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159 results on '"Liao, Yongping"'

5. Topologically protected mobile solid $^3$He on carbon nanotube

Author

Todoshchenko, Igor, Kamada, Masahiro, Kaikkonen, Jukka-Pekka, Liao, Yongping, Savin, Alexander, Will, Marco, Sergeicheva, Elena, Abhilash, Thanniyil Sebastian, Kauppinen, Esko, and Hakonen, Pertti

Subjects
Condensed Matter - Other Condensed Matter, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Low dimensional fermionic quantum systems are exceptionally interesting because they reveal distinctive physical phenomena, including among others, topologically protected excitations, edge states, frustration, and fractionalization. Two-dimensional $^3$He has indeed shown a remarkable variety of phases including the unusual quantum spin liquid. Our aim was to lower the dimension of the $^3$He system even more by confining it on a suspended carbon nanotube. In our measurements the mechanical resonance of the nanotube with adsorbed sub-monolayer of $^3$He was measured as a function of coverage and temperature down to 10\;mK. At lowest temperatures and low coverages we have observed a liquid-gas coexistence which transforms to the famous 1/3 commensurate solid phase at intermediate densities. However, at larger monolayer densities we have observed a quantum phase transition from 1/3 solid to a completely new, soft and mobile solid phase. We interpret this mobile solid phase as a bosonic commensurate crystal consisting of helium dimers with topologically protected zero-point vacancies which are delocalized at low temperatures. We thus demonstrate that $^3$He on a nanotube merges both fermionic and bosonic phenomena, with a quantum phase transition between fermionic solid 1/3 phase and a newly observed bosonic dimer solid. The mobility and softness of the bosonic dimer solid are conditioned by topology-induced vacancies which become delocalized at low temperatures owing to a large zero-point motion., Comment: 36 pages, including 19 pages of the main text and 17 pages of the Methods section, 4 Figures, all in the main text

Published
2020

8. Gas-phase synthesis of carbon nanotube-graphene heterostructures

Author

Ahmad, Saeed, Jiang, Hua, Mustonen, Kimmo, Zhang, Qiang, Hussain, Aqeel, Khan, Abu Taher, Wei, Nan, Tavakkoli, Mohammad, Liao, Yongping, Ding, Er-Xiong, Kotakoski, Jani, and Kauppinen, Esko I.

Subjects
Physics - Applied Physics, Condensed Matter - Materials Science
Abstract

Graphene and carbon nanotubes (CNTs) share the same atomic structure of hexagonal carbon lattice. Yet, their synthesis differs in many aspects, including the shape and size of the catalyst. Here, we demonstrate a floating-catalyst chemical vapor deposition (FCCVD) technique for substrate-free, single-step growth of CNT-graphene heterostructures (CNT-G-H) using ethylene as a carbon source. The formation of CNT-G-H is directly evidenced by lattice-resolved (scanning) transmission electron microscopy (STEM) and electron diffraction experiments, corroborated by atomic force microscopy (AFM). Our experiments show the relative number density of graphene-nanoflakes can be tuned by optimizing the synthesis conditions. Since in the applied process the formation of the structures take place in gas-suspension, the as-synthesized CNT-G-H films can be deposited on any surface in ambient temperature with an arbitrary thickness. Moreover, this process of CNT-G-H synthesis with strong universality has also been realized in multiple systems of ethylene-based FCCVD with various catalysts and set-ups.

Published
2019

9. Enhanced Tunnelling in a Hybrid of Single-Walled Carbon Nanotubes and Graphene

Author

Liao, Yongping, Mustonen, Kimmo, Tulic, Semir, Skakalova, Viera, Khan, Sabbir A., Laiho, Patrik, Zhang, Qiang, Li, Changfeng, Monazam, Mohammad R. A., Kotakoski, Jani, Lipsanen, Harri, and Kauppinen, Esko I.

