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Review of the Fundamental Principles and Performances on Lminescent Solar Concentrators
Kukhyun Jo,Hyo Jung Kim 한국진공학회(ASCT) 2021 Applied Science and Convergence Technology Vol.30 No.1
First proposed by Willes H. Weber in 1976, the basic concept of a luminescent solar concentrator (LSC) is to collect emitted light via total internal reflection using a light-emitting material that also absorbs light. Therefore, LSCs do not require the assistance of expensive devices such as sun-tracking systems or heat sinks to concentrate solar light. Since its inception, the LSC has attracted attention from researchers in photovoltaic technology. Most research on LSCs can be classified into three categories: luminescent materials, the waveguide matrix, and applications of LSCs. In this review, we review briefly fundamental principles and performance developments involving LSCs.
Optical Properties of EVA Films Including V570 for Transparent Luminescent Solar Concentrator
Kukhyun Jo,Seungyeon Hong,Hyo Jung Kim 한국진공학회(ASCT) 2020 Applied Science and Convergence Technology Vol.29 No.1
We fabricated a transparent luminescent solar concentrator (LSC) film using Lumogen F Violet 570 (V570) luminescent molecules and polyethylene-co-vinylaccetate (EVA) polymer. The transparent LSC was produced by a solution process (Doctor Blade coating) using a tetrahydrofuran solvent. We measured physical properties such as thickness, absorption efficiency, emission efficiency, and photocurrent characteristics of the LSC films. We also discuss the physical properties of the LSC films by observing the crystallinity and surface morphology using X-ray diffraction and atomic force microscopy. During the formation of LSC films, V570 molecules did not induce macroscopic changes, but had a significant effect on nanoscale morphology, i.e., surface roughness. In addition, changes in the light scattering characteristics were observed when the V570 concentration increased, which was found by X-ray diffraction to be related to the formation of V570 crystals, not EVA crystals. The light scattering and surface roughness of a film could be improved through heat treatment. As a result, we obtained ~ 1.3 times larger photocurrent in thermally treated LSC films.
Nanowall formation by maskless wet-etching on a femtosecond laser irradiated silicon surface
Lee, Siwoo,Jo, Kukhyun,Keum, Hee-sung,Chae, Sangmin,Kim, Yonghyeon,Choi, Jiyeon,Lee, Hyun Hwi,Kim, Hyo Jung Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.437 No.-
<P><B>Abstract</B></P> <P>We found that micro-cells surrounded by nanowalls can be formed by a maskless wet-etching process on Si (100) surfaces possessing Laser Induced Periodic Surface Structure (LIPSS) by femtosecond laser irradiation. The LIPSS process could produce periodic one-dimensional micron scale ripples on a Si surface, which could be developed into micro-cells by a subsequent etching process. The solution etching conditions strongly affected both the micro-cell and nanowall shapes such as the height and the thickness of nanowalls. The tetramethylammonium hydroxide solution created thin nanowalls and the resulting micro-cells with a well-flattened bottom while the KOH solution formed thick walls and incomplete micro-cells. The bottoms of micro-cells surrounded by the nanowalls were considerably flat with a 3.10 nm surface roughness. A pentacene layer was deposited on the micro-cells of a Si surface to evaluate the film properties by grazing incidence wide angle x-ray scattering measurements. The pentacene film on the micro-cell Si surface showed a strong film phase, which was comparable to the film phase grown on the atomically flat Si surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High aspect ratio nanowalls with micro-cells were fabricated by laser assisted wet-etching process. </LI> <LI> The surface roughness of micro-cells was 3.10 nm on average. </LI> <LI> Nanowalls improved the lateral growth of thin film phase penetacene layer by size confining effect. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>