Prospect of SnO2 Electron Transport Layer Deposited by Ultrasonic Spraying

Abstract

The SnO2 electron transport layer (ETL) has been characterized as being excellent in optical and electrical properties, ensuring its indispensable role in perovskite solar cells (PSCs). In this work, SnO2 films were prepared using two approaches, namely, the ultrasonic spraying method and the traditional spin-coating, where the different properties in optical and electrical performance of SnO2 films from two methods were analyzed by UV–Vis, XRD, AFM, and XPS. Results indicate that the optical band gaps of the sprayed and the spin-coated film are 3.83 eV and 3.77 eV, respectively. The sprayed SnO2 film has relatively low surface roughness according to the AFM. XPS spectra show that the sprayed SnO2 film has a higher proportion of Sn2+ and thus corresponds to higher carrier concentration than spin-coated one. Hall effect measurement demonstrates that the carrier concentration of the sprayed film is 1.0 × 1014 cm−3, which is slightly higher than that of the spin-coated film. In addition, the best PCSs efficiencies prepared by sprayed and spin-coated SnO2 films are 18.3% and 17.5%, respectively. This work suggests that the ultrasonic spraying method has greater development potential in the field of flexible perovskite cells due to its feasibility of large-area deposition.

Robust electron transport layers of SnO2 for efficient perovskite solar cells: recent advances and perspectives

“…Previous research has demonstrated that spraying SnO 2 thin films increases light transmittance and broadens the optical band gap, while also improving film quality. 57 The sprayed SnO 2 film, for instance, had a greater fraction of Sn 2+ and consequently a higher carrier concentration compared to the spin-coated SnO 2 film, according to XPS spectroscopic examination. Guan et al created a SnO 2 ETL with a flat surface, no pinholes, and high electron transfer efficiency using an ultrasonic spraying technique (Fig.…”

Review on Surface Modification of SnO2 Electron Transport Layer for High-Efficiency Perovskite Solar Cells

“…Unexpectedly, the AFM on SnO 2 and Ni:SnO 2 perovskite films attained roughness values of 31.8 and 23.25 nm, respectively (Figure 4e,f), indicating that the SnO 2 -modified perovskite was smoother, as shown in Figure 4g,h. In addition, a 20 mm thick SnO 2 film was prepared using spin coating and spraying on the FTO substrate, respectively, to evaluate the variations in surface morphology with the two approaches [72]. The film fabricated by applying spin coating yielded an RMS roughness of 14.1 nm and maximum variation of 92.2 nm, whereas that produced by employing spraying yielded an RMS roughness of 5.79 nm and maximum variation of 41.2 nm.…”

Atomic layer deposition of SnO2 using hydrogen peroxide improves the efficiency and stability of perovskite solar cells

“…Among the studied ETLs, the wide bandgap SnO 2 formed at low temperatures is widely used for ETL because of high carrier mobility, lowtemperature processibility, and photo-inactive nature under UV illumination. [12][13][14][15] Various coating methods have been reported to fabricate SnO 2 thin films including chemical bath deposition, 16 spray-pyrolysis, 17 and atomic layer deposition (ALD). [18][19][20][21] ALD is one of the beneficial techniques for conformal and uniform coating compared to other methods.…”