Subjects
Physics - Applied Physics
Abstract

Transparent and conductive films (TCFs) are of great technological importance. The high transmittance, electrical conductivity and mechanical strength make single-walled carbon nanotubes (SWCNTs) a good candidate for their raw material. Despite the ballistic transport in individual SWCNTs, however, the electrical conductivity of their networks is limited by low efficiency of charge tunneling between the tube elements. Here, we demonstrate that the nanotube network sheet resistance at high optical transmittance is decreased by more than 50% when fabricated on graphene and thus provides a comparable improvement as widely adopted gold chloride ($\mathrm{AuCl_3}$) doping. However, while Raman spectroscopy reveals substantial changes in spectral features of doped nanotubes, no similar effect is observed in presence of graphene. Instead, temperature dependent transport measurements indicate that graphene substrate reduces the tunneling barrier heights while its parallel conductivity contribution is almost negligible. Finally, we show that combining the graphene substrate and $\mathrm{AuCl_3}$ doping, the SWCNT thin films can exhibit sheet resistance as low as 36 $\Omega$/sq. at 90% transmittance., Comment: 21 pages, 6 figures

Published
2019

26. Upcycled synthesis and extraction of carbon‐encapsulated iron carbide nanoparticles for gap Plasmon applications in perovskite solar cells

Author

Han, Jiye, primary, Kim, Kyusun, additional, Tavakkoli, Mohammad, additional, Lee, Jongmin, additional, Kim, Dawoon, additional, Chung, In, additional, Lee, Aram, additional, Park, Keonwoo, additional, Liao, Yongping, additional, Lee, Jin‐Wook, additional, Lee, Seoung‐Ki, additional, Oh, Jin‐Woo, additional, Sung, Hyokyung, additional, Kauppinen, Esko, additional, and Jeon, Il, additional

Published
2023
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29. Upcycled Synthesis and Extraction of Carbon-Encapsulated Iron Carbide Nanoparticles for Gap Plasmon Applications in Perovskite Solar Cells

Author

Han, Jiye, primary, Kim, Kyusun, additional, Tavakkoli, Mohammad, additional, Lee, Jongmin, additional, Kim, Dawoon, additional, Chung, In, additional, Lee, Aram, additional, Park, Keonwoo, additional, Liao, Yongping, additional, Lee, Jin-Wook, additional, Lee, Seoung-Ki, additional, Oh, Jin-Woo, additional, Sung, Hyokyung, additional, Kauppinen, Esko, additional, and JEON, IL, additional

Published
2022
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34. PDA/PEI-induced in-situ growth of a lotus leaf-like TiO2 nanoparticle film on N-halamine cotton fabric for photocatalytic, self-cleaning and efficient antibacterial performance.

Author

Wan, Jiansheng, Li, Hong, Xu, Lanjie, Yan, Jun, Liao, Yongping, and Wang, Xinyu

Subjects
COTTON textiles, COTTON, NANOPARTICLES, POLYETHYLENEIMINE, NATURAL dyes & dyeing, METHYLENE blue, CONTACT angle, TITANIUM dioxide
Abstract

Functional cotton fabrics with N-halamine structure were prepared by in situ growth of titanium dioxide (TiO2) nanoparticles on PDA/PEI (polydopamine/polyethyleneimine) coating, which effectively solved the problem of bacterial growth and stain adhesion for cotton fabrics. The results of SEM, XRD, and XPS analyses showed that the TiO2 nanoparticles were successfully produced on the surface of the fabric and were spherical at 60 °C. Photoluminescence (PL) spectra showed that PDA and TiO2 were beneficial in improving the electron–hole pairs separation efficiency of the modified fabrics. And the weight percentage of TiO2 nanoparticles deposited on the fabric surface was 14.4% from TG analysis. Photocatalytic experiments showed that the TiO2-deposited cotton fabrics degraded 97.1% of methylene blue (MB) solution within 12 h and had excellent stability. After chlorination, the TiO2-deposited cotton fabrics could sterilize 100% Staphylococcus aureus and Escherichia coli within 30 min, and the TiO2 was able to reduce the chlorine loss of N-halamine upon UV irradiation. By comparing the water contact angles of the TiO2-deposited cotton fabrics at different temperatures, it was found that the TiO2-deposited cotton fabrics at 60 °C have a lotus leaf-like hydrophobic property which brings self-cleaning performance. After loading with TiO2 nanoparticles, the fabrics had desirable cytocompatibility and the breaking strength was also improved. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Synthesis and Extraction of Carbon-Encapsulated Iron Carbide Nanoparticles for Perovskite Solar Cell Application

