scholarly journals Organic Dye-Doped PMMA Lasing

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3566
Author(s):  
Pen Yiao Ang ◽  
Marko Čehovski ◽  
Frederike Lompa ◽  
Christian Hänisch ◽  
Dinara Samigullina ◽  
...  

Organic thin-film lasers gain interest as potential light sources for application in diverse fields. With the current development, they hold variety of benefits such as: low-cost, high-performance, and color-tunability. Meanwhile, the production is not complicated because both the resonator and the gain medium can be assembled by solution-processable organic materials. To our knowledge, information about using poly(methyl methacrylate) (PMMA) as a matrix for organic dye lasers was insubstantial. Herein, the feasibility of using organic dye-doped PMMA as an organic dye laser was tested. Six different sample designs were introduced to find out the best sample model. The most optimum result was displayed by the sample design, in which the gain medium was sandwiched between the substrate and the photoresist layer with grating structure. The impact of dye concentration and grating period on peak wavelength was also investigated, which resulted in a shift of 6 nm and 25 nm, respectively. Moreover, there were in total six various organic dyes that could function well with PMMA to collectively perform as ’organic dye lasers’, and they emitted in the range of 572 nm to 609 nm. Besides, one of the samples was used as a sensor platform. For instance, it was used to detect the concentration of sugar solutions.

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jun Yin ◽  
Lian Liu ◽  
Yashu Zang ◽  
Anni Ying ◽  
Wenjie Hui ◽  
...  

AbstractHere, an engineered tunneling layer enhanced photocurrent multiplication through the impact ionization effect was proposed and experimentally demonstrated on the graphene/silicon heterojunction photodetectors. With considering the suitable band structure of the insulation material and their special defect states, an atomic layer deposition (ALD) prepared wide-bandgap insulating (WBI) layer of AlN was introduced into the interface of graphene/silicon heterojunction. The promoted tunneling process from this designed structure demonstrated that can effectively help the impact ionization with photogain not only for the regular minority carriers from silicon, but also for the novel hot carries from graphene. As a result, significantly enhanced photocurrent as well as simultaneously decreased dark current about one order were accomplished in this graphene/insulation/silicon (GIS) heterojunction devices with the optimized AlN thickness of ~15 nm compared to the conventional graphene/silicon (GS) devices. Specifically, at the reverse bias of −10 V, a 3.96-A W−1 responsivity with the photogain of ~5.8 for the peak response under 850-nm light illumination, and a 1.03-A W−1 responsivity with ∼3.5 photogain under the 365 nm ultraviolet (UV) illumination were realized, which are even remarkably higher than those in GIS devices with either Al2O3 or the commonly employed SiO2 insulation layers. This work demonstrates a universal strategy to fabricate broadband, low-cost and high-performance photo-detecting devices towards the graphene-silicon optoelectronic integration.


