Search Results (16)

Barium stannate (BaSnO₃) has emerged as a promising alternative electron transport material owing to its superior electron mobility, resistance to UV degradation, and energy bandgap tunability, yet BaSnO₃-based perovskite solar cells have not reached the efficiency levels of TiO₂-based designs. This theoretical study presents a design-driven evaluation of BaSnO₃-based perovskite solar cell architectures, incorporating MAPbI₃ or FAMAPbI₃ perovskite materials, Spiro-OMeTAD, or Cu₂O hole transport materials as well as hole-free configurations, under varying light intensity. Using a systematic device modelling approach, we explore the influence of key design variables—such as layer thickness, donor density, and interface defect concentration—of BaSnO₃ and operating temperature on the power conversion efficiency (PCE). Among the proposed designs, the FTO/BaSnO₃/FAMAPbI₃/Cu₂O/Au heterostructure exhibits an exceptionally effective arrangement with PCE of 38.2% under concentrated light (10,000 W/m², or 10 Sun). The structure also demonstrates strong thermal robustness up to 400 K, with a low temperature coefficient of −0.078% K⁻¹. These results underscore the importance of material and structural optimisation in PSC design and highlight the role of high-mobility, thermally stable inorganic transport layers—BaSnO₃ as the electron transport material (ETM) and Cu₂O as the hole transport material (HTM)—in enabling efficient and stable photovoltaic performance under high irradiance. The study contributes valuable insights into the rational design of high-performance PSCs for emerging solar technologies. Full article

Tumor-associated macrophages (TAMs) in the colorectal cancer (CRC) microenvironment promote tumor progression but can be reprogrammed into a pro-inflammatory state with anti-cancer properties. Activation of the G protein-coupled receptor 84 (GPR84) is associated with pro-inflammatory macrophage polarization, making it a potential target for CRC therapy. This study evaluates the effects of the GPR84 agonists 6-OAU and ZQ-16 on macrophage activation and anti-cancer efficacy. GPR84 expression on THP-1 macrophages and murine BMDMs was analyzed using flow cytometry. Macrophages were treated with 6-OAU or ZQ-16, and pro-inflammatory cytokine levels, reactive oxygen species (ROS) production, and phagocytosis were assessed using qPCR and functional assays. Anti-cancer effects were tested in a subcutaneous MC38 tumor model, with oral or intraperitoneal agonist administration. Pharmacokinetics and compound stability were also evaluated. In THP-1 macrophages, 6-OAU increased pro-inflammatory cytokines and ROS production, with ZQ-16 showing similar effects. However, neither agonist induced pro-inflammatory responses, ROS production, or phagocytosis in murine macrophages. In vivo, both agonists failed to inhibit tumor growth in the MC38 model despite systemic exposure. Current GPR84 agonists lack efficacy in promoting anti-cancer macrophage activity, limiting their potential as CRC therapies. Full article

Prostate-specific antigen (PSA) is a well-established tumour marker for prostatic carcinoma. In this study, we present a novel, real-time, and ultrasensitive Love-mode surface acoustic wave (L-SAW) immunosensor for PSA detection enhanced by MoS₂@Cu₂O-Au nanocomposite conjugation. The MoS₂@Cu₂O-Au nanocomposites were analyzed by SEM, XRD, and EDS. The experiments show a significant improvement in sensitivity and detection limit compared with the previous detection methods utilizing nanogold alone to detect PSA biomolecules. The experimental results show a good linear relationship when the range of PSA concentrations between 200 pg/mL and 5 ng/mL was tested. The experimental results also show good specificity against alpha 1 fetoprotein and L-tryptophan disruptors. Full article

