Synthesis and Characterization of Zno Nanoparticles Using Hydrothermal and Sol-Gel Techniques for Dye-Sensitized Solar Cells

في هذا البحث تم تخليق جسيمات نانوية نقية من أكسيد الزنك باستخدام طريقتي الهيدروثيرمال وطريقة الصول جل. من فحوصات حيود الاشعة السينية تبين أن متوسط حجم الحبيبة تتراوح بين من 25 الي 28 نانومتر وتاخذ شكلا كرويا. فحوصات طيف الامتصاص بينت أن العينات جميعها لها اعلي امتصاص في منطقة الاشعة الفوق بنفسجية. وتم حساب فجوة الطاقة للعينات فوجد انها تساوي 3.13 eV و3.16 eV للعينة التي حضرت بطريقة الهيدروثيرمال والصول جل على الترتيب. تم تحضير عينات لخلايا شمسية صبغية وتم استخدام 3 انواع من الاصباغ الكيمياءية كمتحسسات ضوئية. فحوصات الاشعة الفوق بنفسجية بينت ان صبغة الايوزين الاصفر   Eosin Yتعطي اعلي امتصاص مقارنة بالاصباغ المستخدمة الاخري. تم رسم منحني الخواص لجميع العينات للخلايا الشمسية المحضرة وتم حساب جميع البارامترات اللازمة لتقييم اداء الخلية. العينة المصبوغة بصبغةEosin Y اعطت اعلي كفاءة Jsc = 4.25 (mA/cm2)، Voc = 0.51 V and η=1.08 %ZnO nanoparticles (ZnO NPs) were synthesized using hydrothermal and sol-gel techniques using zinc acetate dihydrate (Zn (CH3COO)2.2H2O) as a row material and methanol as a solvent. The structural properties of ZnO NPs were studied using EDX, XRD, TEM, and the optical properties were characterized using UV-VIS and PL spectroscopies. The synthesized ZnO NPs showed high purity and revealed a wurtzite (hexagonal) crystal structure with particle size (D) ranged from 25 nm to 28 nm. The UV-VIS absorption spectra of ZnO NPs samples and sensitizing dyes were performed. The obtained ZnO NPs exhibited the direct optical bandgap 3.15 eV. Dye-sensitized solar cells (DSSCs) were fabricated using synthesized ZnO NPs as a semiconducting layer, which was dyed with different low cost dyes such as Eosin B (EB), Eosin Y (EY) and Rhodamine B (RB) that was used to sensitize the photoanode (ZnO NPs). The experimental results showed a significant efficiency for the fabricated DSSCs of synthesized ZnO NPs via sol gel technique comparing to hydrothermal technique. The EY dye exhibited the best performance among others, where a conversion efficiency showed a noteworthy improvement from 0.12 to 1.08 %

Synthesis and characterization of ZnO nanoparticles using sol gel technique for dye sensitized solar cells applications

