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    Öğe
    Improved performance of CdS powder-based hybrid solar cells through surface modification
    (2021) Ünverdi, Ahmet; Yılmaz, Salih; Tomakin, Murat; Polat, İsmail; Bacaksız, Emın
    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.
  • [ X ]
    Öğe
    Role of Mg doping in the structural, optical, and electrical characteristics of ZnO-based DSSCs
    (2017) Polat, İsmail; Yılmaz, Salih; Tomakin, Murat; Bacaksız, Emin
    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.