Yi-Te Chuang, Yu-Chieh Li, Ting‐Mao Feng, Chun-Ta Wang
Liquid crystal polarization gratings liquid crystal Pancharatnam‐Berry phase optical element (LCPGs) are a superior alternative to traditional diffraction gratings due to their high diffraction efficiency, strong polarization sensitivity, and versatile tunability. This paper introduces an electrically switchable liquid crystal polarization grating based on cholesteric liquid crystals (CLCs). The LCPG is designed to operate in reflective (R‐mode) and transmissive (T‐mode) states. It utilizes the standing helical (SH) configuration of CLCs for reflective functionality and transitions to a lying helical (LH) configuration for transmissive operations. This dual‐mode capability is achieved through a unique application of electric fields, which reorient the liquid crystal helix axis according to the desired optical function. The performance of the LCPG in both R‐mode and T‐mode is evaluated by applying different frequencies and voltages to dynamically switch between the helical states. The manufacturing process is simple, and the device performs robustly. This suggests that the technology could be useful for developing optical systems that require dynamic control over light modulation.
液晶偏振光栅液晶Pancharatnam-Berry相光学元件（LCPGs）具有高衍射效率、强偏振灵敏度和多功能可调性，是传统衍射光栅的优越替代品。本文介绍了一种基于胆甾型液晶（CLCs）的电动可切换液晶偏振光栅。LCPG 可在反射（R 模式）和透射（T 模式）状态下工作。它利用 CLC 的站立螺旋（SH）配置实现反射功能，并过渡到躺卧螺旋（LH）配置实现透射功能。这种双模功能是通过独特的电场应用实现的，电场可根据所需的光学功能调整液晶螺旋轴的方向。通过应用不同的频率和电压在螺旋状态之间进行动态切换，对 LCPG 在 R 模式和 T 模式下的性能进行了评估。制造工艺简单，器件性能稳定。这表明该技术可用于开发需要对光调制进行动态控制的光学系统。
{"title":"Electrically Switchable Transmissive and Reflective Liquid Crystal Polarization Gratings Based on Cholesteric Liquid Crystals","authors":"Yi-Te Chuang, Yu-Chieh Li, Ting‐Mao Feng, Chun-Ta Wang","doi":"10.1002/admt.202400726","DOIUrl":"https://doi.org/10.1002/admt.202400726","url":null,"abstract":"Liquid crystal polarization gratings liquid crystal Pancharatnam‐Berry phase optical element (LCPGs) are a superior alternative to traditional diffraction gratings due to their high diffraction efficiency, strong polarization sensitivity, and versatile tunability. This paper introduces an electrically switchable liquid crystal polarization grating based on cholesteric liquid crystals (CLCs). The LCPG is designed to operate in reflective (R‐mode) and transmissive (T‐mode) states. It utilizes the standing helical (SH) configuration of CLCs for reflective functionality and transitions to a lying helical (LH) configuration for transmissive operations. This dual‐mode capability is achieved through a unique application of electric fields, which reorient the liquid crystal helix axis according to the desired optical function. The performance of the LCPG in both R‐mode and T‐mode is evaluated by applying different frequencies and voltages to dynamically switch between the helical states. The manufacturing process is simple, and the device performs robustly. This suggests that the technology could be useful for developing optical systems that require dynamic control over light modulation.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuna Kim, Byunglib Jung, Md Mobaidul Islam, Byeonggwan Kim, Jin Jang
Low‐power electronic devices are of increasing interest with high‐k gate insulators (GI). Herein, the performance and stability of low‐temperature poly‐Si (LTPS) thin‐film transistors (TFTs) are investigated with two different GIs: spray pyrolyzed zirconiumaluminum oxide (ZAO) directly deposited on poly‐Si, and SiO2/ZAO stack GI. The LTPS TFT with SiO2/ZAO stack GI exhibits hysteresis free characteristics with a threshold voltage of −0.2 V, field‐effect mobility of 114.4 cm2 V−1 s−1, subthreshold swing of 0.10 V dec−1, and high on/off current ratio of 7.3 × 108, at a gate voltage sweeping ±6 V. The TFT exhibits very stable operation under negative bias temperature stress. The X‐ray photoelectron spectroscopy and high‐resolution transmission electron microscopy analyses demonstrate that the diffusion of Zr and Al into poly‐Si deteriorates device performance with ZAO only GI. A thin SiO2 on LTPS blocks the diffusion of Zr and Al, resulting the high‐performance and stable p‐type LTPS TFT with a high‐k SiO2/ZAO stack GI. Finally, a 7‐stage ring oscillator using LTPS TFTs with SiO2/ZAO stack GI is demonstrated, exhibiting an oscillation frequency of 7.49 MHz and a propagation delay of 9.54 ns at a supply voltage of 6 V, indicating its suitability for low‐power consumption TFT electronics and displays.
