Nanoscience and Nanotechnology | Open Access Articles

An Ultrabroadband 3d Achromatic Metalens, Fatih Balli, Mansoor A. Sultan, Aytekin Ozdemir, J. Todd Hastings

Electrical and Computer Engineering Faculty Publications

We design and fabricate ultra-broadband achromatic metalenses operating from the visible into the short-wave infrared, 450–1700 nm, with diffraction-limited performance. A hybrid 3D architecture, which combines nanoholes with a phase plate, allows realization in low refractive index materials. As a result, two-photon lithography can be used for prototyping while molding can be used for mass production. Experimentally, a 0.27 numerical aperture (NA) metalens exhibits 60% average focusing efficiency and 6% maximum focal length error over the entire bandwidth. In addition, a 200 μm diameter, 0.04 NA metalens was used to demonstrate achromatic imaging over the same broad spectral range. These …

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Enhanced Crystallinity Of Triple-Cation Perovskite Film Via Doping Nh4Scn, Ziji Liu, Detao Liu, Hao Chen, Long Ji, Hualin Zheng, Yiding Gu, Feng Wang, Zhi Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

The trap-state density in perovskite films largely determines the photovoltaic performance of perovskite solar cells (PSCs). Increasing the crystal grain size in perovskite films is an effective method to reduce the trap-state density. Here, we have added NH₄SCN into perovskite precursor solution to obtain perovskite films with an increased crystal grain size. The perovskite with increased crystal grain size shows a much lower trap-state density compared with reference perovskite films, resulting in an improved photovoltaic performance in PSCs. The champion photovoltaic device has achieved a power conversion efficiency of 19.36%. The proposed method may also impact other optoelectronic …

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Advancing The Understanding Of Environmental Transformations, Bioavailability And Effects Of Nanomaterials, An International Us Environmental Protection Agency—Uk Environmental Nanoscience Initiative Joint Program, Mitch M. Lasat, Kian Fan Chung, Jamie Lead, Steve Mcgrath, Richard J. Owen, Sophie Rocks, Jason M. Unrine, Junfeng Zhang

Plant and Soil Sciences Faculty Publications

Nanotechnology has significant economic, health, and environmental benefits, including renewable energy and innovative environmental solutions. Manufactured nanoparticles have been incorporated into new materials and products because of their novel or enhanced properties. These very same properties also have prompted concerns about the potential environmental and human health hazard and risk posed by the manufactured nanomaterials. Appropriate risk management responses require the development of models capable of predicting the environmental and human health effects of the nanomaterials. Development of predictive models has been hampered by a lack of information concerning the environmental fate, behavior and effects of manufactured nanoparticles. The United …

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Optical And Electronic Properties Of Femtosecond Laser-Induced Sulfur-Hyperdoped Silicon N+/P Photodiodes, Ting Zhang, Bohan Liu, Waseem Ahmad, Yaoyu Xuan, Xiangxiao Ying, Zhijun Liu, Zhi David Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

Impurity-mediated near-infrared (NIR) photoresponse in silicon is of great interest for photovoltaics and photodetectors. In this paper, we have fabricated a series of n⁺/p photodetectors with hyperdoped silicon prepared by ion-implantation and femtosecond pulsed laser. These devices showed a remarkable enhancement on absorption and photoresponse at NIR wavelengths. The device fabricated with implantation dose of 10¹⁴ ions/cm² has exhibited the best performance. The proposed method offers an approach to fabricate low-cost broadband silicon-based photodetectors.

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Size And Shape Distributions Of Primary Crystallites In Titania Aggregates, Eric A. Grulke, Kazuhiro Yamamoto, Kazuhiro Kumagai, Ines Häusler, Werner Österle, Erik Ortel, Vasile-Dan Hodoroaba, Scott C. Brown, Christopher Chan, Jiwen Zheng, Kenji Yamamoto, Kouji Yashiki, Nam Woong Song, Young Heon Kim, Aleksandr B Stefaniak, D. Schwegler-Berry, Victoria A. Coleman, Åsa K. Jämting, Jan Herrmann, Toru Arakawa, Woodrow W. Burchett, Joshua W. Lambert, Arnold J. Stromberg

