Electrical and optical properties of spin-coated SnO2 nanofilms

Abstract

SnO 2 nanocrystalline thin films have been deposited on oxidized silicon substrates by spin-coating from a precursor solution, followed by slow thermal annealing in oxygen atmosphere at different temperatures (500 to 900°C). The precursor solution consisted of 1.0 to 2.0 M SnCl 4 ·5H 2 O in isopropanol. It was shown that the concentration of the precursor solution, annealing temperature and heating rate had a significant effect on the structural, optical and electrical properties of the studied thin films. The topography of SnO 2 thin films was examined by scanning electron microscopy (SEM). Furthermore, as-deposited films were characterized by X-ray diffraction (XRD), UV-Vis and impedance spectroscopy.

Surface properties of SnO2 nanolayers prepared by spin-coating and thermal oxidation

“…As shown in table 1, the XPS experiments confirm that the surface of all our SCTO SnO 2 nanolayers is slightly nonstoichiometric, with an evident domination of tin dioxide which is crucial, and we have to underline at this point, is that the above conclusion cannot be understood as contradictory to information obtained from our previous XRD experiments [19]. The XRD results presented in [19] clearly indicated only the presence of SnO 2 formed in the SCTO SnO 2 nanolayers under study.…”

“…As shown in table 1, the XPS experiments confirm that the surface of all our SCTO SnO 2 nanolayers is slightly nonstoichiometric, with an evident domination of tin dioxide which is crucial, and we have to underline at this point, is that the above conclusion cannot be understood as contradictory to information obtained from our previous XRD experiments [19]. The XRD results presented in [19] clearly indicated only the presence of SnO 2 formed in the SCTO SnO 2 nanolayers under study. However, in contrast to the XRD method, one has to bear in mind that XPS is primarily a surface sensitive technique, especially when using the x-ray photon energy (1486.6 eV), able to recognize the surface chemical species in the very first few layers in depth only up to 10 nm.…”

“…What is the most important, as our SEM studies confirmed, SCTO SnO 2 nanolayers after post-oxidation at temperatures higher than 500 °C exhibit a well separated grain structure. In our previous paper [19], undertaking XRD phase analysis of SCTO SnO 2 nanolayers, it was shown that the samples demonstrated an irregular crystalline structure on the (110) facets and the Debye-Scherrer formula showed that the average sizes of the interconnected individual grain-type SnO 2 crystallites in the SCTO SnO 2 nanolayers after post-oxidation at temperatures of 500 and 700 °C were 5.1 and 6.7 nm, respectively.…”

“…The thickness of our SCTO SnO 2 was estimated to be about ∼200 nm, and does not significantly evolve during above mentioned post-oxidation procedure. Other experimental details can be found in [19].…”

Evolved photovoltaic performance of MAPbI3 and FAPbI3-based perovskite solar cells in low-temperatures

“…Recently, there has been a growing exploration of perovskite performance in low-temperature conditions, unveiling its potential for development. In a study by Chen et al, conventional n-i-p planar solar cell employing (FA,MA,Cs)Pb(I,Br) 3 (FAMACs)-based perovskite materials achieved a remarkable 25.2% efficiency at 220 K, showing an increasing PCE trend from 300 to 220 K, followed by a decline as temperature further decreased to 130 K [8] . Similar trends were observed in the V OC and hysteresis index, but no change was noted in Jsc density across the temperature range.…”