采用高 K 栅极绝缘体 (GI) 的低功耗电子器件越来越受到关注。本文研究了使用两种不同栅极绝缘体的低温多晶硅（LTPS）薄膜晶体管（TFT）的性能和稳定性：直接沉积在多晶硅上的喷雾热解氧化锆（ZAO）和二氧化硅/ZAO叠层栅极绝缘体。采用 SiO2/ZAO 叠层 GI 的 LTPS TFT 具有无滞后特性，阈值电压为 -0.2 V，场效应迁移率为 114.4 cm2 V-1 s-1，阈下摆幅为 0.10 V dec-1，在栅极电压为 ±6 V 时具有 7.3 × 108 的高导通/关断电流比。X 射线光电子能谱和高分辨率透射电子显微镜分析表明，由于 Zr 和 Al 扩散到多晶硅中，导致器件性能下降，只有 GI 采用了 ZAO。LTPS 上的薄二氧化硅阻挡了锆和铝的扩散，从而产生了具有高 k SiO2/ZAO 叠层 GI 的高性能、稳定的 p 型 LTPS TFT。最后，展示了使用具有 SiO2/ZAO 叠层 GI 的 LTPS TFT 的 7 级环形振荡器，在 6 V 电源电压下，振荡频率为 7.49 MHz，传播延迟为 9.54 ns，表明它适用于低功耗 TFT 电子产品和显示器。
{"title":"Low‐Temperature Poly‐Si Thin‐Film Transistor with High‐k ZrAlOx Gate Insulator with SiO2 Blocking Layer","authors":"Yuna Kim, Byunglib Jung, Md Mobaidul Islam, Byeonggwan Kim, Jin Jang","doi":"10.1002/admt.202400820","DOIUrl":"https://doi.org/10.1002/admt.202400820","url":null,"abstract":"Low‐power electronic devices are of increasing interest with high‐k gate insulators (GI). Herein, the performance and stability of low‐temperature poly‐Si (LTPS) thin‐film transistors (TFTs) are investigated with two different GIs: spray pyrolyzed zirconiumaluminum oxide (ZAO) directly deposited on poly‐Si, and SiO2/ZAO stack GI. The LTPS TFT with SiO2/ZAO stack GI exhibits hysteresis free characteristics with a threshold voltage of −0.2 V, field‐effect mobility of 114.4 cm2 V−1 s−1, subthreshold swing of 0.10 V dec−1, and high on/off current ratio of 7.3 × 108, at a gate voltage sweeping ±6 V. The TFT exhibits very stable operation under negative bias temperature stress. The X‐ray photoelectron spectroscopy and high‐resolution transmission electron microscopy analyses demonstrate that the diffusion of Zr and Al into poly‐Si deteriorates device performance with ZAO only GI. A thin SiO2 on LTPS blocks the diffusion of Zr and Al, resulting the high‐performance and stable p‐type LTPS TFT with a high‐k SiO2/ZAO stack GI. Finally, a 7‐stage ring oscillator using LTPS TFTs with SiO2/ZAO stack GI is demonstrated, exhibiting an oscillation frequency of 7.49 MHz and a propagation delay of 9.54 ns at a supply voltage of 6 V, indicating its suitability for low‐power consumption TFT electronics and displays.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. N. F. Moreira Filho, Matheus Xavier de Oliveira, Ana Lorena Brito Soares, Lidyane Souto Maciel Marques, Pascale Chevallier, Diego Mantovani, J. P. Andrade Feitosa, Rodrigo Silveira Vieira
Evaluating the biodegradability and biocompatibility of hydrogels is essential for identifying materials suitable for biomedical applications. This study describes the fabrication of hydrogels utilizing physiological‐soluble chitosan (N‐succinyl chitosan, NSC) crosslinked with dialdehyde guar gum (Oxidized Galactomannan, OxGM) via the Schiff‐base reaction. Hydrogels with varying volumetric ratios of NSC/OxGM, resulting in distinct NH2/CHO functional group ratios and crosslinking degrees, underwent comprehensive characterization using Fourier‐transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), swelling, and scanning electron microscopy (SEM). Gelation time (tgel) is assessed by rheological analysis (tgel = G′ > G″), where tgel increased with higher crosslinking density, reaching a maximum value of ≈80 s. Biodegradation analysis in phosphate‐buffered saline (PBS) with lysozyme (13 mg L−1) revealed that the crosslinking degree significantly influenced degradation, with lower crosslinking associated with an elevated degradation profile. Moreover, cell viability assays with fibroblastic cells demonstrated minimal cytotoxicity, but an increase in free aldehyde groups correlated with decreased cell viability. For the 75C25C hydrogel, the compressive test yielded a Young's modulus value of 67.2 kPa (±8.5). These results imply that the hydrogels developed exhibit favorable biodegradability and biocompatibility, making them promising candidates for diverse biomedical applications.