Chemical and Materials Engineering Faculty Publications

The primary crystallite size of titania powder relates to its properties in a number of applications. Transmission electron microscopy was used in this interlaboratory comparison (ILC) to measure primary crystallite size and shape distributions for a commercial aggregated titania powder. Data of four size descriptors and two shape descriptors were evaluated across nine laboratories. Data repeatability and reproducibility was evaluated by analysis of variance. One-third of the laboratory pairs had similar size descriptor data, but 83% of the pairs had similar aspect ratio data. Scale descriptor distributions were generally unimodal and were well-described by lognormal reference models. Shape descriptor distributions …

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Realizing Full Coverage Of Stable Perovskite Film By Modified Anti-Solvent Process, Long Ji, Ting Zhang, Yafei Wang, Peng Zhang, Detao Liu, Zhi David Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

Lead-free solution-processed solid-state photovoltaic devices based on formamidinium tin triiodide (FASnI₃) and cesium tin triiodide (CsSnI₃) perovskite semiconductor as the light harvester are reported. In this letter, we used solvent engineering and anti-solvent dripping method to fabricate perovskite films. SnCl₂ was used as an inhibitor of Sn⁴⁺ in FASnI₃precursor solution. We obtained the best films under the function of toluene or chlorobenzene in anti-solvent dripping method and monitored the oxidation of FASnI₃ films in air. We chose SnF₂as an additive of CsSnI₃ precursor solution to prevent the oxidation …

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Enhanced Performance Of Planar Perovskite Solar Cells Using Low-Temperature Solution-Processed Al-Doped Sno2 As Electron Transport Layers, Hao Chen, Detao Liu, Yafei Wang, Chenyun Wang, Ting Zhang, Peng Zhang, Hojjatollah Sarvari, Zhi Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

Lead halide perovskite solar cells (PSCs) appear to be the ideal future candidate for photovoltaic applications owing to the rapid development in recent years. The electron transport layers (ETLs) prepared by low-temperature process are essential for widespread implementation and large-scale commercialization of PSCs. Here, we report an effective approach for producing planar PSCs with Al³⁺ doped SnO₂ ETLs prepared by using a low-temperature solution-processed method. The Al dopant in SnO₂ enhanced the charge transport behavior of planar PSCs and increased the current density of the devices, compared with the undoped SnO₂ ETLs. Moreover, the enhanced electrical …

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Electronic Properties Of A New All-Inorganic Perovskite Tlpbi3 Simulated By The First Principles, Zhao Liu, Ting Zhang, Yafei Wang, Chenyun Wang, Peng Zhang, Hojjatollah Sarvari, Zhi Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

All-inorganic perovskites have been recognized as promising photovoltaic materials. We simulated the perovskite material of TlPbI₃ using ab initio electronic structure calculations. The band gap of 1.33 eV is extremely close to the theoretical optimum value. Compared TlPbI₃ with CsPbI₃, the total energy (−3980 eV) of the former is much lower than the latter. The partial density of states (PDOS) of TlPbI₃ shows that a strong bond exists between Tl and I, resulting in the lower total energy and more stable existence than CsPbI₃.

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Focused Electron Beam Induced Deposition Of Copper With High Resolution And Purity From Aqueous Solutions, Samaneh Esfandiarpour, Lindsay Boehme, J. Todd Hastings

Electrical and Computer Engineering Faculty Publications

Electron-beam induced deposition of high-purity copper nanostructures is desirable for nanoscale rapid prototyping, interconnection of chemically synthesized structures, and integrated circuit editing. However, metalorganic, gas-phase precursors for copper introduce high levels of carbon contamination. Here we demonstrate electron beam induced deposition of high-purity copper nanostructures from aqueous solutions of copper sulfate. The addition of sulfuric acid eliminates oxygen contamination from the deposit and produces a deposit with ~95 at% copper. The addition of sodium dodecyl sulfate (SDS), Triton X-100, or polyethylene glycole (PEG) improves pattern resolution and controls deposit morphology but leads to slightly reduced purity. High resolution nested lines …

