Reduced Surface Defects Research Articles

Surface Defects Management by In Situ Etching with Methanol for Efficient Inverted Inorganic Perovskite Solar Cells

AbstractInorganic perovskite solar cells (IPSCs) have developed rapidly due to their good thermal stability and the bandgap suitable for perovskite/silicon tandem solar cells. However, the large open‐circuit voltage (VOC) deficit derived from the surface defects and the energy level structure mismatch impede the development of device performance, especially in the P‐I‐N structure IPSCs. Herein, an innovative in situ etching (ISE) treatment method is proposed to reduce surface defects through methanol without additional passivator. It is found that the perovskite films treated with methanol result in a slight excess of PbI2 on the surface and inserted into the grain boundaries. Therefore, the successful decrease of surface defects by methanol and the passivation of grain boundary defects by PbI2 greatly reduce the trap density of perovskite films. And the larger work function of PbI2 contributes to the energy band of perovskite surface bending downward and forms gradient energy level alignment at the I/N interface, which accelerates extraction of charge carriers. As a result, the efficiency of CsPbI2.85Br0.15 inverted IPSC is enhanced from 16.00% to 19.34%, which is one of the mostly efficient IPSCs. This work provides an original idea without additional passivator to manage the defects of inorganic perovskite.

One stone two birds: Pitch assisted microcrystalline regulation and defect engineering in coal-based carbon anodes for sodium-ion batteries

Coal-based carbons with abundant resources and low cost are regarded as promising anode materials for sodium‐ion batteries (SIBs). However, their ordered carbon microstructure and abundant surface defects often result in low Na-storage capacity and poor initial coulombic efficiency (ICE). Herein, we propose a simple vapor deposition strategy to synthesize coal-based carbons coated with pitch-based soft carbon layer (PCLC) for potential use as anodes for SIBs. The deposition of pitch-based volatile species allows for an efficient cross-linking reaction between hydroxyl‑containing volatile species and oxygen-rich functional groups of coal, thus generating a disordered inner-phase microcrystalline structure with dominant pseudo-graphitic phase in coal-derived carbon. Meanwhile, the exterior soft carbon coating layer substantially reduces surface defects and increases the electrical conductivity of coal-based carbon. Unlike the pristine lignite coal pyrolytic carbon which exhibited a Na-storage capacity of 290.2 mAh g−1 and ICE of 59.9%, the optimal PCLC (PCLC-1) delivered a higher reversible capacity of 312.2 mAh g−1 and a much-improved ICE of 85.3%. In addition, the PCLC-1 electrode also demonstrated excellent cycle stability with 93.4% retention after 1,000 cycles. When coupled with O3-NaNi1/3Fe1/3Mn1/3O2 cathode, PCLC-1 as an anode in a full cell configuration achieved a high energy density of 220.9 Wh kg−1 with excellent cycling and rate performance. The proposed work offers a unique insight into modulating the microcrystalline structure and surface chemistry of high-performance coal-based carbon anode materials for commercial SIBs.

Passivation of Surface Defects by X-type Short-Chain Ligands for High Quantum Yield and Stable CsPbX3 Quantum Dots Synthesis and Application in WLEDs

All-inorganic CsPbX3 perovskite quantum dots have excellent optoelectronic properties and are excellent candidates for optoelectronic applications. However, the surface ligands (oleyl ammonium, oleic acid) commonly used in traditional inorganic perovskite quantum dots easily fall off from the quantum dots and their protective power is relatively weak, resulting in poor quantum yield and stability of the quantum dots, limiting their application. In this paper, we introduce an X-type short-chain ligand (DDEAB) passivation strategy to enhance the optoelectronic properties of CsPbX3 quantum dots through a facile room-temperature synthesis method and the strong affinity of X-type ligands for surface atoms. The results of TRPL and X-ray photoelectron spectroscopy showed longer lifetime and stronger surface affinity. This result confirms that didecyldimethylammonium bromide (DDEAB) has better binding to CsPbBr3 QDs and can effectively reduce surface defects and improve quantum yield. As a result, the introduction of short-chain ligands can more effectively passivate the surface halogen defects of CsPbX3 QDs, achieving high quantum yield (>90%) and long-term storage environmental stability. In addition, DDEAB-passivated CsPbBr3 QDs have been successfully applied in white light emitting diodes (WLEDs) with wider color gamut (123%), and good EL stability compared to NTSC TV color standard. Our proposed short-chain ligand DDEAB passivation strategy may provide a reference guideline for the preparation of quantum dots and photovoltaic devices with high photoluminescence and environmental stability.

