Role of Mg doping in the structural, optical, and electrical characteristics of ZnO-based DSSCs

ZnO- and Mg-doped ZnO samples are prepared by spray pyrolysis on conducting glass substrates to fabricate ZnO-based dye-sensitized solar cells (DSSCs). In uences of Mg-doping content on the power conversion efficiencies of ZnO-based DSSCs are investigated. X-ray diffraction results show that all the samples exhibit a hexagonal wurtzite structure. Scanning electron microscopy data indicate that the ZnO sample has uniform rods with 1 ? m diameter. With respect to ZnO, the band gap value of 4 at.% Mg-doped ZnO samples improves to the value of 3.27 eV and a further increase in Mg level up to 6 at.% gives rise to a decline in the band gap value of 3.22 eV. Photoluminescence measurements illustrate that intensities of the ultraviolet peak and a red luminescence peak take their maximum values for 4 at.% Mg doping. From solar cell performance measurements, the best power conversion efficiency of 0.08% is obtained for the doping amount of 4 at.% Mg

Yüzey modifikasyonu yardımıyla CdS toz bazlı hibrit güneş pillerinde performans artışı

The effects of surface modification of CdS through organic Eosin-Y, indoline D205, and Ru-based complex N719 and N3 dyes on CdS-based hybrid solar cells were studied. Chemical bath deposition (CBD) and doctor blade methods were in turn employed to fabricate the CdS specimens on Indium-Tin Oxide (ITO) covered glass substrates. P3HT material with and without dye coatings was covered through a spin-coater on the surface of CdS specimens. Ag paste was then deposited on the surface of P3HT to obtain hybrid solar cells. Structural analysis indicated that CdS powders showed a cubic growth with the preferred orientation of (111). Morphological analysis demonstrated that CdS powders exhibited hierarchical morphology and the morphology turned to granular structure with some porosity upon deposition of both N3 dye and P3HT layers. Absorption plots indicated that Eosin-Y dye loading led to a rise in the absorbance values of CdS specimens. After dye loading, photoluminescence data of CdS-based heterostructure illustrated a decrement in the luminescence intensity, implying that effective exciton dissociation was obtained. Current density-voltage (J-V) characteristics of the hybrid solar cells depicted that the best overall efficiency was observed for Eosin-Y-modified cell as 0.135%. This proved that surface modification by Eosin-Y dye led to a better interfacial contact between CdS and P3HT bilayer due to the enhancement in the charge separation.CdS-tabanlı hibrit güneş pillerinde, CdS'nin yüzey modifikasyon etkileri organik Eosin-Y, indolin D205 ve Ru bazlı N719 ve N3 boyaları vasıtasıyla incelendi. CdS örneklerini İndiyum-Kalay Oksit (ITO) kaplı cam altlıklar üzerinde büyütmek için, sırasıyla kimyasal banyo çökeltme (CBD) ve doktor bıçak yöntemleri kullanıldı. Boya kaplamaları olan ve olmayan CdS örneklerinin yüzeyine P3HT materyali, spin kaplama (spin-coater) cihazı yardımıyla kaplandı. Devamında Ag pasta, hibrit güneş pillerini tamamlamak için P3HT yüzeyine çökeltildi. Yapısal analiz, CdS tozlarının kübik yapıda ve (111) tercihli yönelime sahip olduğunu gösterdi. Morfolojik analiz, CdS tozlarının hiyerarşik morfolojide olduğunu ve morfolojinin hem N3 boyası hem de P3HT tabakasının çökeltilmesiyle birlikte taneli ve gözenekli yapıya döndüğünü gösterdi. Soğurma (absorbsiyon) grafikleri, Eosin-Y boya kaplamasının CdS örneklerinin soğurma değerinde bir artışa yol açtığını gösterdi. Boya kaplamasının, CdS tabanlı heteroyapının fotolüminesans şiddetinde azalma oluşturması, etkin bir eksiton ayrışması elde edildiğini ortaya koymaktadır. Hibrit güneş pillerinin akım yoğunluğu-voltaj (J-V) karakteristiklerinden, Eosin-Y modifikasyonlu güneş pilinin veriminin % 0,135 olarak en yüksek değerde olduğu tespit edildi. Bu durum, Eosin-Y boyası ile yapılan yüzey modifikasyonunun, yük ayrışmasında oluşturduğu iyileşmeden dolayı, CdS ve P3HT ikili yapısının arasında daha iyi bir ara yüzey teması sağladığını ispatlamaktadır

