Lamination of >21% Efficient Perovskite Solar Cells with Independent Process Control of Transport Layers and Interfaces.

Transport layer and interface optimization is critical for improving the performance and stability of perovskite solar cells (PSCs) but is restricted by the conventional fabrication approach of sequential layer deposition. While the bottom transport layer is processed with minimum constraints, the narrow thermal and chemical stability window of the halide perovskite (HP) layer severely restricts the choice of top transport layer and its processing conditions. To overcome these limitations, we demonstrate lamination of HPs─where two transport layer-perovskite half-stacks are independently processed and diffusion-bonded at the HP-HP interface─as an alternative fabrication strategy that enables self-encapsulated solar cells.

Visible-Light-Driven Photocatalysts for Self-Cleaning Transparent Surfaces.

Highly transparent photocatalytic self-cleaning surfaces capable of harvesting near-visible (365-430 nm) photons were synthesized and characterized. This helps to address a current research gap in self-cleaning surfaces, in which photocatalytic coatings that exhibit activity at wavelengths longer than ultraviolet (UV) generally have poor optical transparency, because of broadband scattering and the attenuation of visible light. In this work, the wavelength-dependent photocatalytic activity of Pt-modified TiO (Pt-TiO) particles was characterized, which exhibited activity for wavelengths up to 430 nm.

Durable Liquid- and Solid-Repellent Elastomeric Coatings Infused with Partially Crosslinked Lubricants.

Surfaces that are resistant to both liquid fouling and solid fouling are critical for many industrial and biomedical applications. However, surfaces developed to address these challenges thus far have been generally susceptible to mechanical damage. Herein, we report the design and fabrication of robust solid- and liquid-repellent elastomeric coatings that incorporate partially crosslinked lubricating chains within a durable polymer matrix.

Geometric Optimization of Bismuth Vanadate Core-Shell Nanowire Photoanodes using Atomic Layer Deposition.

In this study, systematic geometric tuning of core-shell nanowire (NW) architectures is used to decouple the contributions from light absorption, charge separation, and charge transfer kinetics in photoelectrochemical water oxidation. Core-shell-shell NW arrays were fabricated using a combination of hydrothermal synthesis of ZnO and atomic layer deposition (ALD) of SnO and BiVO. The length and spacing of the NW scaffold, as well as the BiVO film thickness, were systematically tuned to optimize the photoelectrochemical performance.

Enhanced Interfacial Toughness of Thermoplastic-Epoxy Interfaces Using ALD Surface Treatments.

Interfacial fracture and delamination of polymer interfaces can play a critical role in a wide range of applications, including fiber-reinforced composites, flexible electronics, and encapsulation layers for photovoltaics. However, owing to the low surface energy of many thermoplastics, adhesion to dissimilar material surfaces remains a critical challenge. In this work, we demonstrate that surface treatments using atomic layer deposition (ALD) on poly(methyl methacrylate) (PMMA) and fluorinated ethylene propylene (FEP) lead to significant increases in surface energy, without affecting the bulk mechanical response of the thermoplastic.

Mapping Viscoelastic and Plastic Properties of Polymers and Polymer-Nanotube Composites using Instrumented Indentation.

An instrumented indentation method is developed for generating maps of time-dependent viscoelastic and time-independent plastic properties of polymeric materials. The method is based on a pyramidal indentation model consisting of two quadratic viscoelastic Kelvin-like elements and a quadratic plastic element in series. Closed-form solutions for indentation displacement under constant load and constant loading-rate are developed and used to determine and validate material properties.