Production of sensitive gas sensors using CuO/SnO2 nanoparticles

Metal oxide nanoparticles, such as CuO and SnO2, are outstanding systems for H2S gas sensing in air. In this work, those nanoparticles were deposited with different mixing percentages on substrates to form percolating networks of nanoparticles. Electrical electrodes were deposited on the nanoparticles’ films to investigate their gas sensing response against H2 and H2S, and their electrical characteristics. The sensor devices based on CuO–SnO2 nanoparticles revealed enhanced sensing characteristics against H2S with a sensitivity of 10 ppm. The enhanced sensing characteristics could be attributed to the formation of PN-junctions among CuO and SnO2 nanoparticles. The reasonable production cost (due to simple structure and cheap used materials), low power consumption ( ~ 1 µW for H2S at room temperature), high sensitivity, high response, and reasonable response time of the present sensors qualify them for practical implementation in portable gas sensing devices with enhanced characteristics.Open Access funding provided by the Qatar National Library. This work was supported by both Qatar National Research Fund (QNRF) under a Grant Number UREP21-035-2-013, and Qatar University fund under a Grant Number QUCG-CAS-20182019-1. The SEM/EDS measurements were accomplished in the Central Laboratories unit at Qatar University. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations

Complex-impedance response of an Ag/TeO2-V2O5/Ag structure

The ac conductivity of glass samples of composition 50 mol% TeO2 and 50 mol% V2O5 has been analyzed. The samples were prepared by the usual melt-quench method. The electrical conductance and capacitance were measured over a frequency range of 20 Hz to 1 MHz and a temperature range of 293–450 K; these reveal semiconducting features based predominantly on an ionic mechanism. This is reflected in a low-frequency Cole–Cole dependence z″ (z′) for the impedance and in a linear dependence ″(′) for the dielectric constant throughout the temperature range. The dielectric and complex-impedance response of the structure measured is discussed. The relaxation time τ0 was found to decrease with increasing temperature. An equivalent circuit was proposed and its parameters calculated. Good agreement between a double-layer physical model and the parameters of the equivalent electrical circuit was obtained

Study on ferroelastic characteristics of gamma irradiated lithium potassium sulfate crystal

A detailed study of the optical absorption vs. γ-irradiation dose for lithium potassium sulfate crystal, LiKSO4 cut out perpendicular to x, y and z directions is presented. The optical density was measured within the wavelength range from 200 to 600 nm at different γ-doses up to 300 kGy. The investigated optical parameters, e.g., absorption coefficient, relative absorbance and optical energy gap, were found to be gamma dose dependent as well as crystal orientation. The results were discussed in the view of interaction of point imperfections, introduced by irradiation, with the ferroelastic behavior of LiKSO4 crystal

انتشار طور التحول في بللورات ذات نسب تكوين مختلفة من ثنائي كبريتات الليثوم والروبيديوم

The influence of changing the ratio of Li2S04 on the structure transition of (RbxLi1-x)2S04 , LRS crystals, where x ranged from 0.1 to 0. 7, was studied by thermal analysis techniques in the temperature range 300 - 600 K. Multiple peaks in the DT A traces were observed for crystals having x = 0.1 and x = 0.2. The values of CP decreased while that ofT, increased with increasing Rb+ content. The excess of the specific heat for LRS crystals showed a broadening in the temperature dependence especially for samples enriched with Rb+. These results could be considered on the development of the ordering of SO4 and Li04 and in their arrangement.تم دراسة تأثير تغير نسبة كبريتات الليثوم على التحول البللوري لبللورات من النظام 2 so4(Rbxli1-x)حيث x تتراوح بين 0.1-0.7 ‏وذلك باستخدام جهاز التحليل الحراري في مدى درجات الحرارة 300-600 ‏درجة مطلقة . أظهرت التجارب المعملية وجود قمم متعددة في منحني التحليل الحراري التفاضلي للبلورات التي تحتوي على x=0.1,0.2 من الروبيديوم ، كما وجد أن قيمة الحرارة النوعية تحت ضغط ثابت تقل بينما درجة حرارة التحول الطوري تزداد مع زيادة كمية الروبيديوم كما لوحظ أن التغير في الحرارة النوعية مع درجة الحرارة يصبح أكثر اتساعا وبصفة خاصة للبلورات التي بها كميات كبيرة من الروبيديوم . وهذه النتائج يمكن اعتبارها إعادة توزيع Loi4,so4 داخل الهيكل البللوري

On the preparation of electron sensor using LiRbSO4 samples

The dielectric spectroscopy of metal�metal sulfate LiRbSO4 samples are described with particular emphasis on sensor performance to be used in the field of radiation. The obtained results as the effect of different electron energy beams at fixed dose, 0.5 Gy, showed abrupt change of the electrical properties (electrical conductivity, capacitance, and loss tangent). The results can be explained on the basis of radiation-induced defects followed by radiation quenching. The prepared samples can be used in the field of radiation dosimeter.Wiley Online Librar

تأثير كل من المجال الكهربي وأشعة جاما على الخواص الضوئية لمادة البولي ايثلين منخفض الكثافة

The effect of electric field and gamma radiation on the optical properties of low density polyethylene LDPE grade CD 0230 have been studied. The samples were irradiated at gamma doses of 0-100 Mrad and varying electric field of 0-104 V/cm. The optical absorption spectra were measured in the wavelength range of 200-1100 nm. The opticl absorption coefficient a and the energy gap A E values were found to be gamma dose dependent. Also these optical parameters show a dependence on the electric field. The change in the polymer crystallinity due to irradiation can be attributed to the induced bond scission and subsequent crosslinking.درست الخواص الضوئية لعينات من مادة البولي ايثلين منخفض الكثافة من النوع 0230 CD والمستعمل في عمل العزل الخارجي لأسلاك التوصيل الكهربي ، عرضت العينات لجرعات اشعاعية في مدى صفر- 100 ميجاراد ومجال كهربي صفر-410 فولت / سم وتم قياس طيف الامتصاص في مدى طول موجي 200 - 1100 نانومتر. أظهرت النتائج أن كل من معامل الامتصاص واتساع الفجوة يكون معتمدا على جرعة الإشعاع كما أن البارامترات الضوئية تتغير أسيا مع شدة المجال الكهربي . فسرت هذه النتائج على أساس كل من التكسير واعادة التشابك والتوزيع الذري بفعل المجال المؤثر

Production of sensitive gas sensors using CuO/SnO2 nanoparticles

Metal oxide nanoparticles, such as CuO and SnO2, are outstanding systems for H2S gas sensing in air. In this work, those nanoparticles were deposited with different mixing percentages on substrates to form percolating networks of nanoparticles. Electrical electrodes were deposited on the nanoparticles’ films to investigate their gas sensing response against H2 and H2S, and their electrical characteristics. The sensor devices based on CuO–SnO2 nanoparticles revealed enhanced sensing characteristics against H2S with a sensitivity of 10 ppm. The enhanced sensing characteristics could be attributed to the formation of PN-junctions among CuO and SnO2 nanoparticles. The reasonable production cost (due to simple structure and cheap used materials), low power consumption ( ~ 1 µW for H2S at room temperature), high sensitivity, high response, and reasonable response time of the present sensors qualify them for practical implementation in portable gas sensing devices with enhanced characteristics.Other Information Published in: Applied Physics A License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s00339-019-2856-6</p