M. S. M. Saifullah and Hemant Raut of A*STAR’s Institute of Materials Research and Engineering in Singapore and their co-workers have developed a coating that matches the optical properties of the best conventional anti-reflective coatings (ARCs), while being more robust and easier to produce1.
Minuscule bumps that mimic the surface of a moth’s eye maximize the amount of light transmitted through a glass sheet.
ARCs are used in a variety of applications to reduce glare and increase the proportion of light transmitted through the glass or plastic beneath — potentially boosting the output of a solar module, for example.
Roughly 8% of light is reflected as it travels from air into glass, due to the difference in the refractive index between the materials. ARCs have refractive indices that gradually change from lower to higher values, offering a smooth transition for light that minimizes reflection. The moth’s eye achieves this with a layer of tiny bumps of 250 nanometers in height, but previous polymer films that mimic this pattern lacked sufficient durability for outdoor applications.
The coating developed by Saifullah, Raut and their team is based on polyhedral oligomeric silsesquioxane (POSS) — a molecular cage built from silicon and oxygen atoms. The team combined a modified form of POSS with three different molecules that can form strong links between them, and then spun the mixture onto glass to ensure an even distribution.
Using a process called nanoimprint lithography, the scientists pressed a non-stick nickel mold onto the mixture and heated it to 130 ºC, triggering a chemical reaction that cross-linked the reagents to form a polymer film. They repeated the process to create a second film on the other side of the glass.
After testing different proportions of the ingredients, the researchers produced coated glass that transmitted 98.2% of the light shone on it, matching the highest values reported for such structures. The film improved the transmittance of light falling at a wide range of angles by gradually bending incoming light rays toward the glass.
The coating showed no degradation after 100 hours in water at 85 ºC and could withstand sulfuric acid as well as a fog of salty water. It was also more scratch-resistant than conventional polymer-based ARCs. “These properties are highly desirable in a robust ARC that is targeted for outdoor commercial applications,” says Saifullah.
“The biggest challenge is the scalability of the POSS-based ARCs for use on large-area glass substrates,” he adds. “Roll-to-roll nanoimprint lithography is the way to do it. However, factors such as throughput have to be considered before commercialization can be realized.”The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering
Mat4Rail: EU Research Project on the Railway of the Future
23.02.2018 | Universität Bremen
Atomic structure of ultrasound material not what anyone expected
21.02.2018 | North Carolina State University
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy