- Award ID(s):
- 1922321
- PAR ID:
- 10464920
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 120
- Issue:
- 34
- ISSN:
- 0027-8424
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract Durable hydrophobic materials have attracted considerable interest in the last century. Currently, the most popular strategy to achieve hydrophobic coating durability is through the combination of a perfluoro-compound with a mechanically robust matrix to form a composite for coating protection. The matrix structure is typically large (thicker than 10 μm), difficult to scale to arbitrary materials, and incompatible with applications requiring nanoscale thickness such as heat transfer, water harvesting, and desalination. Here, we demonstrate durable hydrophobicity and superhydrophobicity with nanoscale-thick, perfluorinated compound-free polydimethylsiloxane vitrimers that are self-healing due to the exchange of network strands. The polydimethylsiloxane vitrimer thin film maintains excellent hydrophobicity and optical transparency after scratching, cutting, and indenting. We show that the polydimethylsiloxane vitrimer thin film can be deposited through scalable dip-coating on a variety of substrates. In contrast to previous work achieving thick durable hydrophobic coatings by passively stacking protective structures, this work presents a pathway to achieving ultra-thin (thinner than 100 nm) durable hydrophobic films.more » « less
-
Abstract Liquid‐infused silicones are a promising solution for common surface adhesion problems, such as ice accumulation and biofilm formation, yet they generally lack the tunability, mechanical durability and/or longevity essential for industrial applications. Self‐stratifying porous silicones (SPS) infused with compatible silicone oil are developed as a passive strategy to address these shortcomings. Through emulsion templating, porosity is formed in the bulk polymer, providing increased free volume for oil infusion, while a non‐porous skin layer is formed at the surface. The bulk porosity and pore size distribution of SPS are independently controlled by varying water and surfactant concentration respectively, leading to a higher volume of oil infusion and improved oil retention relative to an unmodified silicone. Despite a higher oil loading and bulk porosity, the skin layer provides liquid‐infused SPS with a comparable surface elasticity to liquid‐infused silicones. The potential of liquid‐infused SPS as a nontoxic fouling release coating for marine applications is demonstrated using laboratory assays against a variety of soft and hard fouling organisms.
-
Abstract Graphene, a single layer conductor, can be combined with other functional materials for building efficient optoelectronic devices. However, transferring large‐area graphene onto another material often involves dipping the material into water and other solvents. This process is incompatible with water‐sensitive materials such as organometal halide perovskites. Here, a dry method is used and succeeded, for the first time, in stacking centimeter‐sized graphene directly onto methylammonium lead iodide thin films without exposing the perovskite film to any liquid. Photoemission spectroscopy and nanosecond time‐resolved photoelectrical measurement show that the graphene/perovskite interface does not contain significant amount of contaminants and sustain efficient interfacial electron transfer. The use of this method in fabricating graphene‐on‐perovskite photodetectors is further demonstrated. Besides a better photoresponsivity compared to detectors fabricated by the conventional perovskite‐on‐graphene structure, this dry transfer method provides a scalable pathway to incorporate graphene in multilayer devices based on water‐sensitive materials.
-
Despite the high-efficiency and low-cost prospect for perovskite solar cells, great concerns of lead toxicity and instability remain for this technology. Here, we report an encapsulation strategy for perovskite modules based on lead-adsorbing ionogel, which prevents lead leakage and withstand long-term stability tests. The ionogel layers integrated on both sides of modules enhance impact resistance. The self-healable ionogel can prevent water permeation into the perovskite layer and adsorb lead that might leak. The encapsulated devices pass the damp heat and thermal cycling accelerated stability tests according to International Electrotechnical Commission 61215 standard. The ionogel encapsulation reduces lead leakage to undetectable level after the hail-damaged module is soaked in water for 24 hours. Even being rolled over by a car followed by water soaking for 45 days, the ionogel encapsulation reduces lead leakage by three orders of magnitude. This work provides a strategy to simultaneously address lead leakage and stability for perovskite modules.more » « less
-
Mechanoluminescent (ML) materials are used for fabricating sensors and other devices such as artificial skin, colorful displays, and energy harvesting devices. However, a key challenge in developing ML-based sensors is the ability to effectively capture and efficiently transmit ML light from the sensing location. Here we report a flexible and sensitive thin film pressure sensor, created using a novel combination of ML material and perovskite. In this work, we adopted a simple lateral type design of a thin pressure sensor primarily consisting of (i) a sensing layer of copper-doped zinc sulfide (ZnS:Cu)/polydimethylsiloxane (PDMS) composite and (ii) a light absorbing layer of perovskite. The mixed halide perovskite, a light absorbing material, fully absorbs the green light emitted from ZnS:Cu. The sensor demonstrated consistent signal output under the mechanical bending test. A thin encapsulation layer of PMMA on the perovskite layer prevents moisture inclusion. This innovative technique of utilizing integrated thin perovskite to efficiently harvest ML light has the potential to open up new avenues for advanced research in ML-perovskite-based sensor systems.more » « less