2021 ◽  
Vol 2125 (1) ◽  
pp. 011001

We are glad to introduce you that the 2021 4th International Conference on Mechanical, Electrical and Material Application (MEMA 2021) was successfully held on October 29-31, 2021. In light of worldwide travel restriction and the impact of COVID-19, MEMA 2021 was carried out in the form of virtual conference to avoid personnel gatherings. Because most participants were still highly enthusiastic about participating in this conference, we chose to carry out MEMA 2021 via online platform according to the original schedule instead of postponing it. MEMA 2021 is to bring together innovative academics and industrial experts in the field of Mechanical, Electrical and Material Application to a common forum. The primary goal of the conference is to promote research and developmental activities in Mechanical, Electrical and Material Application and another goal is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working all around the world. The conference will be held every year to make it an ideal platform for people to share views and experiences in Mechanical, Electrical and Material Application and related areas. We were greatly honored to invited Prof. Kun Li, from Chongqing University, China and Assoc. Prof. Wei Wei, from Xi’an University of Technology, China as our Conference Chairmen. This scientific event brings together more than 100 national and international researchers in mechanical, electrical and material application. During the conference, the conference model was divided into three sessions, including oral presentations, keynote speeches, and online Q&A discussion. In the first part, some scholars, whose submissions were selected as the excellent papers, were given about 5-10 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches. We were pleased to invite four distinguished experts to present their insightful speeches. Our first keynote speaker, Prof. Shahid Hussain, Jiangsu University, China. His research interests include MOS-MOF-MXene Nanomaterials, Gas-Sensors, Electrochemical Supercapacitors, Li-S batteries. And then we had Prof. Jie Huang, from Southwest University, China. His research includes RF/Microwave circuits and sensors. Prof. Qiyan Xu, Anhui University of Technology, China. His main research directions are: New process and technology of low cost steel making, Direct reduction and melting reduction, Development of new metallurgical technology - comprehensive utilization of waste resources. Lastly, we were glad to invite Prof. Kun Li, Chongqing University, China. He mainly engaged in additive manufacturing, intelligent 3D net forming, high performance materials and phase transformation, material computing and other research. In the last part of the conference, all participants were invited to join in a WeChat group to discuss and explore the academic issues after the presentations. The online discussion was lasted for about 30-60 minutes. We are glad to share with you that we still received lots of submissions from the conference during this special period. Hence, we selected a bunch of high-quality papers and compiled them into the proceedings after rigorously reviewed them. These papers feature following topics but are not limited to: Mechanical Dynamics and its Applications, Material Physics, Electrical and Electronic Systems and other related topics. All the papers have been through rigorous review and process to meet the requirements of International publication standard. Lastly, we would like to express our sincere gratitude to the Chairman, the distinguished keynote speakers, as well as all the participants. We also want to thank the publisher for publishing the proceedings. May the readers could enjoy the gain some valuable knowledge from the proceedings. We are expecting more and more experts and scholars from all over the world to join this international event next year. The Committee of MEMA 2021 List of Committee member is available in this pdf.


Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 842 ◽  
Author(s):  
Yanqing Fu ◽  
Qiliang Wei ◽  
Gaixia Zhang ◽  
Yu Zhong ◽  
Nima Moghimian ◽  
...  

In this work, we investigated three types of graphene (i.e., home-made G, G V4, and G V20) with different size and morphology, as additives to a lithium iron phosphate (LFP) cathode for the lithium-ion battery. Both the LFP and the two types of graphene (G V4 and G V20) were sourced from industrial, large-volume manufacturers, enabling cathode production at low cost. The use of wrinkled and/or large pieces of a graphene matrix shows promising electrochemical performance when used as an additive to the LFP, which indicates that the features of large and curved graphene pieces enable construction of a more effective conducting network to realize the full potential of the active materials. Specifically, compared to pristine LFP, the LFP/G, LFP/G V20, and LFP/G V4 show up to a 9.2%, 6.9%, and 4.6% increase, respectively, in a capacity at 1 C. Furthermore, the LFP combined with graphene exhibits a better rate performance than tested with two different charge/discharge modes. Moreover, from the economic and electrochemical performance view point, we also demonstrated that 1% of graphene content is optimized no matter the capacity calculated, based on the LFP/graphene composite or pure LFP.


Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2493
Author(s):  
Junlong Yao ◽  
Hanchao Hu ◽  
Zhengguang Sun ◽  
Yucong Wang ◽  
Huabo Huang ◽  
...  

In order to overcome the challenge of synchronously strengthening and toughening polypropylene (PP) with a low-cost and environmental technology, CaCO3 (CC) nanoparticles are modified by tartaric acid (TA), a kind of food-grade complexing agent, and used as nanofillers for the first time. The evaluation of mechanical performance showed that, with 20 wt.% TA-modified CC (TAMCC), the impact toughness and tensile strength of TAMCC/PP were 120% and 14% more than those of neat PP, respectively. Even with 50 wt.% TAMCC, the impact toughness and tensile strength of TAMCC/PP were still superior to those of neat PP, which is attributable to the improved compatibility and dispersion of TAMCC in a PP matrix, and the better fluidity of TAMCC/PP nanocomposite. The strengthening and toughening mechanism of TAMCC for PP involves interfacial debonding between nanofillers and PP, and the decreased crystallinity of PP, but without the formation of β-PP. This article presents a new applicable method to modify CC inorganic fillers with a green modifier and promote their dispersion in PP. The obtained PP nanocomposite simultaneously achieved enhanced mechanical strength and impact toughness even with high content of nanofillers, highlighting bright perspective in high-performance, economical, and eco-friendly polymer-inorganic nanocomposites.


