Development of highly sensitive [Ru(bpy)(3)](2+) - Based optical oxygen sensing thin films in the presence with Fe3O4 and Fe3O4@Ag NPs

Optical sensors based on chemically sensitive matrices/dyes have been used for accurate measurements of oxygen levels. In this study, the intensity-based response of highly sensitive tris(2,2'-bipyridyl) ruthenium(II) chloride [Ru(bpy)(3)](2+) dye to oxygen (O-2) was analyzed in the polymeric ethylcellulose matrix (EC) in the presence of two magnetite forms; Fe3O4 and Fe3O4@Ag nanoparticles (NPs). Fe3O4 NPs were synthesized by flame spray pyrolysis (FSP) and then Fe3O4@Ag NPs were prepared by a core-shell coating method. Iron oxide polymorphs were characterized by using X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It was measured that the particles synthesized by the FSP technique have an average size of 60 nm Fe3O4, Fe3O4@Ag NPs, and 1-butyl-3-methylimidazolium tetrafluoroborate; ([BMIM][BF4]) were used as additives for enhancement of the sensitivity of the [Ru(bpy)(3)](2+) dye to O-2 gas. The effects of these additive materials were examined by photoluminescence spectroscopy (PL). [Ru(bpy)(3)](2+) dye doped nanofiber in the presence with the Fe3O4@Ag NPs additive yielded higher Stern-Volmer constant (K-SV) and extended linear response range when compared with the sensing slides in the presence with Fe3O4 NPs and the additive-free forms. The higher response ratio (I-0/I-100) was found as 3.45 for the ruthenium dye doped EC nanofiber form in the presence with Fe3O4@Ag NPs. Also, KSV values were calculated as 2.41 x 10(-2) between the concentration range of 0-100% [O-2]. According to our knowledge, it is the first time Fe3O4 and Fe3O4@Ag NPs were used for the enhancement of oxygen sensitivity of the ruthenium dye

LU3AL5O12:CE3+ VE CA-Α-SIALON:EU2+ OPTİK ÖZELLİKLERİNİN KİNİN SÜLFATLA ARTTIRILMASI

LU3AL5O12:CE3+ VE CA-Α-SIALON:EU2+ OPTİK ÖZELLİKLERİNİN KİNİN SÜLFATLA ARTTIRILMASIUtku ULUCAN, Kadriye ERTEKİN, Sibel OĞUZLARTürkiyeÖz: Bugüne kadar Eu2+ doplu Ca-α-Sialon ve Ce3+ doplanmış LuAG: Ce3+ polimerik matris içerisinde geniş bir şekilde çalışılmıştır. Diğer yanda Kinin Sülfat kuantuum verimi standartı olarak kullanılmıştır ve ayrıca çok iyi emisyon performansı olduğu için başka amaçlar içinde oldukça çalışılmıştır. Bu çalışmada ise , ilk kez Ca-α-Sialon: Eu2+/QS ve LuAG: Ce3+/QS fosforlarının polimetil metakrilat (PMMA) matris içersindeki eksitasyon ve emisyon davranışlarını inceliyeceğiz. Ca-α-Sialon: Eu2+ % 44 emisyon intensity artışı göstermiştir. Benzer olarak LuAG: Ce3+ Kinin sülfat karışımı ise % 98 parlaklık artışını PMMA matriste göstermiştir. Buda kinin sülfatın fosforlarla etkileşime girerk onların emisyon vede eksitasyon özelliklerinin en iyi şekilde arttırdığını göstermiştir. Kinin sülfat LuAG: Ce3+ ve Ca-α-Sialon'nun en iyi şekilde floresans özelliklerinin arttırmış ve onlardan çok daha iyi bir eksitasyon ve emisyon pikleri almamızı sağlamıştır.Decay time ölçümlei mikro ve nano saniye cinsinden yapılmıştır ve Kinin Sülfatla fosforlar arasındaki potansiyel enerji transferleri araştırılmıştır. Decay time ölçümlerinde kinin sülfatla kullanılan fosforlar arsında aktarılan enerji transferinin fosforlar kinin sülfat içerisinde arttırıldıkça kademeli olarak arttığı görülmüştür. Bu çalışma sayesinde maliyeti düşürülerek ampüllerde, televizyon ekranlarında, monitörlerde, akıllı telefonlarda ve elektronik aletlerin panellerinde görüntünün iyileştirilmesi sağlanmaya çalışılmıştır. Bu çalışmada genel olarak kinin Sülfatın fosforlarla etkileşime girip enerji transferleri sayesinde eksitasyon ve emisyon piklerini arttırdığını gözlemlemiş olduk.Anahtar Kelimeler: Ca-α-Sialon: Eu2+, LuAG: Ce3+, Kinin Sülfat, Floresans</p

