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[[Vol. 50]High-Performance Solar Cells Based on Silicon Nanopencil Structures_ WPI-MANA.pdf](https://mdr.nims.go.jp/filesets/76dd9c5d-88ad-4d09-a4af-03b03ec88317/download)

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International Center for Materials Nanoarchitectonics (WPI-MANA)

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[[Research Highlights Vol.50] High-Performance Solar Cells Based on Silicon Nanopencil Structures](https://mdr.nims.go.jp/datasets/c599fdb3-a4ed-41e0-bbe4-255deedbf491)

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2022/03/31 16:27 High-Performance Solar Cells Based on Silicon Nanopencil Structures| MANAhttps://www.nims.go.jp/mana/research/highlights/vol50.html 1/2Previous  Index  NextResearch Highlights[Vol. 50]High-Performance Solar Cells Based on Silicon Nanopencil Structures16 Jul, 2019Figure: Nanowire array structures are called moss eye structures, which become black colordue to the suppression of the light reflectance. Solar light energy create electrons and holesin nanowire structures and these electrons and holes are effectively separated by pnjunction, resulting in high performance PV cells.Solar cells are an important alternative energy source. The traditional solar-cell material of choiceis crystalline silicon, which enables high power conversion efficiency, is stable, and has a well-established manufacturing process. Drawbacks with crystalline silicon are the high production costand its fundamental efficiency limit. Now, Naoki Fukata at the International Center for MaterialsNanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan, and colleagues havefabricated a high-efficiency solar-cell material also based on silicon but with a significantly lowerproduction cost. This work was done in collaboration with Oji Holdings Corporation.The material consists of nano-sized pencil-shaped silicon rods — silicon nanopencils (SiNPs) — allaligned in one direction, etched out on a silicon wafer. The researchers used a combination ofcolloidal lithography and plasma reactive ion etching techniques. In colloidal lithography, a patternis synthesized on a material by putting an ordered arrangement of colloidal particles on it;subsequent irradiation and removal of excess colloidal material then results in the patternedstructure. In plasma reactive ion etching, material is etched away by using a chemically reactiveplasma.https://www.nims.go.jp/mana/research/highlights/vol49.htmlhttps://www.nims.go.jp/mana/research/highlights/index.htmlhttps://www.nims.go.jp/mana/research/highlights/vol51.html2022/03/31 16:27 High-Performance Solar Cells Based on Silicon Nanopencil Structures| MANAhttps://www.nims.go.jp/mana/research/highlights/vol50.html 2/2The obtained SiNP arrays where then made into proper solar cells with channels of silver betweenareas of SiNPs. When studying the conversion efficiency of their devices, Fukata and colleaguesnoted that the plasma etching process led to the development of too many defects, loweringdevice performance. To overcome this issue, the scientists applied a chemical polish etchingmethod, which leads to a smooth device surface and better performance characteristics.The researchers experimented with different structural parameters. In particular, they looked atthe influence of the distance (pitch) between individual SiNPs, and so the density of SiNPs on thesubstrate. By also considering different silicon wafer thicknesses, they were able to obtain amaximum power conversion efficiency of 14.3%.Further structural optimization of SiNP-based solar cells could lead to even better performancecharacteristics of devices of the type investigated by Fukata and colleagues. Quoting the scientists:“This high-performance device holds considerable potential for solar cell production on an industrialscale.”Reference“Fabrication of high-performance ordered radial junction silicon nanopencil T solar cells by fine-tuning surface carrier recombination and structure morphology”Junyi Chen, Thiyagu Subramani, Wipakorn Jevasuwan, Kotaro Dai, Kei Shinotsuka, YoshihisaHatta, Naoki FukataJournal : Nano Energy 56, 604 (2019).DOI : 10.1016/j.nanoen.2018.12.002AffiliationsInternational Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for MaterialsScience (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, JapanContact informationInternational Center for Materials Nanoarchitectonics(WPI-MANA)National Institute for Materials Science1-1 Namiki, Tsukuba, Ibaraki 305-0044 JapanPhone: +81-29-860-4710E-mail: mana-pr[AT]ml.nims.go.jphttps://samurai.nims.go.jp/profiles/jevasuwan_wipakorn?locale=enhttps://samurai.nims.go.jp/profiles/fukata_naoki?locale=enhttps://www.sciencedirect.com/science/article/abs/pii/S2211285518309066?via%3Dihub