On the Relationship between Corneal Biomechanics, Macrostructure, and Optical Properties

Optical properties of the cornea are responsible for correct vision; the ultrastructure allows optical transparency, and the biomechanical properties govern the shape, elasticity, or stiffness of the cornea, affecting ocular integrity and intraocular pressure. Therefore, the optical aberrations, corneal transparency, structure, and biomechanics play a fundamental role in the optical quality of human vision, ocular health, and refractive surgery outcomes. However, the inter-relationships of those properties are not yet reported at a macroscopic scale within the hierarchical structure of the cornea. This work explores the relationships between the biomechanics, structure, and optical properties (corneal aberrations and optical density) at a macro-structural level of the cornea through dual Placido–Scheimpflug imaging and air-puff tonometry systems in a healthy young adult population. Results showed correlation between optical transparency, corneal macrostructure, and biomechanics, whereas corneal aberrations and in particular spherical terms remained independent. A compensation mechanism for the spherical aberration is proposed through corneal shape and biomechanics.

The influence of the surface density of oriented nickel networks on the conducting electrode’s optical transparency

This study is part of the work on the creation of a transparent conductive coating based on oriented nanonetwork and submicron nickel fibres. It is devoted to finding the optimal values of electrical conductivity and optical transparency of the developed coating. In this work, we study the transmission spectra of oriented nickel networks on a glass substrate in the UV, visible and near-IR regions at different amounts of deposited metal. An exciting feature of the coating was discovered: in the range of 950 nm and above, there is a "bend" of the transmission spectrum downward. This bend (increased absorption of radiation in the near-IR region) is observed only in the presence of nickel nanonetwork and is not typical for a pure submicron network.

Transmission spectra of transparent electrodes based on oriented platinum nanowires at various concentrations of the metal used

The paper investigates the optical transparency dependence of a coating based on an oriented network of platinum nanowires on the amount of metal used. Oriented platinum nanowires on a glass surface are produced by chemical deposition from an aqueous hexachloroplatinic acid solution. The topography of the deposited metal layer on glass is visualized using atomic force microscopy. Optical transparency was investigated with a spectrophotometer. In almost the entire region of optical radiation, the transparency is approximately 98%. The absorption spectrum shows that the absorption coefficient increases sharply in the near UV region.

Review on Tailoring PEDOT:PSS Layer for Improved Device Stability of Perovskite Solar Cells

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has high optical transparency in the visible light range and low-temperature processing condition, making it one of the most widely used polymer hole transport materials inverted perovskite solar cells (PSCs), because of its high optical transparency in the visible light range and low-temperature processing condition. However, the stability of PSCs based on pristine PEDOT:PSS is far from satisfactory, which is ascribed to the acidic and hygroscopic nature of PEDOT:PSS, and property differences between PEDOT:PSS and perovskite materials, such as conductivity, work function and surface morphology. This review summaries recent efficient strategies to improve the stability of PEDOT:PSS in PSCs and discusses the underlying mechanisms. This review is expected to provide helpful insights for further increasing the stability of PSCs based on commercial PEDOT:PSS.

On the Relationship between Corneal Biomechanics, Macrostructure and Optical Properties

Optical properties of the cornea are responsible for correct vision, ultrastructure allows optical transparency and biomechanical properties governs the shape, elasticity or stiffness of the cor-nea affecting ocular integrity and intraocular pressure. Therefore, optical aberrations, corneal transparency, structure and biomechanics play a fundamental role in the optical quality of hu-man vision, ocular health and refractive surgery outcomes. However, the convergence of those properties is not yet reported at macroscopic scale within the hierarchical structure of the cornea. This work explores the relationships between biomechanics, structure and optical properties (corneal aberrations and optical density) at macrostructural level of the cornea through dual Placido-Scheimpflug imaging and air-puff tonometry systems in a healthy young adult popula-tion. Results showed convergence between optical transparency, corneal macrostructure and biomechanics.

Silver Nanowire Networks: Ways to Enhance Their Physical Properties and Stability

Silver nanowire (AgNW) networks have been intensively investigated in recent years. Thanks to their attractive physical properties in terms of optical transparency and electrical conductivity, as well as their mechanical performance, AgNW networks are promising transparent electrodes (TE) for several devices, such as solar cells, transparent heaters, touch screens or light-emitting devices. However, morphological instabilities, low adhesion to the substrate, surface roughness and ageing issues may limit their broader use and need to be tackled for a successful performance and long working lifetime. The aim of the present work is to highlight efficient strategies to optimize the physical properties of AgNW networks. In order to situate our work in relation to existing literature, we briefly reported recent studies which investigated physical properties of AgNW networks. First, we investigated the optimization of optical transparency and electrical conductivity by comparing two types of AgNWs with different morphologies, including PVP layer and AgNW dimensions. In addition, their response to thermal treatment was deeply investigated. Then, zinc oxide (ZnO) and tin oxide (SnO2) protective films deposited by Atmospheric Pressure Spatial Atomic Layer Deposition (AP-SALD) were compared for one type of AgNW. We clearly demonstrated that coating AgNW networks with these thin oxide layers is an efficient approach to enhance the morphological stability of AgNWs when subjected to thermal stress. Finally, we discussed the main future challenges linked with AgNW networks optimization processes.

Hydrophobicity in clearwing butterflies and moths: impact of scale 2 micro and nanostructure, and trade-off with optical transparency

In opaque butterflies and moths, scales ensure vital functions like camouflage, thermoregulation, and hydrophobicity. Wing transparency in some species - achieved via modified or absent scales - raises the question of whether hydrophobicity can be maintained and of it dependence on scale microstructural (scale presence, morphology, insertion angle, and coloration) and nanostructural (ridge spacing and width) features. To address these questions, we assessed hydrophobicity in 23 clearwing species differing in scale micro and nanofeatures by measuring static contact angle (CA) of water droplets in the opaque and transparent patches of the same individuals at different stages of evaporation. We related these measures to wing structures (macro, micro, and nano) and compared them to predictions from Cassie-Baxter and Wenzel models. We found that overall, transparency is costly for hydrophobicity and this cost depends on scale microstructural features: transparent patches are less hydrophobic and lose more hydrophobicity with water evaporation than opaque patches. This loss is attenuated for higher scale densities, coloured scales (for erect scales), and when combining two types of scales (piliform and lamellar). Nude membranes show lowest hydrophobicity. Best models are Cassie-Baxter models that include scale microstructures for erect scales, and scale micro and nanostructures for flat scales. All findings are consistent with the physics of hydrophobicity, especially on multiscale roughness. Finally, wing hydrophobicity negatively relates to optical transparency. Moreover, tropical species have more hydrophobic transparent patches but similarly hydrophobic opaque patches compared to temperate species. Overall, diverse microstructures are likely functional compromises between multiple requirements.