ZnO nanoparticles were synthesized using sol gel technique at differentcalcination temperature. The effect of calcination temperature on the structure and opticalproperties of ZnO NPs were studied in detail by using different techniques, X-raydiffraction, high-resolution transmission electron microscope, UV-VIS spectroscopy andphotoluminescence spectroscopy.X-ray diffractionanalysis revealed that the ZnO NPs werecrystalized in a wurtzite structure and the estimated average particle size increased from24.7 to40.4 nm with increasingcalcinationtemperature. In addition, the d spacingincreased from 0.28196 nm to 0.28213 nm.High-resolution transmission electronmicroscopy analysisimage showed spherical ZnONPs were formed. UV-VIS absorptionmeasurement was employed to evaluate the absorption edge and the optical band gapusingTauc plot. Energy gaprevealed a red shift from 3.15 to 2.96 eV when thecalcinationtemperaturewas increased. Dye sensitized solar cells were fabricated using synthesizedZnO NPs as a semiconducting layer that were dyed withdifferentXanthene(CH2[C6H4]2O)dyesseparately;(Eosin B, Eosin Y and Rhodamine B) which arelow costdyes. Thin layer of ZnO were deposited on transparentfluorine doped tin oxideconductiveglass using doctor blade method. Eosin Y exhibited the bestphotosensitizing. Theconversion efficiency showed a significant improvement from 0.1% to 1.08%.This research activity carried out between Gaza-Palestine and Cairo-Egypt, which was financially supported by Qatar Charity IBHATH Project grant funded by the Gulf Cooperation Council for the Reconstruction of Gaza through the Islamic Development Bank.ZnO nanoparticles were synthesized using sol gel technique at differentcalcination temperature. The effect of calcination temperature on the structure and opticalproperties of ZnO NPs were studied in detail by using different techniques, X-raydiffraction, high-resolution transmission electron microscope, UV-VIS spectroscopy andphotoluminescence spectroscopy.X-ray diffractionanalysis revealed that the ZnO NPs werecrystalized in a wurtzite structure and the estimated average particle size increased from24.7 to40.4 nm with increasingcalcinationtemperature. In addition, the d spacingincreased from 0.28196 nm to 0.28213 nm.High-resolution transmission electronmicroscopy analysisimage showed spherical ZnONPs were formed. UV-VIS absorptionmeasurement was employed to evaluate the absorption edge and the optical band gapusingTauc plot. Energy gaprevealed a red shift from 3.15 to 2.96 eV when thecalcinationtemperaturewas increased. Dye sensitized solar cells were fabricated using synthesizedZnO NPs as a semiconducting layer that were dyed withdifferentXanthene(CH2[C6H4]2O)dyesseparately;(Eosin B, Eosin Y and Rhodamine B) which arelow costdyes. Thin layer of ZnO were deposited on transparentfluorine doped tin oxideconductiveglass using doctor blade method. Eosin Y exhibited the bestphotosensitizing. Theconversion efficiency showed a significant improvement from 0.1% to 1.08%

Performance evaluation of five ELISA kits for detecting anti-SARS-COV-2 IgG antibodies

ObjectivesTo evaluate and compare the performances of five commercial ELISA assays (EDI, AnshLabs, Dia.Pro, NovaTec, and Lionex) for detecting anti-SARS-CoV-2 IgG. Methods70 negative control samples (collected before the COVID-19 pandemic) and samples from 101 RT-PCR-confirmed SARS-CoV-2 patients (collected at different time points from symptoms onset: ≤7, 8-14, and >14 days) were used to compare the sensitivity, specificity, agreement, positive and negative predictive values of each assay with RT-PCR. A concordance assessment between the five assays was also conducted. Cross-reactivity with other HCoV, non-HCoV respiratory viruses, non-respiratory viruses, and nuclear antigens was investigated. ResultsLionex showed the highest specificity (98.6%, 95%CI: 92.3-99.8), followed by EDI and Dia.Pro (97.1%, 95%CI: 90.2-99.2), NovaTec (85.7%, 95%CI: 75.7-92.1), then AnshLabs (75.7%, 95%CI: 64.5-84.2). All ELISA kits cross-reacted with one anti-MERS IgG positive sample except Lionex. The sensitivity was low during the early stages of the disease but improved over time. After 14 days from symptoms onset, Lionex and NovaTec showed the highest sensitivity at 87.9% (95%CI: 72.7-95.2) and 86.4% (95%CI: 78.5-91.7), respectively. The agreement with RT-PCR results based on Cohen’s kappa was as follows: Lionex (0.89)> NovaTec (0.70)> Dia.Pro (0.69)> AnshLabs (0.63)> EDI (0.55). ConclusionThe Lionex ELISA, which measures antibodies solely to the S1 protein, demonstrated the best performance.This work was made possible by grant No. RRC-2-032 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. GKN would like to acknowledge funds from Qatar University's internal grant QUERG-CMED-2020-2

Synthesis of Zinc Oxide nanoparticles at different aging time for low cost Dye Sensitized Solar Cells

Zinc oxide nanoparticles synthesized via simple precipitation method and aged at different time were used as photoanodes of dye sensitized solar cells (DSSCs). The structural and the optical properties of the obtained zinc oxide nanoparticles were investigated. The performance of the assembled solar cells was studied and the efficiency of such cell was compared as a relation of the aging time of the ZnO nanoparticles.Zinc oxide nanoparticles synthesized via simple precipitation method and aged at different time were used as photoanodes of dye sensitized solar cells (DSSCs). The structural and the optical properties of the obtained zinc oxide nanoparticles were investigated. The performance of the assembled solar cells was studied and the efficiency of such cell was compared as a relation of the aging time of the ZnO nanoparticles