Author

Han, Jiye, primary, Kim, Kyusun, additional, Tavakkoli, Mohammad, additional, Lee, Jongmin, additional, Kim, Dawoon, additional, Chung, In, additional, Lee, Aram, additional, Park, Sangeun, additional, Park, Keonwoo, additional, Liao, Yongping, additional, Lee, Jin-Wook, additional, Lee, Seoung-Ki, additional, Oh, Jin-Woo, additional, Sung, Hyokyung, additional, Kauppinen, Esko I., additional, and Jeon, Il, additional

Published
2022
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39. Colors of Single-Wall Carbon Nanotubes

Author

Wei, Nan, Tian, Ying, Liao, Yongping, Komatsu, Natsumi, Gao, Weilu, Lyuleeva-Husemann, Alina, Zhang, Qiang, Hussain, Aqeel, Ding, Er Xiong, Yao, Fengrui, Halme, Janne, Liu, Kaihui, Kono, Junichiro, Jiang, Hua, Kauppinen, Esko I., Department of Applied Physics, Dalian Maritime University, NanoMaterials, Rice University, Peking University, Aalto-yliopisto, and Aalto University

Subjects
color range, pigments, quantitative coloration model, carbon nanotube thin films, nanomaterials
Abstract

Although single-wall carbon nanotubes (SWCNTs) exhibit various colors in suspension, directly synthesized SWCNT films usually appear black. Recently, a unique one-step method for directly fabricating green and brown films has been developed. Such remarkable progress, however, has brought up several new questions. The coloration mechanism, potentially achievable colors, and color controllability of SWCNTs are unknown. Here, a quantitative model is reported that can predict the specific colors of SWCNT films and unambiguously identify the coloration mechanism. Using this model, colors of 466 different SWCNT species are calculated, which reveals a broad spectrum of potentially achievable colors of SWCNTs. The calculated colors are in excellent agreement with existing experimental data. Furthermore, the theory predicts the existence of many brilliantly colored SWCNT films, which are experimentally expected. This study shows that SWCNTs as a form of pure carbon, can display a full spectrum of vivid colors, which is expected to complement the general understanding of carbon materials.

Published
2021

40. Carbon Nanotubes: Colors of Single‐Wall Carbon Nanotubes (Adv. Mater. 8/2021)

Author

Wei, Nan, primary, Tian, Ying, additional, Liao, Yongping, additional, Komatsu, Natsumi, additional, Gao, Weilu, additional, Lyuleeva‐Husemann, Alina, additional, Zhang, Qiang, additional, Hussain, Aqeel, additional, Ding, Er‐Xiong, additional, Yao, Fengrui, additional, Halme, Janne, additional, Liu, Kaihui, additional, Kono, Junichiro, additional, Jiang, Hua, additional, and Kauppinen, Esko I., additional

Published
2021
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41. Colors of Single‐Wall Carbon Nanotubes

Author

Wei, Nan, primary, Tian, Ying, additional, Liao, Yongping, additional, Komatsu, Natsumi, additional, Gao, Weilu, additional, Lyuleeva‐Husemann, Alina, additional, Zhang, Qiang, additional, Hussain, Aqeel, additional, Ding, Er‐Xiong, additional, Yao, Fengrui, additional, Halme, Janne, additional, Liu, Kaihui, additional, Kono, Junichiro, additional, Jiang, Hua, additional, and Kauppinen, Esko I., additional

Published
2020
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43. Hybrid Low‐Dimensional Carbon Allotropes Formed in Gas Phase