Decades of research have illuminated the significant roles of gold/gold oxide clusters in small molecule catalytic oxidation. However, many fundamental questions, such as the actual sites to adsorb and activate O₂ and the impact of charge, remain unanswered. Here, we have utilized an improved genetic algorithm program coupled with the DFT method to systematically search for the structures of Au_1–5O_x^−/+/0 (x = 1–4) and calculated binding interactions between Au_1–5O_x^−/+/0 (x = 1–2) and O₂, aiming to determine the active sites and to elucidate the impact of different charge states in gold oxide systems. The results revealed that the reactivity of all three kinds of small gold oxide clusters toward O₂ is strongly site-dependent, with clusters featuring an -O-Au site exhibiting a preference for adsorption. The charges on small gold oxide clusters significantly impact the interaction strength and the activation degree of adsorbed O₂: in the case of anionic cluster, the interaction between O₂ and the -O-Au sites leads to a chemical reaction involving electron transfer, thereby significantly activating O₂; in neutral and cationic clusters, the adsorption of O₂ on their -O-Au sites can be viewed as an electrostatic interaction. Pointedly, for cationic clusters, the highly concentrated positive charge on the Au atom of the -O-Au sites can strongly adsorb but hardly activate the adsorbed O₂. These results have certain reference points for understanding the gold oxide interfaces and the improved catalytic oxidation performance of gold-based systems in the presence of atomic oxygen species. Full article

In this study, various factors affecting the efficiency of the MAPbI₃ perovskite solar cell (PSC) were analyzed using the SCAPS-1D simulation program. The basic device analyzed in this study had a structure of ITO/TiO₂/MAPbI₃/Cu₂O/Au. The thickness of each layer (electron transport layer (ETL), perovskite absorption layer (PAL), and hole transport layer (HTL)), PAL defect density and interface defect density were investigated as parameters. The optimized parameters that yielded the highest light conversion efficiency were an ETL (TiO₂) thickness of 100 nm, a PAL (MAPbI₃) thickness of 1300 nm, an HTL (Cu₂O) thickness of 400 nm, a PAL defect density of 10¹⁴ cm⁻³, and an interface defect density of 10¹³ cm⁻³ for both absorber/ETL and absorber/HTL interfaces. The optimized PSC exhibited a maximum efficiency of 19.30%. These results obtained in this study are expected to contribute considerably to the optimization and efficiency improvement of perovskite solar cells using inorganic charge-carrier transport layers. Full article

A Pb-free FASnI₃ perovskite solar cell improved by using Cu₂O/ZnO as two-dimensional-based hole/electron transport nanolayers has been proposed and studied by using a SCAPS-1D solar simulator. To calibrate our study, at first, an FTO/ZnO/MAPbI₃/Cu₂O/Au multilayer device was simulated, and the numerical results (including a conversion efficiency of 6.06%, an open circuit potential of 0.76 V, a fill factor parameter of 64.91%, and a short circuit electric current density of 12.26 mA/cm²) were compared with the experimental results in the literature. Then, the conversion efficiency of the proposed FASnI₃-based solar cell was found to improve to 7.83%. The depth profile energy levels, charge carrier concentrations, recombination rate of electron/hole pair, and the FASnI₃ thickness-dependent solar cell efficiency were studied and compared with the results obtained for the MAPbI₃-containing device (as a benchmark). Interestingly, the FASnI₃ material required to obtain an optimized solar cell is one-half of the material required for an optimized MAPbI₃-based device, with a thickness of 200 nm. These results indicate that developing more environmentally friendly perovskite solar cells is possible if suitable electron/hole transport layers are selected along with the upcoming Pb-free perovskite absorber layers. Full article

The use of heterogeneous photocatalysis in biologically contaminated water purification processes still requires the development of materials active in visible light, preferably in the form of thin films. Herein, we report nanotube structures made of TiO₂/Ag₂O/Au⁰, TiO₂/Ag₂O/PtO_x, TiO₂/Cu₂O/Au⁰, and TiO₂/Cu₂O/PtO_x obtained via one-step anodic oxidation of the titanium-based alloys (Ti₉₄Ag₅Au₁, Ti₉₄Cu₅Pt₁, Ti₉₄Cu₅Au₁, and Ti₉₄Ag₅Pt₁) possessing high visible light activity in the inactivation process of methicillin-susceptible S. aureus and other pathogenic bacteria—E. coli, Clostridium sp., and K. oxytoca. In the samples made from Ti-based alloys, metal/metal oxide nanoparticles were formed, which were located on the surface and inside the walls of the NTs. The obtained results showed that oxygen species produced at the surface of irradiated photocatalysts and the presence of copper and silver species in the photoactive layers both contributed to the inactivation of bacteria. Photocatalytic inactivation of E. coli, S. aureus, and Clostridium sp. was confirmed via TEM imaging of bacterium cell destruction and the detection of CO₂ as a result of bacteria cell mineralization for the most active sample. These results suggest that the membrane ruptures as a result of the attack of active oxygen species, and then, both the membrane and the contents are mineralized to CO₂. Full article

