Investigation of Optical, Morphological and Structural Properties of Solar Absorber CH3NH3PbI3-xClx Perovskite Structure Produced by Ultrasonic Spray Pyrolysis Method

Abstract

In this study, CH3NH3PbI3-xClx perovskite thin films were deposited on glass substrates by the ultrasonic spray pyrolysis method. The effect of substrate temperature on the structural, morphological and optical properties of perovskite films was investigated using an X-ray diffraction (XRD) device, scanning electron microscope (SEM), atomic force microscope (AFM), and Uv-Vis spectrophotometer. When the X-ray diffraction spectra were observed, it was determined that all films were formed in the tetragonal perovskite lattice structure, but it was observed that different undesirable crystal structures were formed in thin films with 75 °C and 100 °C substrate temperatures. Although no post-annealing process was applied to the films, it was determined that the films coated at 125 ° C substrate temperature were in the form of pure perovskite crystals, which are exactly compatible with the literature. The crystal sizes of thin films were determined by using XRD spectrum data and Debye-Scherrer formula. The highest crystal size was obtained as 743 Å for the thin film deposited at a substrate temperature of 125 °C. When the SEM images were examined, it was determined that the film surfaces were homogeneously coated at only 125 °C substrate temperature and that there were no voids between the crystal particles. The surface roughness of the films was examined by atomic force microscopy system, and the smoothest surface roughness was obtained in the thin film deposited at 125 °C substrate temperature with 41.32 nm. Optical absorption studies were carried out by using a Uv-Vis spectrophotometer operated at room temperature. It was observed that as the substrate temperature applied while coating the films increased, the forbidden bandgap of the film increased from 1.20 eV to 1.56 eV, which is also compatible with the theoretical analysis.

Keywords

• Ultrasonic spray pyrolysis
• Perovskite
• Substrate temperature

Ultrasonik Sprey Piroliz Yöntemi ile Üretilen Güneş Soğurucu CH3NH3PbI3-xClx Perovskit Yapısının Optik, Morfolojik ve Yapısal Özelliklerinin İncelenmesi

Abstract

Bu çalışmada ultrasonik sprey piroliz yöntemi ile cam alttaşlar üzerine CH3NH3PbI3-xClx perovskit ince filmler kaplanmıştır. Alttaş sıcaklığının perovskit filmlerin yapısal, morfolojik ve optik özellikleri üzerine etkisi, X-ışını kırınım (XRD) cihazı, taramalı elektron mikroskobu (SEM), atomik kuvvet mikroskobu (AFM) ve Uv-Vis spektrofotometresi kullanılarak araştırılmıştır. XRD spektrumları incelendiğinde, tüm filmlerin tetragonal perovskit örgü yapısında olduğu ancak 75 °C ve 100 °C alttaş sıcaklığı uygulanan ince filmlerde farklı kristal yapılara ait fazladan piklerinde olduğu görülmüştür. Filmlere sonradan herhangi bir tavlama işlemi uygulanmadığı halde, 125 °C alttaş sıcaklığında kaplanan filmlerin literatür ile birebir uyumlu saf perovskit kristali formunda olduğu tespit edilmiştir. XRD spektrum verileri ve Debye-Scherrer formülü kullanılarak ince filmlerin kristal boyutları belirlenmiştir. En yüksek kristal boyutu 743 Å ile 125 °C alttaş sıcaklığında kaplanan filmlerde elde edilmiştir. SEM görüntüleri incelendiğinde film yüzeylerinin sadece 125 °C alttaş sıcaklığında homojen kaplandığı ve kristal tanecikler arasında boşlukların oluşmadığı saptanmıştır. Filmlerin yüzey pürüzlülüğü atomik kuvvet mikroskobu ile incelenmiş, en düşük yüzey pürüzlülüğü 41.32 nm ile 125 °C alttaş sıcaklığına sahip olan ince filmde elde edilmiştir. Optik soğurma ölçümleri, oda sıcaklığında çalıştırılan Uv-Vis spektrofotometre kullanılarak gerçekleştirilmiştir. Filmler kaplanırken uygulanan alttaş sıcaklığı artıkça filme ait yasak bant aralığının 1.20’ eV tan teorik analizler ile de uyuşan 1.56 eV’ a çıktığı görülmüştür.

Keywords

• Ultrasonik sprey piroliz
• Perovskit
• Alttaş sıcaklığı

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