Optimization of plasmonic Al/TiO₂ thin film characteristics via scanning pulsed fiber laser deposition

Abstract

The deposition method of perovskite solar cell layers significantly impacts device functionality and the achievement of industrial goals. Aluminum (Al) nanoparticles with rutile titanium oxide (TiO₂) nanoparticle thin films are fabricated on Fluorine Tin Oxide (FTO) glass substrates by nanosecond pulsed fiber laser deposition (PLD) to be used as a plasmonic electron transport layer (ETL) in perovskite solar cell (PSC). The effect of various pulsed fiber laser parameters on the structural, optical, and surface morphology on Al/TiO₂ films is extensively examined utilizing a variety of measurement techniques; X-ray diffraction (XRD), Ultraviolet–visible (UV–Vis) spectroscopy, Field emission scanning electron microscopy (FE-SEM) and Atomic Force microscope (AFM). XRD demonstrates that Al/TiO₂ thin films has a mixed phase (anatase/rutile). The minimum average crystallite size of Al/TiO₂ thin films deposited at (2 W - 40 kHz) is (19.8 nm). The absorption spectrum of the deposited Al/TiO₂ thin film at (10 W - 20 kHz) shows a red-shifted absorption peak at 316 nm, while 307 nm is detected at (2 W - 20 kHz). As the pulse repetition rate rise (40, 60 kHz), a new absorption peak in the UV spectral region at 341 nm was observed. FESEM images demonstrate the nanoparticles’ uniformity and polycrystalline nature. The shape of nanoparticles becomes more uniform and smaller size when the power increases. The minimum power required to get a uniform film is 0.8 W nm with suitable thickness of 398.8 obtained by fitting the thickness values curve of Al/TiO₂ thin films. The elemental analysis examined by the EDX spectrum of Al/TiO₂ thin films consists of oxygen, aluminum, and titanium. AFM images reveal a granular microstructure, and a flat texture, with the lowest surface roughness. The obtained results from the current study indicate that the structural, optical, and morphological properties can be controlled by varying the fiber laser parameters to deposit an efficient plasmonic Al/TiO₂ thin films could be used as an electron transport layer which open new trends to improve the performance of perovskite solar cell.