Surface polarization-induced emission and stability enhancement of CsPbX3 nanocrystals.

Recently, the polarization effect has been receiving tremendous attention, as it can result in improved stability and charge transfer efficiency of metal-halide perovskites (MHPs). However, realizing the polarization effect on CsPbX3 NCs still remains a challenge. Here, metal ions with small radii (such as Mg2+, Li+, Ni2+, etc.) are introduced on the surface of CsPbX3 NCs, which facilitate the arising of electric dipole and surface polarization. The surface polarization effect promotes redistribution of the surface electron density, leading to reinforced surface ligand bonding, reduced surface defects, near unity photoluminescence quantum yields (PLQYs), and enhanced stability. Moreover, further introduction of hydroiodic acid results in the in situ formation of tert-butyl iodide (TBI), which facilitates the successful synthesis of pure iodine-based CsPbI3 NCs with high PLQY (95.3%) and stability under ambient conditions. The results of this work provide sufficient evidence to exhibit the crucial role of the surface polarization effect, which promotes the synthesis of high-quality MHPs and their applications in the fields of optoelectronic devices.

Investigation of in situ sulfide/nitride/phosphide treatments of hematite photoanodes for improved solar water oxidation.

Surface catalyst engineering can effectively improve the photoelectrochemical water splitting (PEC-WS) performance of semiconductor photoelectrodes. In situ surface functional treatments can effectively reduce interface defects and improve photogenerated carrier transport. In this study, FTO/Sn@α-Fe2O3/FeOOH photoanodes were modified with in situ sulfide/nitride/phosphide treatments to improve their PEC-WS performance. Compared with the pure α-Fe2O3 photoanode, the photocurrent densities of FTO/Sn@α-Fe2O3/FeOOH photoanodes after sulfide/nitride/phosphide treatments increased from 0.88 to 3.38 mA cm-2 at 1.23 VRHE. The onset potential showed a cathode shift of 0.1 V. Photoelectrochemical analyses and theoretical calculation demonstrated that the surface engineering by sulfide/nitride/phosphide treatments can significantly reduce surface defects, enhance electrical conductivity and promote photogenerated carrier separation and transfer efficiency by regulating interface charge transfer, binding energy and internal electric field. The formation of an FeSx catalyst and N/P coordination complexes in the sulfide/nitride/phosphide processes on the surface of α-Fe2O3 photoanodes can effectively reduce photogenerated carrier recombination. This work provides experimental and theoretical support for surface structure design and improved photoelectric conversion performance of semiconductor photoelectrode materials.

Hard carbon anodes derived from phenolic resin/sucrose cross‐linking network for high‐performance sodium‐ion batteries

AbstractHard carbons are widely studied as anode materials for sodium‐ion batteries (SIBs) due to their high Na‐storage capacity, long cycle life, and low cost. However, the low initial coulombic efficiency (ICE) and poor cycle performance remain bottleneck concerns that necessitate a comprehensive material engineering solution. Herein, we propose a facile strategy to synthesize amorphous carbons with pseudo‐graphitic dominated crystalline, expanded interlayer spacing, and reduced surface defects via carbonization of the cross‐linking network of phenolic resin and sucrose. An elaborate structural and electrochemical characteristics analysis has been investigated against different sucrose contents and carbonization temperatures. The representative PF‐S‐55‐1200 with the optimum cross‐linking degree as well as carbonization temperature realizes a high reversible Na‐storage capacity of 323.0 mAh g−1 with an ICE as high as 86.4%, much superior to the pristine phenolic resin pyrolytic carbon with a capacity of 267.1 mAh g−1 and an ICE of 46.3%. The hybrid hard carbons also exhibit robust structural stability with a prolonged cycle lifespan evidenced by a retained capacity of 238.3 mAh g−1 at a current density of 200 mA g−1 over 1500 cycles. The proposed route promises low‐cost and high‐performance hybrid hard carbons with optimized structural configuration for advanced SIBs.

