Highly engineered mesoporous structures for optical processing

Parker, Geoffrey; Charlton, Martin D. B.; Zoorob, M.E.; Baumberg, Jeremy J.; Netti, M.C.; Lee, T

doi:10.1098/rsta.2005.1693

Cited by 18 publications

(6 citation statements)

References 9 publications

(7 reference statements)

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“…The double photonic crystal arrangement of the diatom structure makes its assembly a challenging task. Precise porous hexagonal arrays, resembling the single diatom layer, have been fabricated using the photochemical etching technique [70], but bonding of the two layers is necessary to complete the diatom structure. A fabrication process is explained in [71] for a square lattice, although the authors recognize the challenge it represents.…”

Section: Discussionmentioning

confidence: 99%

Light absorption enhancement and radiation hardening for triple junction solar cell through bioinspired nanostructures

et al. 2021

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Multi-junction solar cells constitute the main source of power for space applications. However, exposure of solar cells to the space radiation environment significantly degrades their performance across the mission lifetime. Here, we seek to improve the radiation hardness of the triple junction solar cell, GaInP/Ga(In)As/Ge, by decreasing the thickness of the more sensitive middle junction. Thin junctions facilitate the collection of minority carriers and show slower degradation due to defects. However, thinning the junction decreases the absorption, and consequently, the expected photocurrent. To compensate for this loss, we examined two bioinspired surface patterns that exhibit anti-reflective and light-trapping properties: (a) the moth-eye structure which enables vision in poorly illuminated environments and (b) the patterns of the hard cell of a unicellular photosynthetic micro-alga, the diatoms. We parametrize and optimize the biomimetic structures, aiming to maximize the absorbed light by the solar cell while achieving significant reduction in the middle junction thickness. The density of the radiation-induced defects is independent of the junction thickness, as we demonstrate using Monte Carlo simulations, allowing the direct comparison of different combinations of middle junction thicknesses and light trapping structures. We incorporate the radiation effects into the solar cell model as a decrease in minority carrier lifetime and an increase in surface recombination velocity, and we quantify the gain in efficiency for different combinations of junction thickness and the light-trapping structure at equal radiation damage. Solar cells with thin junctions compensated by the light-trapping structures offer a promising approach to improve solar cell radiation hardness and robustness, with up to 2% higher end-of-life efficiency than the commonly used configuration at high radiation exposure.

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Section: Discussionmentioning

confidence: 99%

Light absorption enhancement and radiation hardening for triple junction solar cell through bioinspired nanostructures

et al. 2021

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“…This indicates that the side walls of the diamond trenches are the {111} planes and they behave like etching stop planes. The anisotropy as mentioned above was extremely similar to that of Si etching by the KOH process 40 , 41 , which is frequently employed to fabricate Si trench structures for power devices. In reality, in terms of morphology, the diamond surface well-resembling the Si surface etched by the KOH process 40 , 41 was obtained through the proposed diamond etching process (Fig.…”

Section: Discussionmentioning

confidence: 64%

Anisotropic diamond etching through thermochemical reaction between Ni and diamond in high-temperature water vapour

Nagai

Nakanishi

Takahashi

et al. 2018

Sci Rep

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Diamond possesses excellent physical and electronic properties, and thus various applications that use diamond are under development. Additionally, the control of diamond geometry by etching technique is essential for such applications. However, conventional wet processes used for etching other materials are ineffective for diamond. Moreover, plasma processes currently employed for diamond etching are not selective, and plasma-induced damage to diamond deteriorates the device-performances. Here, we report a non-plasma etching process for single crystal diamond using thermochemical reaction between Ni and diamond in high-temperature water vapour. Diamond under Ni films was selectively etched, with no etching at other locations. A diamond-etching rate of approximately 8.7 μm/min (1000 °C) was successfully achieved. To the best of our knowledge, this rate is considerably greater than those reported so far for other diamond-etching processes, including plasma processes. The anisotropy observed for this diamond etching was considerably similar to that observed for Si etching using KOH.

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“…Although pigments and dyes are generally used as coloring tools in the industry, they fade over time and often require additional treatment to ensure that the color is sustained. The field of biomimetics is the force behind the development of photonic crystal (PC) structures, which are structurally diverse in nature. − The colors that PC structures provide are bright, adaptive camouflage, and low-reflectance. Moreover, they are iridescent and cannot be mimicked by chemical dyes or pigments.…”

Section: Introductionmentioning

confidence: 99%

Flexible Photonic Crystal Material for Multiple Anticounterfeiting Applications

Peng

Hsu

et al. 2018

ACS Appl. Mater. Interfaces

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In this study, a nanoimprinting method was introduced to fabricate polycarbonate films with transparent and flexible photonic crystal (FPC) structures. The fabricated flexible polymer films display a full-color grating because of the nanohemispherical structures on the surface. Through the Bragg diffraction formula, it was confirmed that the FPC polymer films transfer a part of the light energy to the second-order diffraction spectrum. Furthermore, the full-color grating properties can be modulated through geometric deformation because of the film’s elasticity. Additionally, anticounterfeiting features were also successfully achieved when the polymer films were either engraved with drawings and bent or patterned with fluorophores, which can be revealed under ultraviolet light. The most important aspect of this research is that the preparation of this FPC-structured polymer film is inexpensive and convenient, enabling the mass production of a new generation of smart materials.

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Highly engineered mesoporous structures for optical processing

Cited by 18 publications

References 9 publications

Light absorption enhancement and radiation hardening for triple junction solar cell through bioinspired nanostructures

Light absorption enhancement and radiation hardening for triple junction solar cell through bioinspired nanostructures

Anisotropic diamond etching through thermochemical reaction between Ni and diamond in high-temperature water vapour

Flexible Photonic Crystal Material for Multiple Anticounterfeiting Applications

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