{"title":"Impact of Crosslinking Degree on Chitosan and Oxidized Guar Gum‐Based Injectable Hydrogels for Biomedical Applications","authors":"R. N. F. Moreira Filho, Matheus Xavier de Oliveira, Ana Lorena Brito Soares, Lidyane Souto Maciel Marques, Pascale Chevallier, Diego Mantovani, J. P. Andrade Feitosa, Rodrigo Silveira Vieira","doi":"10.1002/admt.202400285","DOIUrl":"https://doi.org/10.1002/admt.202400285","url":null,"abstract":"Evaluating the biodegradability and biocompatibility of hydrogels is essential for identifying materials suitable for biomedical applications. This study describes the fabrication of hydrogels utilizing physiological‐soluble chitosan (N‐succinyl chitosan, NSC) crosslinked with dialdehyde guar gum (Oxidized Galactomannan, OxGM) via the Schiff‐base reaction. Hydrogels with varying volumetric ratios of NSC/OxGM, resulting in distinct NH2/CHO functional group ratios and crosslinking degrees, underwent comprehensive characterization using Fourier‐transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), swelling, and scanning electron microscopy (SEM). Gelation time (tgel) is assessed by rheological analysis (tgel = G′ > G″), where tgel increased with higher crosslinking density, reaching a maximum value of ≈80 s. Biodegradation analysis in phosphate‐buffered saline (PBS) with lysozyme (13 mg L−1) revealed that the crosslinking degree significantly influenced degradation, with lower crosslinking associated with an elevated degradation profile. Moreover, cell viability assays with fibroblastic cells demonstrated minimal cytotoxicity, but an increase in free aldehyde groups correlated with decreased cell viability. For the 75C25C hydrogel, the compressive test yielded a Young's modulus value of 67.2 kPa (±8.5). These results imply that the hydrogels developed exhibit favorable biodegradability and biocompatibility, making them promising candidates for diverse biomedical applications.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiahong Zhou, Mengya Liu, Xudong Xue, Shan Liu, G. Yu
The interlayer twist is a new degree of freedom for forming moiré superlattices in 2D vertical heterostructures, which is expected to play an important role in the emerging field of twistronics. The constructions of heterostructures by transfer and re‐stacking way have low efficiency and are prone to causing interface pollution. In this study, vertical molybdenum diselenide (WSe2)/graphene heterostructures with twisted angles are realized by using two‐step chemical vapor deposition (CVD) growth strategy. The WSe2/graphene heterostructures exhibit Raman and photoluminescence (PL) responses of both WSe2 and graphene. The PL quenching of WSe2 in the heterostructures manifests that direct CVD growth is conducive to the formation of a cleaner interlayer interface between WSe2 and graphene layers, resulting in better interlayer coupling. The adhesion and surface potential differences indicate the formation of hetero‐bilayer stacks. By analyzing the apparent growth orientations and crystal diffractions, vertical WSe2/graphene heterostructures exhibit a wide range of interlayer twisted angles (3.6–46.5°). The difference between the growth behavior with twisted angles and the typical epitaxial growth mode may originate from the heterogeneous nucleation, leading to interlayer twists of the hetero‐bilayers. These findings provide a facile protocol for the preparations of twisted hetero‐bilayers and a material system for fundamental research of twistronics.