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Efficient Planar Heterojunction Perovskite Solar Cells With Li-Doped Compact Tio2 Layer, Detao Liu, Shibin Li, Peng Zhang, Yafei Wang, Rui Zhang, Hojjatollah Sarvari, Feng Wang, Jiang Wu, Zhiming Wang, Zhi Chen

Electrical and Computer Engineering Faculty Publications

Perovskite solar cells (PSCs) have been developed rapidly in recent time, and efficient planar PSCs are regarded as the most promising alternative to the Si solar cells. In this study, we demonstrated that Li-doping of compact TiO₂ can reduce the density of electron traps and increase the conductivity of the electron transport layer (ETL) of PSCs. Due to the improved electronic property of ETL, the Li-doped compact TiO₂ based planar heterojunction PSCs exhibit negligible hysteretic J-V behavior. Comparing with the undoped compact TiO₂ based PSCs, the power conversion efficiency (PCE) of the Li-doped compact TiO₂ film …

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Reference Compensation For Localized Surface-Plasmon Resonance Sensors, Neha Nehru

Theses and Dissertations--Electrical and Computer Engineering

Noble metal nanoparticles supporting localized surface plasmon resonances (LSPR) have been extensively investigated for label free detection of various biological and chemical interactions. When compared to other optical sensing techniques, LSPR sensors offer label-free detection of biomolecular interactions in localized sensing volume solutions. However, these sensors also suffer from a major disadvantage – LSPR sensors remain highly susceptible to interference because they respond to both solution refractive index change and non-specific binding as well as specific binding of the target analyte. These interactions can severely compromise the measurement of the target analyte in a complex unknown media and hence limit …

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Full-Text Articles in Nanoscience and Nanotechnology

An Ultrabroadband 3d Achromatic Metalens, Fatih Balli, Mansoor A. Sultan, Aytekin Ozdemir, J. Todd Hastings

Electrical and Computer Engineering Faculty Publications

Enhanced Crystallinity Of Triple-Cation Perovskite Film Via Doping Nh4Scn, Ziji Liu, Detao Liu, Hao Chen, Long Ji, Hualin Zheng, Yiding Gu, Feng Wang, Zhi Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

Plant and Soil Sciences Faculty Publications

Optical And Electronic Properties Of Femtosecond Laser-Induced Sulfur-Hyperdoped Silicon N+/P Photodiodes, Ting Zhang, Bohan Liu, Waseem Ahmad, Yaoyu Xuan, Xiangxiao Ying, Zhijun Liu, Zhi David Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

Chemical and Materials Engineering Faculty Publications

Realizing Full Coverage Of Stable Perovskite Film By Modified Anti-Solvent Process, Long Ji, Ting Zhang, Yafei Wang, Peng Zhang, Detao Liu, Zhi David Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

Enhanced Performance Of Planar Perovskite Solar Cells Using Low-Temperature Solution-Processed Al-Doped Sno2 As Electron Transport Layers, Hao Chen, Detao Liu, Yafei Wang, Chenyun Wang, Ting Zhang, Peng Zhang, Hojjatollah Sarvari, Zhi Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

Electronic Properties Of A New All-Inorganic Perovskite Tlpbi3 Simulated By The First Principles, Zhao Liu, Ting Zhang, Yafei Wang, Chenyun Wang, Peng Zhang, Hojjatollah Sarvari, Zhi Chen, Shibin Li

Electrical and Computer Engineering Faculty Publications

Focused Electron Beam Induced Deposition Of Copper With High Resolution And Purity From Aqueous Solutions, Samaneh Esfandiarpour, Lindsay Boehme, J. Todd Hastings

Electrical and Computer Engineering Faculty Publications

Efficient Planar Heterojunction Perovskite Solar Cells With Li-Doped Compact Tio2 Layer, Detao Liu, Shibin Li, Peng Zhang, Yafei Wang, Rui Zhang, Hojjatollah Sarvari, Feng Wang, Jiang Wu, Zhiming Wang, Zhi Chen

Electrical and Computer Engineering Faculty Publications

Reference Compensation For Localized Surface-Plasmon Resonance Sensors, Neha Nehru

Theses and Dissertations--Electrical and Computer Engineering