In any utopic vision of the international refugee protection regime at least these two conditions ought to prevail: (1) all those who are genuinely in need of refugee protection will be granted international protection; (2) all those who are responsible for criminality, especially, serious international crimes, shall be held criminally liable. This presumes that the so-called “exclusion clauses” of the 1951 Refugee Convention, Article 1F, and those found in the regional refugee rights instruments (1969 OAU Convention, 1984 Cartagena Declaration, 2011 EU Qualifications Directive) are not required. No one would be excluded from refugee protection who meets the definition of refugee as found in these international refugee rights instruments. By the same token, anyone who is responsible for serious criminality, especially, serious international crimes, (as defined by the 1998 Rome Statute of the International Criminal Court) shall be held criminally liable. This serves the ideal of bringing an end to impunity for serious international criminality and ensuring everyone is held accountable for their contribution for the persecution of others. Accordingly, the first part of this article presents the thesis that serious criminality should be part of the inclusionary portions of the definition of who is a refugee and not its exclusionary portions, Article 1F of the 1951 Refugee Convention. Indeed, Article 1F, it is argued, is antiquated and no longer conforms to contemporary international norms and principles and can result in injustices to refugee applicants. Given the inherent complexity and difficulties with Article 1F and the fact it is no longer required, it can be repealed and Article 1A(2), the definition of who is a refugee, can be amended to not include anyone who is responsible for the commission of serious criminality. Moreover, when there is sufficiently reliable and trustworthy evidence that a refugee applicant is responsible for serious criminality then they can be prosecuted and by doing so both ending impunity for serious international crimes and advancing international justice can be achieved. The second part of the article is a commentary on the first part and raises a word of caution. The thesis of this part is that before adopting any radical solution with respect to the exclusion clause, it would be useful to provide a broader context to the issues raised. The commentary raises some questions regarding the underlying assumptions in the first part, specifically, in its examination of the human rights and international criminal justice framework. These questions are on three levels, namely conceptual, legal, and practical. The commentary concludes with some overarching observations in respect to the criticisms raised and the proposal submitted. Full article

Accurate urban morphology provided by Local Climate Zones (LCZ), a universal surface classification scheme, offers opportunities for studies of urban heat risk, urban ventilation, and transport planning. In recent years, researchers have attempted to generate LCZ maps worldwide with the World Urban Database and Access Portal Tools (WUDAPT). However, the accuracy of LCZ mapping is not satisfactory and cannot fulfill the quality demands of practical usage. Here, we constructed a high-quality sample dataset from Chinese cities and presented a patch-based classification framework that employs chessboard segmentation and multi-seasonal images for LCZ mapping. Compared with the latest WUDAPT method, the overall accuracy for all LCZ types (OA) and urban LCZ types (OA_u) of our framework increased by about 10% and 9%, respectively. Furthermore, based on the analysis of population distribution, we first gave the population density of different built-up LCZs of Chinese cities and found a hierarchical effect of population density among built-up LCZs in different size cities. In summary, this study could serve as a valuable reference for producing high-quality LCZ maps and understanding population distribution patterns in built-up LCZ types. Full article

We propose an ultrasensitive leaky surface acoustic wave (LSAW) immunosensor based on molybdenum disulfide @ cuprous oxide—gold (MoS₂@Cu₂O-Au) nanoparticles and subsequent gold staining for the detection of alpha-fetoprotein (AFP). MoS₂@Cu₂O-Au nanoparticles, with their large specific surface area and good biocompatibility, not only capture the secondary antibodies (Ab₂) but also amplify the mass loading effect of the acoustic wave sensor in the detection of AFP. The immunosensor signals are further amplified upon injection of gold staining solution. The developed immunosensor achieved a low detection limit of 5.5 and 25.0 pg/mL with and without gold staining, respectively. The immunosensor demonstrated its efficiency for the quantitative detection of AFP in complex biological fluids, including human serum and saliva samples, with excellent selectivity and long-term stability, showing great potential for the quantification of AFP in clinical diagnosis. Full article

In the last decade, perovskite solar cells have made a quantum leap in performance with the efficiency increasing from 3.8% to 25%. However, commercial perovskite solar cells have faced a major impediment due to toxicity and stability issues. Therefore, lead-free inorganic perovskites have been investigated in order to find substitute perovskites which can provide a high efficiency similar to lead-based perovskites. In recent studies, as a kind of lead-free inorganic perovskite material, Cs₄CuSb₂Cl₁₂ has been demonstrated to possess impressive photoelectric properties and excellent environmental stability. Moreover, Cs₄CuSb₂Cl₁₂ nanocrystals have smaller effective photo-generated carrier masses than bulk Cs₄CuSb₂Cl₁₂, which provides excellent carrier mobility. To date, there have been no reports about Cs₄CuSb₂Cl₁₂ nanocrystals used for making solar cells. To explore the potential of Cs₄CuSb₂Cl₁₂ nanocrystal solar cells, we propose a lead-free perovskite solar cell with the configuration of FTO/ETL/Cs₄CuSb₂Cl₁₂ nanocrystals/HTL/Au using a solar cell capacitance simulator. Moreover, we numerically investigate the factors that affect the performance of the Cs₄CuSb₂Cl₁₂ nanocrystal solar cell with the aim of enhancing its performance. By selecting the appropriate hole transport material, electron transport material, thickness of the absorber layer, doping densities, defect density in the absorber, interface defect densities, and working temperature point, we predict that the Cs₄CuSb₂Cl₁₂ nanocrystal solar cell with the FTO/TiO₂/Cs₄CuSb₂Cl₁₂ nanocrystals/Cu₂O/Au structure can attain a power conversion efficiency of 23.07% at 300 K. Our analysis indicates that Cs₄CuSb₂Cl₁₂ nanocrystals have great potential as an absorbing layer towards highly efficient lead-free all-inorganic perovskite solar cells. Full article

Cuprous oxide (Cu₂O) homojunction thin films on Ti substrates were fabricated by an electrochemical deposition in which a p-Cu₂O layer was deposited on an n-Cu₂O layer by carefully controlled bath conditions. It was found that the open-circuit voltage of the homojunction solar cell was significantly influenced by the pH of the lactate bath. The variation of the pH was used to achieve the best possible crystal orientation for homojunctions. The crystallinity and morphology of the products were characterized by X-ray diffraction (XRD), high-energy x-ray diffraction (HEXRD), and scanning electron microscopy (SEM). The current density voltage (J-V) analysis showed that the sulfur treatment and annealing enhanced the photocurrent by ten-fold compared to the untreated and unannealed homojunction solar cell. X-ray photoelectron spectroscopy (XPS) studies confirmed that the sulfur treatment eliminated the surface CuO and formed a thin layer of CuS, which was very useful to make the front Ohmic contact. Transient measurements confirmed that the p-type Cu₂O layer, which was subjected to sulfur treatment, significantly reduced the recombination, thus enhancing the efficiency of the solar cell. The best sulfur treated annealed Ti/n-Cu₂O/p-Cu₂O/Au solar cell produced an energy conversion efficiency of 2.64% with an open-circuit voltage of 490 mV and a short circuit current density of 12.8 mA cm⁻² under AM 1.5 illumination. Full article