{"title":"Chemical Vapor Deposition Growth of Vertical Graphene/WSe2 Heterostructures with Interlayer Twists","authors":"Xiahong Zhou, Mengya Liu, Xudong Xue, Shan Liu, G. Yu","doi":"10.1002/admt.202400901","DOIUrl":"https://doi.org/10.1002/admt.202400901","url":null,"abstract":"The interlayer twist is a new degree of freedom for forming moiré superlattices in 2D vertical heterostructures, which is expected to play an important role in the emerging field of twistronics. The constructions of heterostructures by transfer and re‐stacking way have low efficiency and are prone to causing interface pollution. In this study, vertical molybdenum diselenide (WSe2)/graphene heterostructures with twisted angles are realized by using two‐step chemical vapor deposition (CVD) growth strategy. The WSe2/graphene heterostructures exhibit Raman and photoluminescence (PL) responses of both WSe2 and graphene. The PL quenching of WSe2 in the heterostructures manifests that direct CVD growth is conducive to the formation of a cleaner interlayer interface between WSe2 and graphene layers, resulting in better interlayer coupling. The adhesion and surface potential differences indicate the formation of hetero‐bilayer stacks. By analyzing the apparent growth orientations and crystal diffractions, vertical WSe2/graphene heterostructures exhibit a wide range of interlayer twisted angles (3.6–46.5°). The difference between the growth behavior with twisted angles and the typical epitaxial growth mode may originate from the heterogeneous nucleation, leading to interlayer twists of the hetero‐bilayers. These findings provide a facile protocol for the preparations of twisted hetero‐bilayers and a material system for fundamental research of twistronics.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141921544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xinyao Zhang, Yuxiang Su, Xin Dong, Jinlin Wu, Xiaonan Su, Guanyu Dai, Anguo Liu, Wuwei Feng, Keyang Zhao, Bangjun Lei, Zhenhua Li
The ocean is regarded as a significant resource for renewable energy development. The use of triboelectric nanogenerators (TENGs) provides an effective approach to capturing energy from low‐frequency, random, and disorganized water waves. In this paper, the solid–liquid elastic pendulum (SLEP)‐TENG is designed for omnidirectional blue energy harvesting applications. Differentiating from traditional designs, the proposed TENG has a simple, reliable, and durable flexible pendulum structure with a spherical shell and a solid counterweight at the bottom that can absorb the impact of ocean waves efficiently. The structure also has a hollow hexagonal space that allows it to generate a larger contact area when it is subjected to wave impacts from different directions. Under low‐speed lateral motion conditions (at frequencies below 0.83 Hz), its open‐circuit voltage VOC, short circuit current ISC, and power density Pm can reach up to 486.8 V, 16.9 µA, and 10.26 W m−3, respectively, which is sufficient to power more than 450 commercial light‐emitting diodes. By storing electrical power in small capacitors, the TENG can support small power‐consuming devices, e.g., thermometers and calculators. Therefore, the SLEP‐TENG has great potential for use in combination with Internet of Things devices to enable self‐powered sensing system construction in complex ocean areas.
