engleski

Impedance spectroscopy for Solar Cells: Electrical Properties of Nanostructured Electrodes Based on Aluminium Doped Zincite

Energy requirements are higher by the day, and year, which is very challenging to ensure. In order to mitigate harmful environmental impact, renewable energy sources are recently attracting more attention. Nowadays, the solar energy is considered the most useful environmentally friendly energy source. Many photovoltaic systems are being developed for utilisation of endless solar energy resources. This study offers a comparison of aluminium-doped zincite prepared by the magnetron sputtering method, using different strengths of current for aluminium sputtering while for ZnO held constant. Derived transparent electrodes are structurally characterized by photoluminescence (PL) and Raman spectroscopies, as well as scanning electron (SEM) and atomic force (AFM) microscopies. The electrical properties of samples are studied by solid-state impedance spectroscopy (IS). For connecting electrical contacts with impedance analyser, platinum wires are used. From the experimental study of electrical properties, complex sheet electrical conductivity is calculated, and direct current sheet conductivity, is determined from the low-frequency plateau in conductivity spectra. More importantly, the electrical properties are studied employing temperature-resolved impedance spectroscopy (IS), see Figure 2. IS characterization attempted to clarify the extent of influence of the preparation process, along with the nano-structuring of the oxide layer and achieving thin-films, on the electrical transport properties in this type of material. All studied thin-film samples decrease values of sheet resistance and increase DC sheet electrical conductivities when shifted to higher temperatures. Observed temperature-dependent behaviour suggests semiconducting nature of the prepared films. Calculations enabled insights into the dynamics of electrical transport, which is further correlated with structural characteristics of obtained thin- films. The possibility to further tune the applicability of these materials is discussed. Consequently, the results show that electrical conductivity is heavily affected by aluminium content.

Zincite ; Impedance spectroscopy ; solar cells ; thin-films

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