Effect of Oxygen Vacancy on the Crystallinity and Optical Band Gap in Tin Oxide Thin Film

Rajesh Dangi, Bijaya Basnet, Manoj Pandey, Sandip Bhusal, Biplab Budhathoki, Kshama Parajuli (), Santosh K. Tiwari () and Bhim P. Kafle ()
Additional contact information
Rajesh Dangi: Central Department of Chemistry, Tribhuvan University, Kirtipur 44618, Kathmandu, Nepal
Bijaya Basnet: Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA
Manoj Pandey: Department of Physics, School of Science, Kathmandu University, Dhulikhel 45210, Kavre, Nepal
Sandip Bhusal: Central Department of Chemistry, Tribhuvan University, Kirtipur 44618, Kathmandu, Nepal
Biplab Budhathoki: Central Department of Chemistry, Tribhuvan University, Kirtipur 44618, Kathmandu, Nepal
Kshama Parajuli: Central Department of Chemistry, Tribhuvan University, Kirtipur 44618, Kathmandu, Nepal
Santosh K. Tiwari: Department of Chemistry, NMAM Institute of Technology, Nitte (Deemed to be University), Nitte 547110, Karnataka, India
Bhim P. Kafle: Department of Chemical Science & Engineering, School of Engineering, Kathmandu University, Dhulikhel 45210, Kavre, Nepal

Energies, 2023, vol. 16, issue 6, 1-18

Abstract: Herein, we have prepared tin oxide (SnO 2 ) nanoparticles (NPs), through a co-precipitation method, using SnCl 2 · 2H 2 O dissolved in distilled water (DW) as a precursor. Then, the prepared NPs were heat treated in a muffle furnace, as a function of temperature, under an open atmosphere. The prepared SnO 2 NPs were then re-dispersed in DW, followed by spray casting on a glass substrate, for preparing SnO 2 thin films. The average thickness of the fabricated SnO 2 thin films was 2.76 µm. We demonstrated a very clear variation in the structural, compositional, and morphological features of the different films (in particular, variation of the density of oxygen vacancies), which altered their electrical and optical properties. Raising the calcination temperature of the SnO 2 thin films, from 250 °C to 650 °C, led to a monotonic reduction in the crystallite size, from 10.4 nm to 6.7 nm, and a decrease in the O/Sn ratio, from 5.60 to 4.79. A 14.5% decrease in the O/Sn ratio resulted in a decrease in the crystallite size by 3.7 nm (i.e., a 35.3% decrease in the NP size), and a decrease in the band gap of 0.11 eV. The lowering of the band gap, along with an increase in the oxygen vacancies in the films, accords well with previous studies. Besides, as the calcination temperature was raised, the refractive index and absorption coefficient values were also found to notably increase. Very interestingly, by simply altering the calcination temperature, we were able to produce SnO 2 thin films with optical band gaps nearly equal to the fundamental band gap (2.96 eV), even though many earlier experimental studies had reported considerably greater values (3.36–4.24 eV). SnO 2 thin films with lower oxygen vacancies exhibited relatively higher band gaps, which is likely to be favorable for the desired electron transport layer in perovskite solar cells.

Keywords: nanoparticles; thin film; calcination; oxygen vacancies; optical properties; crystallite size (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/16/6/2653/pdf (application/pdf)
https://www.mdpi.com/1996-1073/16/6/2653/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:16:y:2023:i:6:p:2653-:d:1094674

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().