{"title":"Solid–Liquid Elastic Pendulum Triboelectric Nanogenerator Design for Application to Omnidirectional Blue Energy Harvesting","authors":"Xinyao Zhang, Yuxiang Su, Xin Dong, Jinlin Wu, Xiaonan Su, Guanyu Dai, Anguo Liu, Wuwei Feng, Keyang Zhao, Bangjun Lei, Zhenhua Li","doi":"10.1002/admt.202400531","DOIUrl":"https://doi.org/10.1002/admt.202400531","url":null,"abstract":"The ocean is regarded as a significant resource for renewable energy development. The use of triboelectric nanogenerators (TENGs) provides an effective approach to capturing energy from low‐frequency, random, and disorganized water waves. In this paper, the solid–liquid elastic pendulum (SLEP)‐TENG is designed for omnidirectional blue energy harvesting applications. Differentiating from traditional designs, the proposed TENG has a simple, reliable, and durable flexible pendulum structure with a spherical shell and a solid counterweight at the bottom that can absorb the impact of ocean waves efficiently. The structure also has a hollow hexagonal space that allows it to generate a larger contact area when it is subjected to wave impacts from different directions. Under low‐speed lateral motion conditions (at frequencies below 0.83 Hz), its open‐circuit voltage VOC, short circuit current ISC, and power density Pm can reach up to 486.8 V, 16.9 µA, and 10.26 W m−3, respectively, which is sufficient to power more than 450 commercial light‐emitting diodes. By storing electrical power in small capacitors, the TENG can support small power‐consuming devices, e.g., thermometers and calculators. Therefore, the SLEP‐TENG has great potential for use in combination with Internet of Things devices to enable self‐powered sensing system construction in complex ocean areas.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141928659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Alves, Gemma Quinn, M. Strain, E. G. Durmusoglu, M. Sharma, H. Demir, Paul R. Edwards, Robert W. Martin, M. D. Dawson, N. Laurand
This study introduces and compares the lasing performance of micron‐sized and sphere‐shaped supraparticle (SP) lasers fabricated through bottom‐up assembly of II‐VI semiconductor colloidal quantum wells (CQWs) with their counterparts made of quantum dots (CQDs). CQWs consist of a 4‐monolayers thick CdSe core and an 8‐monolayers thick CdxZn1‐xS shell with a nominal size of 14 × 15 × 4.2 nm, and CQDs of CdSxSe1‐x/ZnS with 6 nm diameter. SPs are optically characterized with a 0.76 ns pulse laser (spot size: 2.88 × 10−7 cm2) at 532 nm, and emit in the 620–670 nm spectral range. Results show that CQW SPs have lasing thresholds twice as low (0.1–0.3 nJ) as CQD SPs (0.3–0.6 nJ), and stress tests using a constant 0.6 nJ optical pump energy demonstrate that CQW SPs withstand lasing emission for longer than CQD SPs. Lasing emission in CQW and CQD SPs under continuous operation yields half‐lives of τCQW SP ≈150 min and τCQD SP ≈22 min, respectively. The half‐life of CQW SPs is further extended to τQW ≈385 min when optically pumped at 0.5 nJ. Such results compare favorably to those in the literature and highlight the performance of CdSe‐based CQW SPs for laser applications.