استخدام جسيمات اكسيد الزنك النانوية كقطب سالب للخلايا الشمسية

ZnO nanoparticles (NPs) were synthesized using solution combustion method with different urea percent (UP) i.e. U1, U2, U3 and U4. The obtained ZnO NPs were characterized using X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), UV–Vis spectroscopy and photoluminescence spectroscopy (PL). XRD analysis confirmed the wurtzite structure of the prepared ZnO NPs and the estimated average crystallite size reduced from 28.03 nm to 17.33 nm with increasing of UP. HR-TEM image showed an irregular spherical shape for the prepared ZnO NPs. The absorption spectra analysis exhibited that the optical energy band gap (Eg) for the ZnO NPs increased with increasing of UP from 2.84 eV to 3.13 eV. Two groups (I and II) of dye sensitized solar cell (DSSCs) device based on the synthesized ZnO NPs were fabricated. In group I, 0.32 mM Eosin B (EB) used as photosensitizer for the samples U1, U2, U3 and U4, which showed that the overall conversion efficiency (η) increased from 0.09% to 0.13%, under a light intensity of 100 mW/cm2 due to the increasing of UP. Group II, different photosensitizer EB, Eosin Y (EY) and Rhodamine B (RB) used to sensitized the U4, where the EY exhibited the best all of them. The conversion efficiency presented a significant improvement from 0.13 to 1.26%. The combustion method can be considered as a promising method to produce good photoanode semiconductors such ZnO subsequently increase the efficiency of the solar cellThis research activity carried out under the financial support by the Palestinian German Joint Research Project PALGER2015-34-012 and partially by the PHC Al Maqdisi grant No. 37038WF. Referencesاستخدام جسيمات اكسيد الزنك النانوية كقطب سالب للخلايا الشمسي

Perovskite solar cells free of hole transport layer

In this work, easy and simple structured perovskite solar cells (PSCs) are designed and characterized. Our effort was to reduce the cost of the fabrication of such PSC devices, first by using an inexpensive starting precursor (aqueous methylamine solution) for the perovskite materials and second by design in a PSC structure free of the expensive hole transport layer (HTL). The CH3NH3PbI3 perovskite sols were deposited onto a conductive FTO glass using the spin coating technique followed by heating at 100 °C for 10 min. The structure of the films was characterized by X-ray diffraction (XRD) and their optical properties by UV–VIS spectrophotometry and photoluminescence (PL). The obtained phase confirmed the formation of a tetragonal perovskite structure. Two different solvents have been used, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The effect of the type and the concentration of the used solvent DMF and DMSO on the performance of the solar cells have been investigated. It was found that a 40% concentration of the perovskite material resulted in the optimum film thickness that gives the best photoelectric performance. The DMF-based PSC assembled solar cell exhibited the best performance with an open circuit voltage of 750 mV, a photocurrent density of 12.5 mA/cm2, and an overall photon to electric conversion efficiency of 5.7%; all these results are higher than those of cells made with DMSO.This work was supported financially partially by the PHC Al Maqdisi Grant No. 37038WF and the Palestinian German Joint Research Project PALGER2015-34-012. The authors would like to thank Mr. Ahmad Ashour for his assistance in UV–VIS measurements.In this work, easy and simple structured perovskite solar cells (PSCs) are designed and characterized. Our effort was to reduce the cost of the fabrication of such PSC devices, first by using an inexpensive starting precursor (aqueous methylamine solution) for the perovskite materials and second by design in a PSC structure free of the expensive hole transport layer (HTL). The CH3NH3PbI3 perovskite sols were deposited onto a conductive FTO glass using the spin coating technique followed by heating at 100 °C for 10 min. The structure of the films was characterized by X-ray diffraction (XRD) and their optical properties by UV–VIS spectrophotometry and photoluminescence (PL). The obtained phase confirmed the formation of a tetragonal perovskite structure. Two different solvents have been used, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The effect of the type and the concentration of the used solvent DMF and DMSO on the performance of the solar cells have been investigated. It was found that a 40% concentration of the perovskite material resulted in the optimum film thickness that gives the best photoelectric performance. The DMF-based PSC assembled solar cell exhibited the best performance with an open circuit voltage of 750 mV, a photocurrent density of 12.5 mA/cm2, and an overall photon to electric conversion efficiency of 5.7%; all these results are higher than those of cells made with DMSO