Self-Assembled Biomolecule Interlayer for Enhanced Efficiency and Stability of Inverted Organic Solar Cells

Interlayers play a vital role in achieving high efficiency and stability of organic solar cells (OSCs). Zinc oxide (ZnO) has been widely used as an electron transport layer (ETL) in inverted OSCs; however, its high structural defects and intrinsic photocatalytic nature toward nonfullerene acceptors limit its applications in OSCs. Herein, a low-cost, environmentally-friendly biomolecule, potassium aspartic acid (PAA), is introduced as the interlayer on top of the ZnO ETL. Through experimental results and theoretical calculations, we find PAA not only can tune energy alignments and passivate oxygen vacancy defects and zinc interstitial dangling bonds but also can promote the π–π stacking strength of the active layer, leading to enhanced charge collection and photovoltaic performance in both IT series (e.g., PM6:IT-4F) and Y series (e.g., PM6:BTP-4F-C5-16) OSCs. Moreover, benefiting from the reduced surface defects of ZnO, OSCs based upon the ZnO/PAA ETL exhibit superior stabilities under continuous operation as well as UV-light irradiation, leading to an improved T80 lifetime of around 4 times compared to OSCs fabricated without the PAA interlayer. This work provides a universal solution to fabricate efficient and stable inverted OSCs.

Vitamins as Active Agents for Highly Emissive and Stable Nanostructured Halide Perovskite Inks and 3D Composites Fabricated by Additive Manufacturing

AbstractThe use of non‐toxic and low‐cost vitamins like α‐tocopherol (α‐TCP, vitamin E) to improve the photophysical properties and stability of perovskite nanocrystals (PNCs), through post‐synthetic ligand surface passivation, is demonstrated for the first time. Especially interesting is its effect on CsPbI3 the most unstable inorganic PNC. Adding α‐TCP produces that the photoluminescence quantum yield (PLQY) of freshly prepared and aged PNCs achieves values of ≈98% and 100%, respectively. After storing 2 months under ambient air and 60% relative humidity, PLQY is maintained at 85% and 67%, respectively. α‐TCP restores the PL features of aged CsPbI3 PNCs, and mediates the radiative recombination channels by reducing surface defects. In addition, the combination of α‐TCP and PNCs facilitates the chemical formulation to prepare PNCs‐acrylic polymer composites processable by additive manufacturing. This enables the development of complex shaped parts with improved luminescent features and long‐term stability for 4 months, which is not possible for non‐modified PNCs. A PLQY ≈92% is reached in the 3D printed polymer/PNC composite, the highest value obtained for a red‐emitting composite solid until now as far as it is known. The passivation shell provided by α‐TCP makes that PNCs inks do not suffer any degradation process avoiding the contact with the environment and preserve their properties after reacting with polar monomers during composite polymerization.

A novel strategy for designing Fe-Ni gradient multilayer coatings using laser-assisted electrodeposition and regulation mechanism

This study proposed a new process strategy to obtain Fe-Ni multilayer gradient structure. Laser irradiation was introduced into the electrochemical deposition (ECD) process. Based on activation and diffusion control steps, the regulation of element content is realized by adjusting laser parameters. In addition, the surface quality, internal structure, and performance of the coating prepared by laser-assisted ECD were evaluated. The results show that laser irradiation can reduce surface defects and roughness without changing the internal structure. Laser irradiation improves the uniformity of element content distribution and reduces the Fe content. In the same deposition time, the coating's thickness increased by approximately 91.2 %. The element content delamination was successfully achieved by changing the laser parameters without changing the electrochemical parameters. The main mechanism is that laser irradiation increases the limiting current density and inhibits diffusion control. Compared with monolithic ECD coatings, the mechanical properties and corrosion resistance are improved. According to the control mechanism, the preparation of gradient structures along the horizontal direction of the substrate is verified.

Effects of machining parameters on enhancing Alpha-Beta Titanium alloy using Taguchi-grey relational analysis for aerospace applications

The need for enhancement of productivity and quality of the machined titanium alloy components is paramount to meet the high demands of aerospace parts. Various optimization techniques are being used widely to find suitable machining parameters to improve productivity and reduce surface defects. The present study aims to derive an optimal combination of process parameters during the end milling operation of Ti-6Al-4V alloy for enhancing performance measures which are surface roughness, specific cutting energy and material removal rate (MRR). The Grey relational optimization techniques along with Taguchi method has been utilized for finding the optimum machining parameters. It has been found that the axial depth of cut has the most significant factor on machining characteristics in end milling process of titanium alloy. Using Taguchi-Grey relational analysis technique, optimal process parameter combination has been computed and the performance enhancement using the optimal process combination has been verified by the confirmation test

Secondary Anti-Solvent Treatment for Efficient 2D Dion-Jacobson Perovskite Solar Cells.