{"title":"Colloidal Semiconductor Quantum Well Supraparticles as Low‐Threshold and Photostable Microlasers","authors":"P. Alves, Gemma Quinn, M. Strain, E. G. Durmusoglu, M. Sharma, H. Demir, Paul R. Edwards, Robert W. Martin, M. D. Dawson, N. Laurand","doi":"10.1002/admt.202401152","DOIUrl":"https://doi.org/10.1002/admt.202401152","url":null,"abstract":"This study introduces and compares the lasing performance of micron‐sized and sphere‐shaped supraparticle (SP) lasers fabricated through bottom‐up assembly of II‐VI semiconductor colloidal quantum wells (CQWs) with their counterparts made of quantum dots (CQDs). CQWs consist of a 4‐monolayers thick CdSe core and an 8‐monolayers thick CdxZn1‐xS shell with a nominal size of 14 × 15 × 4.2 nm, and CQDs of CdSxSe1‐x/ZnS with 6 nm diameter. SPs are optically characterized with a 0.76 ns pulse laser (spot size: 2.88 × 10−7 cm2) at 532 nm, and emit in the 620–670 nm spectral range. Results show that CQW SPs have lasing thresholds twice as low (0.1–0.3 nJ) as CQD SPs (0.3–0.6 nJ), and stress tests using a constant 0.6 nJ optical pump energy demonstrate that CQW SPs withstand lasing emission for longer than CQD SPs. Lasing emission in CQW and CQD SPs under continuous operation yields half‐lives of τCQW SP ≈150 min and τCQD SP ≈22 min, respectively. The half‐life of CQW SPs is further extended to τQW ≈385 min when optically pumped at 0.5 nJ. Such results compare favorably to those in the literature and highlight the performance of CdSe‐based CQW SPs for laser applications.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141928381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shiyu Zhou, Hao Guo, Bo Qian, Lingying Li, Xuejun Shi
Flexible, tunable‐focus artificial compound eyes (ACEs) have been extensively studied due to their large field of view (FOV), variable focal length, and large depth of field. The fabrication of flexible polydimethylsiloxane (PDMS) microlens arrays (MLAs) is a key issue for this system. Due to the difficulty of directly precision‐machining PDMS, PDMS MLAs typically need molds, which involve complex, costly, and hard‐to‐control methods like laser fabrication and lithography. In this paper, a moldless, single‐step inkjet printing method for PDMS MLAs is proposed. By optimizing the rheological properties of the PDMS ink and adjusting printing waveforms, voltages, and frequencies, this study achieves, for the first time, large‐scale inkjet printing fabrication of PDMS MLAs. The surface morphologies of the microlenses are uniformly consistent, resembling spherical caps. Subsequently, the optimized printed PDMS MLA film is bonded to a microfluidic chip to fabricate a hydraulically driven, variable‐focus ACE with the FOV tunable between 0° and 140° and the focal length tunable from 6 mm to infinity. The ACE is demonstrated to image the objects at various distances by altering the volume of the injected liquid and possessing good optical imaging quality.
{"title":"Single‐Step Inkjet Printing PDMS Microlens Arrays for Tunable‐Focus Artificial Compound Eyes","authors":"Shiyu Zhou, Hao Guo, Bo Qian, Lingying Li, Xuejun Shi","doi":"10.1002/admt.202400016","DOIUrl":"https://doi.org/10.1002/admt.202400016","url":null,"abstract":"Flexible, tunable‐focus artificial compound eyes (ACEs) have been extensively studied due to their large field of view (FOV), variable focal length, and large depth of field. The fabrication of flexible polydimethylsiloxane (PDMS) microlens arrays (MLAs) is a key issue for this system. Due to the difficulty of directly precision‐machining PDMS, PDMS MLAs typically need molds, which involve complex, costly, and hard‐to‐control methods like laser fabrication and lithography. In this paper, a moldless, single‐step inkjet printing method for PDMS MLAs is proposed. By optimizing the rheological properties of the PDMS ink and adjusting printing waveforms, voltages, and frequencies, this study achieves, for the first time, large‐scale inkjet printing fabrication of PDMS MLAs. The surface morphologies of the microlenses are uniformly consistent, resembling spherical caps. Subsequently, the optimized printed PDMS MLA film is bonded to a microfluidic chip to fabricate a hydraulically driven, variable‐focus ACE with the FOV tunable between 0° and 140° and the focal length tunable from 6 mm to infinity. The ACE is demonstrated to image the objects at various distances by altering the volume of the injected liquid and possessing good optical imaging quality.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141929406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Utzeri, Marco Sasso, Vikram S. Deshpande, Shanmugam Kumar
Additive Manufacturing (AM) empowers the creation of high‐performance cellular materials, underscoring the increasing need for programmable and predictable energy absorption capabilities. This study evaluates the impact of a precisely tuned fused filament fabrication (FFF) process on the energy absorption and failure characteristics of 2D‐thermoplastic lattice materials through multiscale experiments and predictive modeling. Macroscale in‐plane compression testing of both thick‐ and thin‐walled lattices, along with their µ‐CT imaging, reveal relative density‐dependent damage mechanisms and failure modes, prompting the development of a robust predictive modeling framework to capture process‐induced performance variation and damage. For lower relative density lattices, an FE model based on the extended Drucker–Prager material model, incorporating Bridgman's correction with crazing failure criteria, accurately captures the crushing response. As lattice density increases, interfacial damage along bead‐bead interfaces becomes predominant, necessitating the enrichment of the model with a microscale cohesive zone model to capture interfacial debonding. The predictive modeling introduces an enhancement factor, offering a straightforward method to assess the impact of the AM process on energy absorption performance, thereby facilitating the inverse design of FFF‐printed lattices. This approach provides a critical evaluation of how FFF processes can be optimized to achieve the highest attainable performance and mitigate failures in architected materials.