The investigation of stability of n-CdS/p-Cu2S solar cells prepared by cold substrate method

In this study, two different n-CdS/p-Cu2S solar cells were prepared by evaporating Cu at different substrate temperatures (200 K and 300 K) by vacuum evaporation method on a single crystal CdS semiconductor. Field emission scanning electron microscope images showed that the Cu layer obtained at a temperature of 200 K was composed of nanoparticles in accordance with the soliton growth mechanism. Cu film thickness was determined as 395 0.76 nm at 300 K substrate temperature and 187 0.45 nm at 200 K substrate temperature. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the solar cells were examined for 12 weeks in dark and light environments. Open-circuit voltage (V-oc), short-circuit current (I-sc), maximum power (P-max), filling factor and efficiency (eta) were calculated from I-V measurements. For the prepared solar cells, the highest efficiency value was obtained in the 7th week (eta= 0.1360) at 200 K substrate temperature, while it was obtained in the 5th week (eta = 0.0384) at 300 K substrate temperature. From C-V measurements, donor density (N-d) and barrier potential (V-bi) were calculated. The solar cell produced at 200 K substrate temperature has higher donor density (1st week 2.99 x 10(16) cm(-3)) and barrier potential values (12th week 0.411 V). At the end of the 12-week period, the deterioration rate of solar cells created at 200 K and 300 K substrate temperatures was 51% and 94%, respectively

The investigation of magnetic levitation performances of single grain YBCO at different temperatures

Celik, Sukru/0000-0002-6918-7569; GUNER, SAIT BARIS/0000-0001-7487-4817WOS: 000397994700032The temperature dependence of the magnetic levitation force has been investigated for single-grain YBCO bulk sample, 20 mm in diameter with a thickness of 8 mm, fabricated by top-seeded melt growth (TSMG) method using Nd123 seeded. the superconducting properties of the single grain YBCO bulk are studied by VSM (Vibrating Sample Magnetometer), the microstructures and the phase constituents of those that are seen by SEM (Scanning Electron Microscope) and XRD (X-ray Diffraction). the measurements of superconducting properties indicated that magnetic levitation forces of the sample were found 11.23, 10.81, 10.34, 9.23 and 7.02 N at the temperatures of 37, 47, 57, 67 and 77, respectively, and the values of the onset critical temperature (Tc) and the zero-field critical current density (Jc) are 89.3 K and 5.6 x 10(4) A/cm(2) at 77 K, respectively. This research is intended to help for the large scale superconductor levitation performances at different temperatures. (C) 2017 Elsevier B. V. All rights reserved.Recep Tayyip Erdogan University Scientific Research Projects Coordination Department [2014.102.01.05]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110T622]All the authors would like to thank Dr. Hari Babu Nadendla (at Brunel University, London, UK) for the sample preparation method developed by him, Dr. Yunhua Shi (at Cambridge University, Cambridge, UK) and Kenta Nakazato (at Shibaura Institute of Technology, Tokyo, Japan) for his support and encouragement. This research was supported by the Recep Tayyip Erdogan University Scientific Research Projects Coordination Department (Project Number: 2014.102.01.05). All the magnetic levitation force measurements were performed in the MLFMS designed by the project of TUBITAK (Project Number: 110T622) and whose patent application number is 2013/13638 for the Turkish Patent Institute (TPE)

Cold substrate method to prepare plasmonic Ag nanoparticle: deposition, characterization, application in solar cell