Surface defects-mediated nonradiative recombination plays a critical role in the performance and stability of perovskite solar cells (PSCs) and surface post-treatment is widely used for efficient PSCs. However, the commonly used surface passivation strategies are one-off and the passivation defect ability is limited, which can only solve part of the defects in the topmost surface area. Here, a secondary anti-solvent strategy is proposed to further reduce surface defects based on conventional surface passivation for the first time. Based on this, the crystallization quality of 2D Dion-Jacobson perovskite is enhanced and the surface defects density is further reduced by nearly two orders. In addition, a gradient structure of perovskite with n= 2 phases located at the top of the film and 3D-like phases located at the bottom of the film can also be obtained. The modulated perovskite film boosts the efficiency of 2D perovskites (n= 5) up to 19.55%. This strategy is also very useful in other anti-solvent processed perovskite dipping systems, which paves a promising avenue for minimizing surface defects toward highly efficient perovskite devices.

In Situ Bonding Regulation of Surface Ligands for Efficient and Stable FAPbI3 Quantum Dot Solar Cells.

Quantum dots (QDs) of formamidinium lead triiodide (FAPbI3 ) perovskite hold great potential, outperforming their inorganic counterparts in terms of phase stability and carrier lifetime, for high-performance solar cells. However, the highly dynamic nature of FAPbI3 QDs, which mainly originates from the proton exchange between oleic acid and oleylamine (OAm) surface ligands, is a key hurdle that impedes the fabrication of high-efficiency solar cells. To tackle such an issue, here, protonated-OAm in situ to strengthen the ligand binding at the surface of FAPbI3 QDs, which can effectively suppress the defect formation during QD synthesis and purification processes is selectively introduced. In addition, by forming a halide-rich surface environment, the ligand density in a broader range for FAPbI3 QDs without compromising their structural integrity, which significantly improves their optoelectronic properties can be modulated. As a result, the power conversion efficiency of FAPbI3 QD solar cells (QDSCs) is enhanced from 7.4% to 13.8%, a record for FAPbI3 QDSCs. Furthermore, the suppressed proton exchange and reduced surface defects in FAPbI3 QDs also enhance the stability of QDSCs, which retain 80% of the initial efficiency upon exposure to ambient air for 3000 hours.

Analysis on the impact of recycled ceramic waste, fiber format, and manufacturing techniques on polymer composite properties

Dumping of construction waste is a growing issue in current situation and recycling and reusing are the suitable solutions for solving it. This effort aims to recycle and reuse of ceramic construction waste. This work examines the effects of inclusion of waste tile powder, change in the glass fiber form which was used as a reinforcement, and method of manufacturing method the polymer composite on the properties of the composite. Normal glass-reinforced polymer composites have good tensile, flexural, and toughness properties. The three forms of glass fibers used for the study includes, chopped fiber mat, glass fiber mesh, and woven glass fiber. Fillers are added to improve hardness and tribology related attributes. Composite fabrication was carried out by conventional hand layup, room temperature compression molding, and hot compression molding process. The goal is to harden the composite without reducing the tensile strength of the composite. ASTM D3039, ASTM D2240, and ASTM D570–98 procedures were adapted for measuring tensile, hardness and water intake properties respectively. Characterization was done through SEM image analysis. A result of 160.21 MPa tensile strength, Shore D hardness value of 96.7, and water absorption of 0.71 percent after 24 h of testing was recorded. Adding waste tile powder to the polymer composite increases its hardness and reduces surface defects without affecting tensile properties. Fiber form and manufacturing method also affect the output to some extent. The effect of water absorption on the hardness property of the composite was checked and found to be negligible which makes it durable and reliable to be used in moist environments. This composite can be used in automotive parts, moist environment, window and door frames, and in electrical panels.

24.20%-Efficiency MA-Free Perovskite Solar Cells Enabled by Siloxane Derivative Interface Engineering.