增材制造（AM）技术有助于制造高性能的蜂窝材料，强调了对可编程和可预测能量吸收能力的日益增长的需求。本研究通过多尺度实验和预测建模，评估了精确调整的熔融长丝制造（FFF）工艺对二维热塑晶格材料的能量吸收和失效特性的影响。厚壁和薄壁晶格的宏观面内压缩测试及其 µ-CT 成像揭示了与相对密度相关的损坏机制和失效模式，从而促使开发出一种稳健的预测建模框架，以捕捉工艺引起的性能变化和损坏。对于相对密度较低的晶格，基于扩展德鲁克-普拉格材料模型的有限元模型结合布里奇曼校正和裂纹失效标准，可以准确捕捉破碎响应。随着晶格密度的增加，珠粒-珠粒界面上的界面破坏成为主要现象，因此有必要使用微尺度内聚区模型来丰富模型，以捕捉界面脱粘现象。预测模型引入了一个增强因子，提供了一种直接的方法来评估 AM 工艺对能量吸收性能的影响，从而促进了 FFF 印刷晶格的逆向设计。这种方法对如何优化 FFF 工艺以实现最高性能和减少架构材料的失效进行了重要评估。
{"title":"Multiscale Experiments and Predictive Modeling for Failure Mitigation in Additive Manufacturing of Lattices","authors":"M. Utzeri, Marco Sasso, Vikram S. Deshpande, Shanmugam Kumar","doi":"10.1002/admt.202400457","DOIUrl":"https://doi.org/10.1002/admt.202400457","url":null,"abstract":"Additive Manufacturing (AM) empowers the creation of high‐performance cellular materials, underscoring the increasing need for programmable and predictable energy absorption capabilities. This study evaluates the impact of a precisely tuned fused filament fabrication (FFF) process on the energy absorption and failure characteristics of 2D‐thermoplastic lattice materials through multiscale experiments and predictive modeling. Macroscale in‐plane compression testing of both thick‐ and thin‐walled lattices, along with their µ‐CT imaging, reveal relative density‐dependent damage mechanisms and failure modes, prompting the development of a robust predictive modeling framework to capture process‐induced performance variation and damage. For lower relative density lattices, an FE model based on the extended Drucker–Prager material model, incorporating Bridgman's correction with crazing failure criteria, accurately captures the crushing response. As lattice density increases, interfacial damage along bead‐bead interfaces becomes predominant, necessitating the enrichment of the model with a microscale cohesive zone model to capture interfacial debonding. The predictive modeling introduces an enhancement factor, offering a straightforward method to assess the impact of the AM process on energy absorption performance, thereby facilitating the inverse design of FFF‐printed lattices. This approach provides a critical evaluation of how FFF processes can be optimized to achieve the highest attainable performance and mitigate failures in architected materials.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141796931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuteng Liu, Tingting Luo, Chengbiao Ding, Lei Xuan, Jian Li, Runhuai Yang
Athletes continuously seek out creative methods and technologies to improve their physical fitness and overall performance. Wearable technology's progress offers a swift and eco‐conscious way to consistently observe physiological changes evidenced by biomarkers, stemming from an athlete's internal exertion or external workload. However, there is still a long distance to further understand the internal physiology of athletes which may bring hope to tailor training and recovery programs individually. The ongoing challenges faced by sports healthcare personnel are in finding biomarkers safely and continuously to control athletes' physical condition and tailor their recovery and eating patterns. The summary of this review encompasses the development of flexible and wearable electrochemical sensors. This article provides an overview of biofluids, commonly detected by wearable biochemical sensors and their mutual anatomical formations, with a focus on sweat and its associated biomarkers. Following this, its real‐world application in sports medicine becomes apparent, both theoretically and potentially. The paper ends by highlighting challenges and imagining the possible development of this exciting emerging field.