Author

Ahmad, Saeed, primary, Mustonen, Kimmo, additional, McLean, Ben, additional, Jiang, Hua, additional, Zhang, Qiang, additional, Hussain, Aqeel, additional, Khan, Abu Taher, additional, Ding, Er‐Xiong, additional, Liao, Yongping, additional, Wei, Nan, additional, Monazam, Mohammad R. A., additional, Nasibulin, Albert G., additional, Kotakoski, Jani, additional, Page, Alister J., additional, and Kauppinen, Esko I., additional

Published
2020
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47. Enhanced Tunneling in a Hybrid of Single-Walled Carbon Nanotubes and Graphene

Author

Liao, Yongping, primary, Mustonen, Kimmo, additional, Tulić, Semir, additional, Skákalová, Viera, additional, Khan, Sabbir A., additional, Laiho, Patrik, additional, Zhang, Qiang, additional, Li, Changfeng, additional, Monazam, Mohammad R. A., additional, Kotakoski, Jani, additional, Lipsanen, Harri, additional, and Kauppinen, Esko I., additional

Published
2019
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48. Hybrid X-ray Spectroscopy-Based Approach To Acquire Chemical and Structural Information of Single-Walled Carbon Nanotubes with Superior Sensitivity

Author

Sainio, Sami, primary, Wester, Niklas, additional, Titus, Charles J., additional, Liao, Yongping, additional, Zhang, Qiang, additional, Nordlund, Dennis, additional, Sokaras, Dimosthenis, additional, Lee, Sang-jun, additional, Irwin, Kent D., additional, Doriese, William B., additional, O’Neil, Galen C., additional, Swetz, Daniel S., additional, Ullom, Joel N., additional, Kauppinen, Esko I., additional, Laurila, Tomi, additional, and Koskinen, Jari, additional

Published
2019
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49. Single‐Walled Carbon Nanotubes: Tuning Geometry of SWCNTs by CO 2 in Floating Catalyst CVD for High‐Performance Transparent Conductive Films (Adv. Mater. Interfaces 23/2018)

Author

Liao, Yongping, primary, Hussain, Aqeel, additional, Laiho, Patrik, additional, Zhang, Qiang, additional, Tian, Ying, additional, Wei, Nan, additional, Ding, Er‐Xiong, additional, Khan, Sabbir A., additional, Nguyen, Nguyen Ngan, additional, Ahmad, Saeed, additional, and Kauppinen, Esko I., additional

Published
2018
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50. Investigation of interfaces in AlSb/InAs/Ga0.71In0.29Sb quantum wells by photoluminescence.

Author

Xing Junliang, Zhang Yu, Liao Yongping, Wang Juan, Xiang Wei, Hao Hongyue, Xu Yingqiang, and Niu Zhichuan

Subjects
QUANTUM wells, PHOTOLUMINESCENCE, OPTICAL properties, LASER research, POTENTIAL theory (Physics)
Abstract

We have investigated excitation power and temperature dependent PL spectra to systematically study the influences of the interfaces in the both InAs/Ga0.71In0.29Sb and InAs/AlSb on the optical properties of AlSb/Ga0.71In0.29Sb/InAs quantum wells (QWs). The localized states as well as the activation energy were analyzed to discuss the possible thermal quenching and non-radiative recombination mechanisms. We found two non-radiative recombination processes were involved in the thermal quenching of radiative emission for the QW structures. The GaAs-like interface in InAs/Ga0.71In0.29Sb with higher activation energy (62.7 meV) in high temperature region (70 K-300 K) supplies a deeper hole confinement and less roughness than the InSb-like one, which suppress non-radiative recombination process and promote the optical qualities of the quantum wells. The peak energy of the InSb-like sample exhibited "step-curve" behavior with increase temperature. Neither InSb-like nor AlAs-like interface in InAs/AlSb favored the radiative emission efficiency. [ABSTRACT FROM AUTHOR]

Published
2014
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