Improvement of CO2 response: Effect of SnO2 and Ni-doped SnO2 semiconductors on HPTS-basedprobes

Accurate, continuous and precise monitoring of dissolved and gaseous carbondioxide(CO2) is vital in industrial, chemical, medical and atmosphericanalysis. In this study, SnO2 and Ni-doped SnO2 powderswere added as additives to increase gas sensitivity to8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) dye, which is a commercialfluorescent indicator with high sensitivity to CO2 gas.Characterizations of synthesized metal oxide semiconductors (MOSs) wereperformed using photoluminescence spectroscopy (PL), X-ray photoelectronspectroscopy (XPS), X-ray diffraction spectroscopy (XRD) and scanning electronmicroscope (SEM). HPTS-based thin films were prepared by immobilizing dye andMOSs additives to ethyl cellulose (EC) matrix. Steady-state measurements, decaytime kinetics and kinetic measurements of the sensor agents were measured inthe concentration range of 0-100% [CO2]. The addition of SnO2-basedsemiconductors to the HPTS-based composites has resulted in many improvements insensor dynamics such as higher sensitivity, relative signal variation andlarger linear response range according to the additive-free form. The CO2sensitivities of HPTS dye were measured as 4.7, 12.6 and 57.5 fold for theundoped and SnO2 and Ni-doped SnO2 doped forms,respectively. The response and recovery times of the HPTS-based sensing slideagainst CO2 with Ni-doped SnO2 powders were measured as 38and 156 s. These results make the HPTS fluorophore with SnO2 and Ni-doped SnO2additives into more advanced sensor agents for sensitivity to CO2gas and show it as a promising candidate for CO2 probes.</p

Enhancement of CO2 response of HPTS along with TiO2 NPs and TiO2@Ag NPs

In chemical, industrial, medical, biochemical andclinical analysis, the continuous and accurate detection of dissolved and/orgaseous CO2 is very important. In recent studies, 8-hydroxypyrene-1, 3,6-trisulfonic acid (HPTS) dye,which is a pH sensitive fluorescent indicator with high sensitivity to CO2gas, is preferred. Researches relating to the improvement of gas sensitivity ofHPTS-based optical sensors are very popular. The aim of this study is toenhance the CO2 response of HPTS along with the sol-gel synthesized TiO2and TiO2@Ag nanoparticles (NPs) as additives. Thecharacterizations of the synthesized metal oxide powders were carried outthrough XPS, XRD, FT-IR, SEM, and PL spectroscopy. The sensing slides were prepared in the form of a thinfilm by immobilizing the HPTS dye and TiO2 and TiO2@Ag NPs additives into theethyl cellulose polymer matrix. Steady state and decay time based spectralresponses of the HPTS-based composites were measured as analytical signal in the concentration range of 0–100% [CO2]. Additions ofTiO2-based additives to HPTS resulted in many advances such as highrelative signal change and larger linear response range, improved sensordynamics, and higher sensitivity with respect to the additive-free forms. Whereasthe CO2 sensitivities were measured as %39, 52% and 70% for undopedform and TiO2 andTiO2@Ag NPs doped forms of the HPTS-based thin films, respectively. The response and the recovery times of the HPTS-basedsensing slide along with TiO2@AgNPs have been measured as 15 and 45 s. These resultsmake the HPTS along with the metal oxide additives promising candidates as CO2probes.</p