{"title":"Progress in The Application of Flexible and Wearable Electrochemical Sensors in Monitoring Biomarkers of Athletes","authors":"Yuteng Liu, Tingting Luo, Chengbiao Ding, Lei Xuan, Jian Li, Runhuai Yang","doi":"10.1002/admt.202400619","DOIUrl":"https://doi.org/10.1002/admt.202400619","url":null,"abstract":"Athletes continuously seek out creative methods and technologies to improve their physical fitness and overall performance. Wearable technology's progress offers a swift and eco‐conscious way to consistently observe physiological changes evidenced by biomarkers, stemming from an athlete's internal exertion or external workload. However, there is still a long distance to further understand the internal physiology of athletes which may bring hope to tailor training and recovery programs individually. The ongoing challenges faced by sports healthcare personnel are in finding biomarkers safely and continuously to control athletes' physical condition and tailor their recovery and eating patterns. The summary of this review encompasses the development of flexible and wearable electrochemical sensors. This article provides an overview of biofluids, commonly detected by wearable biochemical sensors and their mutual anatomical formations, with a focus on sweat and its associated biomarkers. Following this, its real‐world application in sports medicine becomes apparent, both theoretically and potentially. The paper ends by highlighting challenges and imagining the possible development of this exciting emerging field.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141357491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the era of big data, traditional computing architectures face limitations in handling vast amounts of data owing to the separate processing and memory units, thus causing bottlenecks and high‐energy consumption. Inspired by the human brain's information exchange mechanism, neuromorphic computing offers a promising solution. Resistive random access memory devices, particularly those with bilayer structures like Pt/TaOx/TiOx/TiN, show potential for neuromorphic computing owing to their simple design, low‐power consumption, and compatibility with existing technology. This study investigates the synaptic applications of Pt/TaOx/TiOx/TiN devices for neuromorphic computing. The unique coexistence of nonfilamentary and filamentary switching in the Pt/TaOx/TiOx/TiN device enables the realization of reservoir computing and the functions of artificial nociceptors and synapses. Additionally, the linkage between artificial nociceptors and synapses is examined based on injury‐enhanced spike‐time‐dependent plasticity paradigms. This study underscores the Pt/TaOx/TiOx/TiN device's potential in neuromorphic computing, providing a framework for simulating nociceptors, synapses, and learning principles.
{"title":"Nociceptor‐Enhanced Spike‐Timing‐Dependent Plasticity in Memristor with Coexistence of Filamentary and Non‐Filamentary Switching","authors":"Dongyeol Ju, Jungwoo Lee, Sungjun Kim","doi":"10.1002/admt.202400440","DOIUrl":"https://doi.org/10.1002/admt.202400440","url":null,"abstract":"In the era of big data, traditional computing architectures face limitations in handling vast amounts of data owing to the separate processing and memory units, thus causing bottlenecks and high‐energy consumption. Inspired by the human brain's information exchange mechanism, neuromorphic computing offers a promising solution. Resistive random access memory devices, particularly those with bilayer structures like Pt/TaOx/TiOx/TiN, show potential for neuromorphic computing owing to their simple design, low‐power consumption, and compatibility with existing technology. This study investigates the synaptic applications of Pt/TaOx/TiOx/TiN devices for neuromorphic computing. The unique coexistence of nonfilamentary and filamentary switching in the Pt/TaOx/TiOx/TiN device enables the realization of reservoir computing and the functions of artificial nociceptors and synapses. Additionally, the linkage between artificial nociceptors and synapses is examined based on injury‐enhanced spike‐time‐dependent plasticity paradigms. This study underscores the Pt/TaOx/TiOx/TiN device's potential in neuromorphic computing, providing a framework for simulating nociceptors, synapses, and learning principles.","PeriodicalId":504693,"journal":{"name":"Advanced Materials Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141123449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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