Quinizarin-based simple and convenient colorimetric sensor for carbon dioxide

성민석 서울대학교 대학원 2017 국내석사

Abstract Quinizarin-based Simple and Convenient Colorimetric Sensor for Carbon Dioxide MinSeok Seong Department of Materials Science and Engineering The Graduate School Seoul National University In search of simple and fast method to estimate the concentration of atmospheric carbon dioxide, the quinizarin and TBD system was discovered and its mechanism was studied and the applications were tried. From UV-VIS spectrum, the reason behind the change in color of the solution was found to be the different electronic forms of quinizarin. In other words, the color of the quinizarin solution was orange yellow when quinizarin was neutral while its color changed to purple once mixed with TBD as a result of deprotonation. Also, the molar ratio of quinizarin to TBD was 1 to 1 because there was no increase in the strength of the absorption band when TBD was excessive whilst there was a decrease when TBD was deficit. Also, the shift of the absorption band was observed as a result of TBD binding with carbon dioxide and giving back protons to quinizarin. From 1H-NMR spectrum, the hydroxyl proton of quinizarin was observed initially but it was soon given to TBD. Also, the fact that TBD bound itself with carbon dioxide was verified by the 13C-NMR spectrum as a new peak was observed at 161 ppm. In assistance with FT-IR spectrums, the proposed mechanism was supported once more. Quinizarin loses a proton to TBD and the protonated TBD loses the proton as it binds with carbon dioxide. As a result, the color of the solution changed from purple to yellow. The intensity of the vibrational modes for the corresponding functional groups changed accordingly; N-H bond decreased and O-H bond increased. For the experimental parts, the saturation volume of carbon dioxide was studied; the total volumetric capacity of the detecting system at different concentrations were measured and it was used to estimate the approximate response time and detectable concentration of carbon dioxide for each concentration of the system. The response time of the system at given concentration of carbon dioxide was figured out in the next step. As predicted, the system with lower concentrations of the chemicals had a shorter response time. However, the systems with the other organic bases such as DBU and piperidine were found to be not fast enough to detect the concentration of carbon dioxide fast compared to the system with TBD at the same concentration. Most importantly, the system could be recycled for at least 3 to 5 times and the performance was maintained relatively well. The system could actually be re-used upto 10 times but it became harder and harder to notice the color change when re-used too many times. Known the properties of the system as sensor, new applications were tried.. For solidification, TBD was physically fixed onto silica and it was successfully done. Nextly, the solid TBD was dipped in the quinizarin solution to become blue. Although the system was seemingly ready, it was not be able to interact with the atmospheric carbon dioxide and did not undergo any color change. Obviously, the solid system failed to interact with carbon dioxide because of too high thermodynamic barrier between solid and gas. The other option was an Agarose gel technique. The quinizarin and TBD solution was made and mixed with hot agarose solution and cooled down. However, the gel had too much viscosity so the response time was significantly increased. Keywords: Carbon dioxide, Chemical dye, Organic base, Protonation, Deprotonation, Adduct, Colorimetric sensor, Student Number: 2015-20829

Cheminformatics Approaches to Model Hla-Mediated Adverse Drug Reactions, Challenging Protein-Ligand Complexes, and Large Series of Chemical Dyes

Van Den Driessche, George A North Carolina State University ProQuest Dissertat 2019 해외박사(DDOD)

Fabrication of Organic Electrodes Using Conducting Polymers and Graphene and Their Organic Electronic Device Applications

