The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

50 Years of Image Analysis

A mean-field phase diagram for conformationally symmetric diblock melts using the standard Gaussian polymer model is presented. Our calculation, which traverses the weak- to strong-segregation regimes, is free of traditional approximations. Regions of stability are determined for disordered (DIS) melts and for ordered structures including lamellae (L), hexagonally packed cylinders (H), body-centered cubic spheres (QIm3m), close-packed spheres (CPS), and the bicontinuous cubic network with Ia3d symmetry (QIa3d). The CPS phase exists in narrow regions along the order−disorder transition for χN ≥ 17.67. Results suggest that the QIa3d phase is not stable above χN ∼ 60. Along the L/QIa3d phase boundaries, a hexagonally perforated lamellar (HPL) phase is found to be nearly stable. Our results for the bicontinuous Pn3m cubic (QPn3m) phase, known as the OBDD, indicate that it is an unstable structure in diblock melts. Earlier approximation schemes used to examine mean-field behavior are reviewed, and compa...

Unifying Weak- and Strong-Segregation Block Copolymer Theories

Perovskite solar cells (PSCs) have attracted much attention because of their rapid rise to 22% efficiencies. Here, we review the rapid evolution of PSCs as they enter a new phase that could revolutionize the photovoltaic industry. In particular, we describe the properties that make perovskites so remarkable, and the current understanding of the PSC device physics, including the operation of state-of-the-art solar cells with efficiencies above 20%. The extraordinary progress of long-term stability is discussed and we provide an outlook on what the future of PSCs might soon bring the photovoltaic community. Some challenges remain in terms of reducing non-radiative recombination and increasing conductivity of the different device layers, and these will be discussed in depth in this review.

The rapid evolution of highly efficient perovskite solar cells

A Review of Perovskites Solar Cell Stability

The colours of insects serve important visual functions in aiding mate recognition, camouflage and warning. The display of insects is usually static, as cuticle coloration does not (or hardly) change during the lifespan of a mature imago form. Here, we describe a case of humidity-dependent, brilliant coloration in the green forester moth, Adscita statices. We show, by employing spectroscopic and ultrastructural methods, that the moth's colour results from the interference of incident light with an unusual hydrophilic melanized-chitin multilayer present in the wing scales. Humidity changes in the environment affect the multilayer properties, causing a significant shift of the green-peaking reflectance in the dry state to a rusty colour when damp, resulting in the strong colour change between day and dusk or dawn.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsbl.2019.0516

Humidity-dependent colour change in the green forester moth, Adscita statices.

A range of plants developed leaves, the surfaces of which prevent or diminish insect adhesion due to their microscopic topography. Well known examples include the leaves of the lychee tree (Litchi chinensis). Here, we report a method to coat substrates with ethyl cellulose microparticles that exhibit wrinkled surfaces, resulting in surface morphologies that closely resemble those of insect repelling plants, i.e., Litchi chinensis. The microparticles were prepared by electrospraying, a method that allowed tuning of the particle size and surface morphology. By measuring the traction forces of Colorado potato beetles walking on these surfaces, the wrinkly microsphere parameters were optimized, resulting in biomimetic surfaces that surpass the antiadhesive properties of the biological role model. This study may pave the way to sustainable, nontoxic insecticide replacements.

Insect Antiadhesive Surfaces Using Electrosprayed Wrinkled Ethyl Cellulose Particles.

Living Light is a biennial conference focused on all aspects of light–matter interaction in biological organisms with a broad, interdisciplinary outlook. The 2018 edition was held at the Moller Centre in Cambridge, UK, from April 11th to April 14th, 2018. Living Light’s main goal is to bring together researchers from different backgrounds (e.g., biologists, physicists and engineers) in order to discuss the current state of the field and sparkle new collaborations and new interdisciplinary projects. With over 90 national and international attendees, the 2018 edition of the conference was strongly multidisciplinary: oral and poster presentations encompassed a wide range of topics ranging from the evolution and development of structural colors in living organisms and their genetic manipulation to the study of fossil photonic structures.

https://www.mdpi.com/2313-7673/3/2/11/pdf

Living Light 2018: Conference Report.

Solar Thermal Energy: Polydopamine Nanoparticle Doped Nanofluid for Solar Thermal Energy Collector Efficiency Increase (Adv. Sustainable Syst. 1/2020)

This year, 2017, marks the centenary of the first publication of 'On Growth and Form', by the extraordinary Scottish classicist, biologist and part-time mathematician, D'Arcy Wentworth Thompson [1]...

https://royalsocietypublishing.org/doi/pdf/10.1098/rsfs.2017.0035

Bodo D. Wilts

Papers

Humidity-dependent colour change in the green forester moth, Adscita statices.

Insect Antiadhesive Surfaces Using Electrosprayed Wrinkled Ethyl Cellulose Particles.

Living Light 2018: Conference Report.

Solar Thermal Energy: Polydopamine Nanoparticle Doped Nanofluid for Solar Thermal Energy Collector Efficiency Increase (Adv. Sustainable Syst. 1/2020)

Emergence and function of complex form in self-assembly and biological cells