Hydrogen production by photoreforming of biomass-derived ethanol is a renewable way of obtaining clean fuel. We developed a site-specific deposition strategy to construct supported Au catalysts by rationally constructing Ti³⁺ defects inTiO₂ nanorods and Cu₂O-TiO₂ p-n junction across the interface of two components. The Au nanoparticles (~2.5 nm) were selectively anchored onto either TiO₂ nanorods (Au@TiO₂/Cu₂O) or Cu₂O nanocubes (Au@Cu₂O/TiO₂) or both TiO₂ and Cu₂O (Au@TiO₂/Cu₂O@Au) with the same Au loading. The electronic structure of supported Au species was changed by forming Au@TiO₂ interface due to the adjacent Ti³⁺ defects and the associated oxygen vacancies while unchanged in Au@Cu₂O/TiO₂ catalyst. The p-n junction of TiO₂/Cu₂O promoted charge separation and transfer across the junction. During ethanol photoreforming, Au@TiO₂/Cu₂O catalyst possessing both the Au@TiO₂ interface and the p-n junction showed the highest H₂ production rate of 8548 μmol g_cat⁻¹ h⁻¹ under simulated solar light, apparently superior to both Au@TiO₂ and Au@Cu₂O/TiO₂ catalyst. The acetaldehyde was produced in liquid phase at an almost stoichiometric rate, and C−C cleavage of ethanol molecules to form CH₄ or CO₂ was greatly inhibited. Extensive spectroscopic results support the claim that Au adjacent to surface Ti³⁺ defects could be active sites for H₂ production and p-n junction of TiO₂/Cu₂O facilitates photo-generated charge transfer and further dehydrogenation of ethanol to acetaldehyde during the photoreforming. Full article

The electrochemical formation of nanostructured materials is a cost effective route to creating substrates that can be employed in a variety of applications. In this work the surface of a copper electrode was electrochemically restructured in an alkaline solution containing ethanol as an additive to modify the surface morphology, and generate a Cu/Cu₂O surface, which is known to be active for the electrocatalytic reduction of environmentally harmful nitrate ions. To increase the activity of the nanostructured surface it was decorated with gold prisms through a facile galvanic replacement approach to create an active Cu/Cu₂O/Au layer. The surface was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, as well as electrochemical techniques. It was found that the presence of recalcitrant oxides, and Au was beneficial for the increased activity compared to unmodified copper and undecorated restructured copper and was consistent with the incipient hydrous oxide adatom mediator model of electrocatalysis. This approach to generating nanostructured metal/metal oxide surfaces that can be galvanically replaced to create these types of composites may have other applications in the area of electrocatalysis. Full article

The unprecedented current “refugee crisis,” with its 65 million plus uprooted people, demands a new protection orientation and framework for refugees and other forced migrants that are focused on the “root causes” of refugeehood, non-international protracted armed conflict or civil war. It is argued that four essential reforms are required to the international refugee protection system to respond to the “root causes” of refugees in the world today. The first calls for broadening the definition of who is a refugee to include “war refugees” as found in the 1984 Cartagena Declaration and the 1969 Organization of African Unity (OAU) Convention. The 1984 Cartagena Declaration is preferred because it has the most progressive and broadest legal definition of who is a refugee and, therefore, should be emulated by all regions and the UNHCR internationally. The second reform would be the adoption of the Cartagena Declaration decennial consultation process and its comprehensive Plan of Action by the UNHCR on a global basis. This process has proven to be a success in Latin America and ought to be adopted internationally to develop and to realize the progressive advancement of international protection for all persons who are fleeing persecution and armed conflict. The third major reform is to develop the capacity of the UN to be able to operate in the midst of an armed conflict situation in order to broker a ceasefire and, then, negotiate a peace agreement, particularly, in those situations where massed forced displacement has taken place or potentially could take place. The fourth reform calls for the UN to expand the Responsibility to Protect (R2P) doctrine to incorporate massed forced displacement, in addition to, war crimes, crimes against humanity, ethnic cleansing, and, genocide. This further implies that mass forced displacement ought to be criminalized and made a serious international crime, not simply in the international humanitarian law and international criminal law sense of forced deportation, transfers, and expulsions, by opposing military forces, but in situations of armed conflict when people flee of their own volition in order to save their lives. These four reforms do not require a reformulation or reconceptualization of the international refugee protection system but a reform of a number of key elements that would simultaneously address the “root causes” of refugees and, especially, mass forced displacement that is due principally to non-international protracted armed conflict or seemingly endless civil wars. Full article