efficiency of 21.37%, which is greatly improved relative to the reference (FF of 79.60%, and efficiency of 19.40%). It should be noted that such a high FF is among the highest report and corresponding to 94.38% of the Shockley–Queisser limited FF (90.39%) of PSCs with a bandgap of 1.576 eV. In addition, the storage stability against moisture of target inverted PSCs is remarkably enhanced.

Green preparation of ginger-derived carbon dots accelerates wound healing

Inflammation is thought to impact the wound healing pathology and is highly related to many chronic wounds which do not heal. Natural derived herbs with anti-inflammation effects have gained attention with their availability and affordability for clinical treatment. In this study, the ginger (Zingiber officinale) -derived carbon dots (GCDs) were prepared by a green, fast, low-cost microwave-assisted hydrothermal approach at 180 °C by using ginger aqueous as the only precursor without any organic reagent or surface passivation agents. The GCDs showed a small size distribution with the mean particle size of 2.3 nm, enable emit intense blue photoluminescence and exhibited good biocompatibility. The GCDs was successfully applied in a bio-imaging in vitro. Accelerating wound healing by high anti-inflammatory activity was verified both in vivo and in vitro. Moreover, the GCDs effectively blocked the toll-like receptor 4 (TLR4)-mediated nuclear factor-kappa B (NFκB) pathway to significantly dephosphorylate IκBα and inhibited the nuclear translocation of p65 protein, which reduced the expression of proinflammatory factors. On the mRNA levels, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and Nitric oxide (NO) were decreased, and the inhibition rate were 51.6%, 81.7%, 86.0%, and 58.7%, respectively, all of which indicated excellent anti-inflammatory effect of the GCDs. Therefore, fluorescent GCDs have a promising application as an imaging tool and functional wound dressing for wound clinical management. The study also brings a new idea for the discovery of effective special substances that is not limited to bioactive small-molecule compounds.