Author(s):  
Ethan Swierski ◽  
Molly Burke ◽  
Maria Arenas ◽  
Jessica Bernat ◽  
James Manzer ◽  
...  

Abstract Due to the impact gait impairments have on afflicted individuals’ lives, there are many efforts to find effective remedies. One example is drop foot, a condition in which the dorsiflexion in the leg falters, and the forefront of the foot drags during walking. One of these is the use of an Ankle Foot Orthosis (AFO), a device worn on the lower extremity of the leg to improve walking ability. Although these orthoses have been improved over time to address a user’s physical needs, material and financial restrictions are still an obstacle. To find the lowest cost AFO design of high performance, a study was conducted to investigate the applications of a simplified design process for an AFO. The design process is a fast, low cost, easy technique of laser cutting thermoplastic resin and bending a drawing into a 3-dimensional AFO. Finding the best AFO possible using this design process was easy, involving making a 2-dimensional CAD model for laser cutting, performing Finite Element Analysis (FEA) simulations and comparing a variety of designs, materials, and configurations for their ability to improve a user’s gait kinematics while also meeting optimal cost and comfort needs.


Author(s):  
D. L. Palmer ◽  
W. F. Waterman

This paper describes the aero-mechanical design and development of a 3.3 kg/sec (7.3 lb/sec), 14:1 pressure ratio two-stage centrifugal compressor which is used in the T800-LHT-800 helicopter engine. The design employs highly nonradial, splitter bladed impellers with swept leading edges and compact vaned diffusers to achieve high performance in a small and robust configuration. The development effort quantified the effects of impeller diffusion and passive inducer shroud bleed on surge margin as well as the effects of impeller loading on tip clearance sensitivity and the impact of sand erosion and shroud roughness on performance. The developed compressor exceeded its performance objectives with a minimum of 23-percent surge margin without variable geometry. The compressor provides a high performance, rugged, low-cost configuration ideally suited for helicopter applications.


2012 ◽  
Vol 1435 ◽  
Author(s):  
Robert Mueller ◽  
Steve Smout ◽  
Myriam Willegems ◽  
Jan Genoe ◽  
Paul Heremans

ABSTRACTShort channel organic thin film transistors in bottom-gate, bottom contact configuration use typically gold metallization for the source and drain contacts because this metal can easily be cleaned from photoresist residuals by oxygen plasma or ultraviolet-ozone and allows also surface modification by self-assembled monolayers (e.g. thiols). Alternative low-cost bottom contact metallization for high performance short-channel organic thin film transistors are scarce because of the incompatibility of the bottom contact material with the cleaning step. In this work a new process flow, involving a temporary thin aluminum protection layer, is presented. Short channel (3.4 μm) pentacene transistors with lithographical defined and thiol modified silver source/drain bottom contacts (25 nm thick, on a 2 nm titanium adhesion layer) prepared according to this process achieved a saturation mobility of 0.316 cm2/(V.s), and this at a metal cost below 1% of the standard 30 nm thick gold metallization.


Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6695
Author(s):  
Dirk Johannes De Beer ◽  
Trudi-Heleen Joubert

Impedance spectroscopy is a widely used electrochemical technique with a wide variety of applications. Many of these applications benefit from the additional accessibility provided by low-cost impedance devices. With this in mind, a low-cost impedance device was designed for a high performance-to-cost ratio. The performance of this analyzer was validated against a high-performance DropSens µStat-i 400s potentiostat by performing an application-based experiment. Nitrate detection provides a relevant experiment because of the importance of maintaining precise nitrate concentrations to mitigate the impact of nitrate fluctuations on the environment. Dissolved nitrate samples of different concentrations, in the range 3–1000 mg/L, were confirmed colorimetrically and measured with both instruments. A calibration curve of the real impedance matched a sigmoidal transfer, with a linear region for concentrations below 10 mg/L. The device under investigation exhibited an average magnitude error of 1.28% and an average phase error of 0.96∘ relative to the high-performance standard, which validates the performance of the low-cost device. A cost analysis is presented that highlights some of the complexities of cost comparisons.


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