Suppressing defects at the interface between the TiO2 electron transport layer (ETL) and perovskite film is critical for high efficiency and stable perovskite solar cells (PSCs). Herein, a siloxane derivative diethylphosphatoethylsilicic acid (PSiOH) is developed to modify the interface of TiO2 ETL/FA0.83 Cs0.17 PbI3 perovskite. Comprehensive characteristics reveal that silicon hydroxyl (SiOH) in PSiOH can reduce surface defects, improve the electrical propertiesand optimize the energy band structure of TiO2 by forming a SiOTi bond, while the phosphate bond (PO) in PSiOH can passivate Pb-related defects on the perovskite bottom surface. Consequently, PSiOH-modified PSCs yield a remarkable power conversation efficiency of 24.20% and improved air, thermal, or illumination stabilities. This study provides insight into passivation defects at the buried interface for efficient and stable PSCs.

Formation and Deformation Mechanism of Mountain‐Like Surface Crack on the Hot‐Rolled Thick Plate of HSLA Steel

Mountain‐like surface cracks often appear on the thick plates of high‐strength low‐alloy (HSLA) steel after hot rolling, which have a serious impact on production efficiency. Herein, the formation cause of mountain‐like cracks is discussed using methods such as acid pickling and observations of microstructure and inclusions. The deformation behavior of microcracks is obtained by analyzing the rolling process of slab. The inclusions in the top of the crack are Type‐I inclusions with high elemental contents of K and P and Type‐II inclusions with high elemental contents of C. The inclusions in the sides of the crack are Al2O3. It is concluded that mountain‐like cracks are caused by surface microcracks containing Type‐I inclusions in the continuous casting slab. During rolling, the rapid deforming of side‐1 stretches the crack so that the unusual microstructure appears. The cracks extended in the rolling direction have Al2O3 inclusions. The mountain‐like crack with Type‐I inclusions in the top and Al2O3 in the sides eventually form. A single microcrack forms a single mountain‐like crack and multiple clustered microcracks form a continuous mountain‐like crack. To reduce mountain‐like cracks, reducing Type‐I inclusions to reduce surface defects of the slab is an effective means.

Improving the Efficiency of Organic Solar Cells with Methionine as Electron Transport Layer.

Interface modification is an important way to get better performance from organic solar cells (OSCs). A natural biomolecular material methionine was successfully applied as the electron transport layer (ETL) to the inverted OSCs in this work. A series of optical, morphological, and electrical characterizations of thin films and devices were used to analyze the surface modification effects of methionine on zinc oxide (ZnO). The analysis results show that the surface modification of ZnO with methionine can cause significantly reduced surface defects for ZnO, optimized surface morphology of ZnO, improved compatibility between ETL and the active layer, better-matched energy levels between ETL and the acceptor, reduced interface resistance, reduced charge recombination, and enhanced charge transport and collection. The power conversion efficiency (PCE) of OSCs based on PM6:BTP-ec9 was improved to 15.34% from 14.25% by modifying ZnO with methionine. This work shows the great application potential of natural biomolecule methionine in OSCs.

CuBiSe2 Quantum Dots as Ecofriendly Photosensitizers for Solar Cells

Cu-based ternary chalcogenides have shown high promise as low-cost ecofriendly alternatives to heavy-metal based photosensitizers. The successive ionic layer adsorption and reaction (SILAR) processed CuBiSe2 quantum dots possess an optimal bandgap, appealing photoresponsivity (excellent absorption coefficient of (10)5 cm–1), and photostability. Because of these advantageous properties, they have been investigated as photoabsorber materials for solar cells in this work for the first time. Use of such nontoxic and nonscarce materials, paired with low-temperature solution processing can address both concerns of environmental regulation and fabrication costs. The performance of the prototype solar cell developed has been satisfactory as a new emerging material (power conversion efficiency (PCE) of 2%) unlike the reported CuBiS2 showing a PCE of 0.68%. A further increase in efficiency was observed with the formation of a heterostructure CuBiSe2/CuBiS2 that exhibits a type-1 heterostructure and enables improvement in power conversion efficiency up to 2.6%. CuBiS2 acts as a passivation layer (reducing surface defects and recombination losses) and also as an absorber, facilitating confinement and longer lifetime of charge careers. A detailed investigation of these Cu based selenium quantum dots and the insights provided into their electronic structure and dynamics in this work would significantly influence the future research of these materials into other optoelectronic applications.

