Nanocavity-assisted single-crystalline Ti3+ self-doped blue TiO2(B) as efficient cocatalyst for high selective CO2 photoreduction of g-C3N4

Two-dimensional (2D) graphitic carbon nitride (g-C₃N₄) has invoked significant interest for photocatalytic applications for its excellent features such as high surface area, visible light absorption, and easy transportation of photogenerated charge carriers, but the most reported g-C₃N₄ show relatively low photoactivity due to inferior conductivity and rapid recombination of carriers. These can be overcome by inducing porosity in g-C₃N₄, followed by exfoliation and combining with other materials. Herein, we synthesize nanocavity-assisted oxygen-deficient Ti³⁺ self-doped blue TiO₂(B) nanorods (BT) and integrate them on exfoliated porous g-C₃N₄ (PCN). The synthesized materials are tested for photocatalytic conversion of CO₂ into solar fuels (H₂, CO, and CH₄). The fabricated BT/PCN heterostructures exhibit higher photocatalytic CO₂ conversion activity and 92% CO-evolving selectivity than BT and PCN. The enhancement in activity of BT/PCN can be attributed to the efficient separation and transportation of charge carriers, facilitated by the unique properties of BT, PCN, and their synergistic interactions. We believe that these results can contribute to the improvement of cost-effectiveness, feasibility, and overall performance for real photocatalytic systems.     

On Helicoidal Surfaces in a Conformally Flat 3-Space

In this paper, we discuss the problem of finding explicit parametrizations for the helicoidal surfaces in a conformally flat 3-space \(\mathbb {E}^3_F\) with prescribed extrinsic curvature or mean curvature given by smooth functions. Also, we give examples for helicoidal surfaces with some extrinsic curvature and mean curvature functions in \(\mathbb {E}^3_F\).     

Large area,waterproof, air stable and cost effective efficient perovskite solar cells through modified carbon hole extraction layer

The conventional unstable and expensive hole transporting materials (HTM) has been replaced by cost effective modified carbon hole extraction layer. Herein, we demonstrated a new recipe toward air stable and waterproof modified carbon hole extraction layer for efficient perovskite solar cells (PSCs). The commercial available carbon ink modified with methylammonium lead iodide (MAI) has been used as hole extraction layer for ambipolar perovskite solar cells. The fabricated optimized perovskite solar cell having Glass/FTO/mp-TiO₂/MAPbI_3-xCl_x/carbon + MAI/Carbon configuration exhibited η = 13.87% power conversion efficiency (PCE) with open circuit voltage (V_OC) 0.997 V, current density (J_SC) = 21.41 mAcm^?2 and fill factor (FF) 0.65. Furthermore, the air stability were tested at room temperature in open atmosphere. The water proof stability was tested under water flushing. Our results revealed that, although our carbon based devices show lower PCE (η = 13.87%) compared to spiro-MeOTAD HTM (η = 15%), the fabricated PSCs could even retain >90% after water exposure >20 times and ambient air stability more than 160 days. Further the large area device (>1 cm²) device shows 13.04% PCE with Jsc = 21.47 mAcm^?2, V_OC = 0.996 V and FF = 0.61. We have also demonstrated >13% efficiency for large area device (>1.1 cm²), demonstrating that the developed method is simple, cost effective and promising towards large area device fabrication. The developed methodology based on low cost carbon hole extraction layer will be helpful towards waterproof and air stable perovskite solar cells for large-area devices.     