신경환 서울대학교 대학원 2014 국내박사

Organic electronic devices will significantly improve and revolutionize several aspects of our daily life. The most envisaged applications are the displays, lighting modules, and organic photovoltaic cells. Organic electronic devices have considerable advantages in contrast to current devices, such as lightweight, thin, robust, conformable, and flexibility. The performance, efficiency and lifetime of organic electronic devices are greatly affected by the optical, electrical, and structural properties of the organic electrodes. These should meet specific and advanced requirements, such as high optical transparency, ultra low atmospheric gas permeability, electrical conductivity, structural stability, film–substrate adhesion, etc. Electrodes consisted of transparent conductive oxides have attracted a considerable amount of interest and have been extensively investigated. Traditionally, the most common material is indium tin oxide, which has retained its dominance due to superior combination of high optical transparency and low resistance. However, indium tin oxide is also prone to several major problems. The supply of indium is constrained by both mining and geo-political issues; therefore, indium is relatively expensive. Adding to the cost of indium tin oxide is the expense of setting up and maintaining a sputter deposition line, as well as the low deposition yields. In addition to cost, indium tin oxide suffers from being quite brittle, showing cracks at relatively low strains. This is already a problem in many of today’s devices, and promises to be an even bigger issue in future flexible electronics. To make light, unbreakable, flexible, rollable, and fully transparent devices, eventually, it is indispensable that the metal-based components should be replaced with organic materials. This dissertation presents a potential solution of the materials for the electrode of organic electronic devices focusing on conducting polymers and graphene. Solution-processable polyaniline is fabricated by secondary doping with camphorsulfonic acid. The polyaniline solution can be spin-coated onto various substrates including glass, indium tin oxide and flexible polymeric film, which process yields highly conductive polyaniline electrodes successfully. Inkjet printing-mediated vapor deposition polymerization is emerging as a useful method for printing an electrode pattern of nondispersive conducting polymers. An exquisitely patterned polypyrrole electrodes is formed by the technique in top-contact thin film transistor instead of metal electrodes. A novel and reliable approach for the preparation of reduced graphene oxide transparent electrodes is conducted through the combination of chemical and subsequent pressure-assisted thermal reduction at 180°C on a flexible plastic substrate. This reduction process produces reduced graphene oxide electrodes without the transferring or imprinting processes used in conventional synthetic approaches for graphene thin film production. These results strongly suggest that these organic electrodes should be potentially very useful in many new types of applications related to organic electronic devices.

Novel Dye-Sensitized Photocathodes and Semiconductors for Light-Driven Photoelectrochemical Synthesis

Sun, Jiaonan ProQuest Dissertations & Theses The Ohio State Uni 2021 해외박사(DDOD)

To meet the ever-increasing worldwide energy consumption, artificial photosynthesis which converts sustainable solar energy into value-added products has been widely investigated. Compared with well-studied water splitting and CO2 reduction reactions, oxygen reduction reaction for hydrogen peroxide (H2O2) production and photo-electrosynthesis is a lesser-known process. This dissertation details the study in (1) using dye-sensitized photocathodes for oxygen reduction to produce H2O2 efficiently and aprotic redox reactions (2) applying p-type Cu2O semiconductors for the photoelectrochemical synthesis of value-added chemicals.H2O2 is a versatile energy carrier and can be produced by reduction of O2 on a dye-sensitized photocathode. In this dissertation, using a hydrophobic donor-double-acceptor dye (denoted as BH4) sensitized NiO photocathode, H2O2 can be produced efficiently by reducing O2 with current density up to 600 mA cm−2 under 1 sun conditions (Xe lamp as sunlight simulator, wavelength > 400 nm). The dye-sensitized photoelectrochemical cells (DSPECs) maintain currents greater than 200 mA cm−2 at low overpotential (0.42 V vs. RHE) for 18 h with no decrease in the rate of H2O2 production in aqueous electrolyte. Moreover, the BH4 sensitized NiO photocathode was for the first time applied in an aprotic electrolyte for oxygen reduction. The corresponding photocurrent generated by this photoelectrosynthesis is up to 1.8 mA cm−2. Transient absorption spectroscopy also proves that there is an effective electron transfer from reduced BH4 to O2 with a rate constant of 1.8 x 106 s−1. Although using dye-sensitized photocathode shows high current for O2 reduction, the poor faradaic efficiency of H2O2 production and decomposition limit the development of dye-sensitized electrodes. Inspired by the organic synthesis of H2O2 with anthraquinone method and redox mediators used in Li-O2 batteries, anthraquinone (AQ) redox mediators are introduced to metal-free organic DSPECs for the generation of H2O2. Instead of directly reducing O2 to produce H2O2, visible light-driven AQ reduction occurs in the DSPEC and the following autooxidation with O2 allows for H2O2 accumulation and AQ regeneration. This AQ-relay DSPEC exhibits the highest photocurrent so far in non-aqueous electrolyte for H2O2 production and excellent acid stability in aqueous electrolyte, which provides a practical and efficient strategy for visible-light driven H2O2 production. Continuing the study in photoelectrosynthesis, p-type Cu2O photoelectrodes were designed and synthesized by oxidation and thermal annealing approach. Superior performance of the as-synthesized Cu2O as photoelectrodes in both aqueous and non-aqueous electrolyte provides new insight in developing numerous organic synthesis reactions, through a solar- and electricity-driven process. Perovskites with p-i-n structure were applied to photoelectrochemical benzoquinone reduction. Further, anthraquinone molecules with NH2 function groups were proposed and synthesized for surface passivation of perovskites, which provides the opportunity of enhancing catalytic O2 reduction and the fabrication of novel low-dimension halide perovskites.

Enhanced light scattering from SiO2/N doped TiO2 photoelectrodes for Dye-sensitized solar cells

이민준 금오공과대학교 대학원 2017 국내석사

N-doped TiO2 was further doped with SiO2 to prepare SiO2/N-doped TiO2 photoelectrodes with high activity in the visible region. A sol-gel process was employed to produce nanoparticles of SiO2/N-doped TiO2. The addition of SiO2 to the metal oxide enhanced charge transfer and reduced charge recombination. With the addition of sufficient amounts of SiO2 and N, the photoelectrodes exhibited a high surface area and strong absorption of light because of their altered absorptivity in the visible wavelength region. These characteristics enabled the production of photoelectrodes with increased charge transfer and reduced charge recombination, resulting in dye-sensitized solar cells (DSSCs) with enhanced Jsc values. The SiO2/N-doped TiO2 photoelectrodes were characterized using a range of analysis techniques. After the J-V curve measurements, the DSSCs fabricated with the 0.1 mM SiO2/N-doped TiO2 photoelectrodes exhibited the highest energy conversion efficiency of 8.68%, which was approximately 3% higher than that of the N-doped TiO2 control groups. This high energy efficiency with the addition of SiO2 might be due to the enhanced surface area of the photoelectrodes, allowing more dye absorption, and a decrease in electron recombination. 본 연구는 SiO2를 TiO2 전극에 도핑하고 염료감응형 태양전지에 적용하였으며 가시광영역에서 높은 반응성을 나타내는 N를 첨가, SiO2/N doped TiO2를 전극을 제조하였다. SiO2/N doped TiO2 나노입자는 sol-gel method를 이용하여 제조하였으며 전이금속인 SiO2 첨가는 전하이동속도가 증가하고 전자 재결합비율은 감소하였다. 또한 적절한 양의 SiO2와 N을 첨가로 비표면적이 향상되고 염료 흡착과 전자재결합이 감소하여 Jsc(mA/cm2)가 상승하였다. XRD, TEM, EDS, IMPS, IMVS, EIS를 통하여 특성평가를 진행하였으며 I-V curve 측정 결과 0.1mM SiO2/N doped TiO2를 전극으로 사용했을 때, 대조군인 TiO2보다 약 3% 향상된 8.68%로 측정되었다. 이는 비표면적의 증가로 인한 염료 흡착의 증가와 전이금속으로 인한 전자이동도에 따른 전재결합감소 때문이다.

分散/反應染料에 의한 폴리에스테르/綿混紡織物의 나染에 있어 染料의 化學構造와 固着條件이 染着에 미치는 영향

강숙녀 世宗大學校 大學院 1994 국내박사

Enhanced light scattering from SiO2/N doped TiO2 photoelectrodes for Dye-sensitized solar cells

이민준 금오공과대학교 2017 국내석사

Esterification behaviors of phosphorous flame retardants and characterizations of polymers and fibers prepared with them

양승철 서울대학교 대학원 2007 국내박사

Synthesis and Characterization of Ternary Oxide Semiconductor Nanocrystals for Highly Efficient Photon Energy Conversion Devices

김동욱 서울대학교 대학원 2010 국내박사

염색제 중 일부 유해화학물질의 성분분석과 유해물질 표시제도 및 안전의식에 관한 연구

조진아 고려대학교 2005 국내박사

The Study on the Analysis with a part of the Hazard Chemical Materials in the Hair Dyeing and the Labelling System of the Hazard Materials Ingredient and the Safety Recognition Jin-A CHO The hair dyeing products are composed of various chemical materials, and customers and hairdressers are exposed to them without hazard recognition. This study tries to aim the improvement for managing the hazard chemical material use. Firstly it tries to investigate the hazard chemical materials and examine heavy metal contents from lab test. Secondly it compares the accuracy of the indication based on the results from the examination and suggests the solution of the legal regulation problem. Thirdly it applies with the data shown caused factors from the side effects which present surgical operation method against hair dyeing and directs civil official plan and safety education with hairdresser's recognition. Fourthly, it arranges the improvement program and reappraises the program regarding the chemical material use for the purpose of improvement on controlling related to the hair dyeing. 34 types hair dyeing products in market selected contains chemical(synthetic) based and vegetability(natural) based(henna). Also it selected domestic and importing products on positioning the most market share. HPLC method for analysis is applied for chemical ingredients(p-aminophenol, p-phenylenediamine, m-aminophenol and resorcinol) and analyzes heavy metal ion contents(zinc, lead, manganese, cadmium and copper). The survey questionnaire contents are examined hazardousness and damage cases in the hair cosmetic products, symptoms after use, use frequencies, preference between general customer and hairdresser's recognition and hair coloring behavior about hair dyeing. From the test results, the chemical ingredients are mostly defended the legal permission consistency of organic synthesis except resorcinol. The heavy metals are also defended the legal permission consistency except mang