Fluorinated Interlayer Modulation of NiOx-Based Inverted Perovskite Solar Cells.

p-Type inorganic nickel oxide (NiOx) exhibits high transparency, tunable-optoelectronic properties, and a work function (WF) that is potentially suitable for hole extraction in inverted perovskite solar cells (PSCs). However, NiOx films possess surface defects that lead to high interfacial recombination and an energy offset with the ionization potential of the perovskite. Herein, we show that fluorinated 3-(2,3,4,5,6-pentafluorophenyl)propan-1-aminium iodide (FPAI) can be used to modify the electronic properties of the NiOx anode interlayer. The FPAI modification led to good perovskite crystal growth and films with reduced surface defects. The FPAI modification also increased the WF of NiOx and improved charge extraction. These improvements led to an increased Voc value compared with control devices without FPAI modification, 1.05 V versus 1.00 V, and a higher short-circuit current and larger fill factor. As a result, the best PSCs with FPAI-modified NiOx had a power conversion efficiency of 19.3%. Finally, the PSCs with the FPAI-modified NiOx layer were found to have improved stability.

A comprehensive review on surface quality improvement methods for additively manufactured parts

PurposeThe purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the products manufactured using AM usually suffer from defects like roughness or uneven surfaces. This paper discusses the various surface quality improvement techniques, including how to reduce surface defects, surface roughness and dimensional accuracy of AM parts.Design/methodology/approachThere are many different types of popular AM methods. Unfortunately, these AM methods are susceptible to different kinds of surface defects in the product. As a result, pre- and postprocessing efforts and control of various AM process parameters are needed to improve the surface quality and reduce surface roughness.FindingsIn this paper, the various surface quality improvement methods are categorized based on the type of materials, working principles of AM and types of finishing processes. They have been divided into chemical, thermal, mechanical and hybrid-based categories.Research limitations/implicationsThe review has evaluated the possibility of various surface finishing methods for enhancing the surface quality of AM parts. It has also discussed the research perspective of these methods for surface finishing of AM parts at micro- to nanolevel surface roughness and better dimensional accuracy.Originality/valueThis paper represents a comprehensive review of surface quality improvement methods for both metals and polymer-based AM parts.Graphical abstract of surface quality improvement methods

C3N4 and C3N5 Nanosheets As Passivation Layers and Carrier Extractors for Inorganic Semiconductor Nanowires and Quantum Dots

Inorganic semiconductor nanowires and quantum dots made of chalcogenides, III-V semiconductors and halide perovskites offer exciting potential for optoelectronic devices. The orthogonalization possible in nanowires between the normally competing processes of charge generation and charge separation have been used to project very high operating performance exceeding that of thin films and single crystals in light harvesting devices such as solar cells, photodetectors, photocatalysts and photoelectrolyzers. Likewise, inorganic quantum dots with size-tunable absorption and emission spectra are excellent candidates for light emitting devices as well as light harvesting devices. However, the practical performance of inorganic nanowire based optoelectronic devices has significantly lagged theoretical predictions. A major reason for the discrepancy between theory and experiment is the presence of surface traps and defects in nanowires and quantum dots, which exhibit a large surface area to volume ratio. Several chemical treatments and annealing regimens have been employed to heal surface defects in nanowires and quantum dots. One popular strategy involves wrapping nanowires and/or quantum dots with a thin coating of a molecular monolayer (e.g. alkanethiols) or an atomic layer deposited conformal oxide. While such core-shell architectures are frequently effective in reducing surface defects, the surface passivation is invariably accompanied by a deterioration in optoelectronic properties due to the difficulty experienced by charge carriers in tunneling through the thin shell layer. The resulting trade-off between surface passivation and carrier extraction limits performance improvements in light harvesting devices. Thus there is a strong need for passivating layers that do not negatively impact carrier extraction.Herein, we show that graphitic carbon nitride coatings are highly effective in passivating the surfaces of inorganic nanowires and quantum dots while preserving excellent carrier transport and extraction. Three illustrative examples are provided together with in-depth spectroscopic and electrical characterization:(1) Cesium lead bromide (CsPbBr3) quantum dots passivated by g-C3N4 nanosheets and performing spectacularly as CO2 photoreduction catalysts and water-splitting photoanodes(2) The double helical ternary semiconductor SnIP passivated by g-C3N4 nanosheets which experienced a remarkable improvement in photoelectrochemical performance(3) Cadmium sulfide (CdS) nanowires passivated by C3N5 nanosheets resulting in a superior photocatalytic performance