Tomakin, Murat/0000-0003-1887-848XWOS: 000518475700001In this study, the surface plasmon effects of the Ag nanoparticle were investigated depending on the substrate temperature and coating time. Deposition procedure for the Ag coating was the vacuum deposition at low substrate temperature (< 300 K) instead of the commonly used the vacuum deposition at high substrate temperatures. the Ag thin films were deposited on n-type Si, glass and solar cell with safety glass substrates. the structural and optical characteristics of the Ag thin films prepared on Si and glass substrates were investigated. the Ag thin films had a polycrystalline structure with cubic phase. the (111) preferred orientation for 300 K substrate temperature was changed to (200) after 200 K substrate temperature. Homogeneous nano-sized Ag particles on Si were obtained at the 150-200 K temperature range. Optical measurements were performed for the Ag thin films prepared on glass substrates. According to reflectance measurements, plasmon resonance effect of the Ag nanoparticles was observed around 435-540 nm. the Ag nanoparticles prepared on solar cell at low substrate temperature increased the solar cell efficiency for all coating time because the nanoparticle size and shape were not changed significantly with the coating time. However, the Ag thin films prepared at high substrate temperature decreased device efficiency with the increasing coating time

A atudy on hydrothermal grown CdS nanospheres: effects of Cd/S molar ratio

The study reports the influences of altering of Cd/S molar ratio on some physical properties of hydrothermal grown CdS nanospheres. Cd/S molar ratios were chosen as 1:0.5, 1:1, 1:2, 1:3 and 1:4 in the stock solution. X-ray diffraction (XRD) data showed the occurrence of nano-amorphous CdS structure. Scanning electron microscopy (SEM) conclusions illustrated that increasing Cd/S molar ratio up to 1:3 caused a growth in the sphere size whereas further rising of Cd/S molar ratio led to smaller sphere size. The presence of Cd and S atoms in CdS structure was approved by Energy dispersive x-ray spectroscopy (EDS) analysis. Optimum transparency was found by Cd/S molar ratio of 1:3. Band gap scores of CdS nanospheres were determined to be above 2.60 eV that was bigger than bulk CdS (2.42 eV) because of quantum confinement effect. Photoluminescence (PL) results showed that a gradual decrease in each peak was attained upon increasing Cd/S molar ratio, which could be due to the formation non-radiative recombination phenomenon. Electrical data demonstrated that CdS nanosphere having Cd/S molar ratio of 1:1 exhibited the best carrier density (1.48X1015cm-3) and resistivity (1.27X103 ?.cm) values. Thus, it can be deduced that Cd/S molar ratio of 1:3 was obtained to be optimum one since it possesses both bigger sphere size and better transparency, facilitating the effective use of CdS nanospheres in the solar cells

Comparison of the impact of different chlorination treatments to ZnS and CdS thin films

In this study, the effect of ZnCl2 and CdCl2 treatments on the structural, optical and electrical properties of ZnS and CdS thin films grown by chemical bath deposition method was examined. Employing CdCl2 or ZnCl2 treatment to CdS caused a change from cubic to hexagonal structure. After treating ZnS with CdCl2, ZnS phase disappeared and a highly crystalline hexagonal CdS phase formed. CdCl2 treatment on CdS showed an improving effect on surface morphology, but ZnCl2 led to an unfavorable effect. CdCl2 treatment to ZnS was transformed it into a fused structure in which individual grains were disappeared. Treatment of ZnCl2 to ZnS and CdCl2 to CdS induced a slight increase in the amount of Zn and Cd, respectively. However, processing of CdCl2 to ZnS (or ZnCl2 to CdS) resulted in significant quantity of Cd (or Zn) elements in the samples. The transmittance of CdS decreased with CdCl2 and ZnCl2 treatments. However, the highest transmittance in ZnS thin films was achieved after ZnCl2 treatment. According to PL spectra, different emission types increased partially in CdS/CdCl2, but decreased in CdS/ZnCl2. After applying ZnCl2 treatment to ZnS, the emission type appears similar to the as deposited sample, while CdCl2 treatment caused the emission type to change. Electrical measurements showed that the resistivity and carrier concentrations of the samples were in the order of 10(3) Omega cm and 10(13) cm(-3), respectively. The carrier concentrations of the CdS/ZnCl2 and ZnS/CdCl2 sample increased slightly compared the as deposited samples

Impact of in/ex situ annealing and reaction temperature on structural, optical and electrical properties of SnS thin films