Influence of Material Properties on the Damage-Reporting and Self-Healing Performance of a Mechanically Active Dynamic Network Polymer in Coating Applications

We conducted a detailed investigation of the influence of the material properties of dynamic polymer network coatings on their self-healing and damage-reporting performance. A series of reversible polyacrylate urethane networks containing the damage-reporting diarylbibenzofuranone unit were synthesized, and their material properties (e.g., indentation modulus, hardness modulus, and glass-transition temperature) were measured conducting nanoindentation and differential scanning calorimetry experiments. The damage-reporting and self-healing performances of the dynamic polymer network coatings exhibited opposite tendencies with respect to the material properties of the polymer network coatings. Soft polymer network coatings with low glass-transition temperature (~10 °C) and indentation hardness (20 MPa) exhibited better self-healing performance (almost 100%) but two times worse damage-reporting properties than hard polymer network coatings with high glass-transition temperature (35~50 °C) and indentation hardness (150~200 MPa). These features of the dynamic polymer network coatings are unique; they are not observed in elastomers, films, and hydrogels, whereby the polymer networks are bound to the substrate surface. Evidence indicates that controlling the polymer’s physical properties is a key factor in designing high-performance self-healing and damage-reporting polymer coatings based on mechanophores.     

Unusual Transformation from a Solvent‐Stabilized 1D Coordination Polymer to a Metal–Organic Framework (MOF)‐Like Cross‐Linked 3D Coordination Polymer

An unusual 1D‐to‐3D transformation of a coordination polymer based on organic linkers containing highly polar push–pull π‐conjugated side chains is reported. The coordination polymers are synthesized from zinc nitrate and an organic linker, namely, 2,5‐bis{4‐[1‐(4‐nitrophenyl)pyrrolidin‐2‐yl]butoxy}terephthalic acid, which possesses highly polar (4‐nitrophenyl)pyrrolidine groups, with high dipole moments of about 7 D. The coordination polymers exhibit an unusual transformation from a soluble, solvent‐stabilized 1D coordination polymer into an insoluble, metal–organic framework (MOF)‐like 3D coordination polymer. The coordination polymer exhibits good film‐forming ability, and the MOF‐like films are insoluble in conventional organic solvents.     

Investigation on newly designed low resistivity polyimide-type alignment layer for reducing DC image sticking of in-plane switching liquid crystal display

Soluble polyimide-type alignment layer is widely used in in-plane switching (IPS) liquid crystal display (LCD) because of its excellent reliability owing to high imidisation ratio during long-term driving, high voltage-holding ratio and low ion density. Nevertheless, it exhibits slow direct current (DC) discharging property due to its high resistivity, causing significant DC image-sticking problem. In this study, we doped inorganic salt to control the resistivity of soluble polyimide-type alignment layer and found that this approach reduced DC image sticking greatly without any loss of reliability property in IPS-LCD.     

Suppressing pretilt angle for enhancing black quality in diagonal viewing angle of homogenously aligned liquid crystal display

The diagonal viewing angle light leakage in a black state of in-plane switching (IPS) liquid crystal display (LCD) associated with pretilt angle has been investigated. The mechanical rubbing process with a cloth causes relatively high pretilt angle in the homogenously aligned liquid crystals (LCs) so that the tilted LC director results in increase of a light leakage in a black state at diagonal viewing angles. In this study, we theoretically estimated using classical optic theory how the light leakage in a black state at diagonal viewing angle is associated with the pretilt angle and also proposed an effective method to reduce the pretilt angle from 1.5° to 0° in rubbed IPS LCD by utilising polymer stabilisation. With this approach, we could successfully acquire a better black quality in all viewing angles as compared with normal IPS LCD.     

Aminopyridine-containing supramolecular polydiacetylene: film formation,thermochromism and micropatterning

Polydiacetylenes (PDAs) are intrinsically supramolecular conjugated polymers that are prepared by polymerisation of self-assembled diacetylene (DA) supramolecules. Owing to their highly aggregating nature and insolubility, fabrication of transparent and homogeneous films has been challenging. By taking advantage of multiple hydrogen bonding, a transparent and thin PDA film was readily prepared with an aminopyridine-containing DA monomer. The PDA film displayed an irreversible blue-to-red colour change between 30 and 90 °C and a reversible red-to-yellow thermochromism between 30 and 190 °C. Micropatterned colour and fluorescence PDA images were readily fabricated by employing a simple photolithographic approach.