In this work, SnS thin films were prepared by in situ and ex situ annealing process of precursor films deposited by RF (Radio Frequency) magnetron sputtering employing binary SnS target. In situ annealing treatment was performed in sputtering chamber and ex situ annealing treatment was performed using RTP (Rapid Thermal Processing) system under Ar+H-2 mix gas employing 225, 300 and 375 degrees C as reaction temperatures in order to find out the best fabrication parameters of SnS thin film since it has been used as an absorber layer in the cell structure. The EDX (Energy Dispersive X-ray Spectroscopy) measurements showed that precursor and reacted films have almost stoichiometric composition except for in situ annealed sample at 375 degrees C. XRD (X-ray Diffraction) patterns of all samples revealed orthorhombic SnS phase regardless of annealing route and temperature. In addition to SnS phase, formation of SnS2 phase was observed in in situ annealed SnS samples at 225 and 300 degrees C. Moreover, in situ annealed samples displayed larger crystallite size and lower micro strain compared to ex situ annealed samples. Raman spectra of the samples confirmed formation of orthorhombic SnS phase and it was also seen that crystalline quality gave rise to shift in position of Raman bands for some samples. Only a SEM (Scanning Electron Microscopy) image of in situ annealed sample at 375 degrees C displayed distinct surface morphology. Optical band gap values of the samples showed variation between 1.35 and 1.66 eV. Electrical characterization of the films showed that resistivity values changed from 3.34x10(3) to 2.28x10(4) Omega-cm and carrier concentration values changed from 1.34x10(14) to 1.05x10(15) cm(-3). It was seen that in situ annealing at 375 degrees C exhibited more promising results for potential SnS based photovoltaic applications. (C) 2021 Elsevier B.V. All rights reserved

Effects of Na doping on CdS thin films and n-CdS/p-Si solar cells via chemical bath deposition method

WOS: 000413298900004Un-doped and Na doped CdS thin films were deposited by chemical bath deposition method. the effects of Na doping on structural, optical and electrical properties of CdS thin films and n-CdS/p-Si heterojunction were investigated. Crystal structure of all CdS thin films was cubic with (111) preferred direction. High Na doping detoriated crystal structure and amorphous structure obtained for 3% Na doping. the grain size of thin films was decreased from 6.5 nm to 4.8 nm and surface homogeneity increased with Na doping. All samples had high band gap for CdS (2.42 eV) due to quantum size effect and band gap of the samples was increased 3.65 eV to 3.84 eV as a function of Na content. Na doped CdS samples had higher resistivity and carrier concentration than that of un-doped CdS. Ideality factors of Na doped n-CdS/p-Si heterojunctions were greater than unity due to nanostructered CdS, which indicates that the diode exhibits a nonideal behavior. It was determined that photovoltaic behavior of n-CdS/p-Si prepared with high Na doped CdS dependent on different semiconductor structure (such as depend on function of Na2SiO3 phase) occurred interface of CdS and Si.Grants-in-Aid for Scientific ResearchMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of ScienceGrants-in-Aid for Scientific Research (KAKENHI) [26289186] Funding Source: KAKE

Fabrication of CdS nanospheres-based hybrid solar cells having increased efficiency

The impact of surface modification through diverse dyes (Eosin-Y, D205, N719 and N3) on structural, morphological, optical, and electrical properties of CdS/P3HT hybrid solar cells is studied. X-ray diffraction (XRD) pattern shows that CdS nanospheres have a hexagonal structure with a preferential orientation of (002) with respect to indium tin oxide (ITO) coated glass slide. Scanning electron microscopy (SEM) results indicate that compact and dense spherical morphologies of CdS occurred, and the P3HT layer also consisted of small spherical grains. The bandgap of CdS is found to be 2.52 eV according to Tauc's plot analysis. Absorption spectra demonstrate that interfacial modification via each dye leads to an increase in the absorption in the wavelength range of 300-1000 nm. Photoluminescence (PL) data prove that surface modification of CdS nanospheres with diverse dyes causes a decrease in the spectral intensity of PL curve, implying that efficient exciton separation is taking place upon dye loadings. Fabricated devices with and without modification show photovoltaic effects that can be seen from current density-voltage (J-V) curves obviously, and the highest power conversion efficiency (PCE) is obtained as 0.881% for N719-modified (ITO/CdS/N719/P3HT/Ag) device (almost 70-fold of pristine one) with a short-circuit current density (J(sc)) of 2.878mA/cm(2) and open-circuit voltage (V-oc) of 0.92V, respectively. This enhancement can be attributed to a better surface area between CdS and P3HT after dye modification