Cu2O thin films deposited by spray pyrolysis using diethanolamine and L-ascorbic acid as reducing agents

M. Ugalde-Reygadas; Valeria D. Moreno-Regino; Carlos G. Torres-Castanedo; Michael J. Bedzyk; Rebeca Castanedo-Pérez; Gerardo Torres-Delgado

doi:10.1016/j.mtcomm.2022.103999

Cu₂O thin films deposited by spray pyrolysis using diethanolamine and L-ascorbic acid as reducing agents

M. Ugalde-Reygadas, Valeria D. Moreno-Regino, Carlos G. Torres-Castanedo, Michael J. Bedzyk, Rebeca Castanedo-Pérez^*, Gerardo Torres-Delgado

^*Corresponding author for this work

Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

7 Scopus citations

Abstract

Cu₂O thin films are of great interest due to their diverse applications. Spray pyrolysis is a low-cost and straightforward technique among the different methods used to deposit them. Precursor solutions using D-glucose as reducing agent and copper acetate have mainly been used. However, the D-glucose's remaining subproduct can detriment the films' properties and use in devices. In this work, precursor solutions using diethanolamine (DEA) or L-ascorbic acid (AA) as reducing agents to deposit Cu₂O thin films are used for the first time. The effect on the structural, morphological, electrical, and optical properties of Cu₂O thin films is shown for 0.25 M of DEA and 0.1 M of AA, which were the optimal molar concentrations to obtain homogeneous solutions, with 0.04 M of copper nitrate. The deposition temperature (T_d) determines the formation of Cu₂O single phase. XRD analysis reveals films only constituted by Cu₂O using DEA in the 280°C≤T_d≤310°C and AA in the 280°C≤T_d≤290°C ranges. These deposition temperatures are lower than the reported values (∼ 330 °C) using the same copper salt and glucose. This fact is associated with the reducing character of both agents since the obtained precursor solutions lead to an in-situ reduction. In addition, the films show minimum organic impurities content associated with the low volatilization temperature of the DEA and AA, which is desirable for their application in devices. The calculated bandgap energy (2.3–2.4 eV) for both types of films corresponds to nanocrystalline Cu₂O. However, using L-ascorbic acid resulted in thin films with the lowest resistivity (10² Ωcm), attributed to an improvement in the crystallinity.

Original language	English (US)
Article number	103999
Journal	Materials Today Communications
Volume	32
DOIs	https://doi.org/10.1016/j.mtcomm.2022.103999
State	Published - Aug 2022

Funding

CONACyT funded this research under project CB-2013-01-222909 . Furthermore, the authors want to thank CONACyT for the M. Sc. fellowship awarded to Mireny Ugalde Reygadas. Moreover, the authors thank the bestowed facilities for the LIDTRA infrastructure usage through the projects LN295261, LN254119, and LN299082. Also, thanks to Dr. Joaquín Márquez Marín, M. Sc. Reyna Araceli Mauricio Sánchez and B.Eng. José Eleazar Urbina Álvarez for the technical assistance in spray pyrolisis system, IR specular-reflectance and SEM measurements, respectively. This work made use of the Northwestern University Jerome B.Cohen X-Ray Diffraction Facility supported by the MRSEC program of the US National Science Foundation ( DMR-1720139 ) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource ( NSF ECCS-2025633 ).

Keywords

Cuprous oxide
Diethanolamine
L-ascorbic acid
Spray-pyrolysis
Thin films

ASJC Scopus subject areas

General Materials Science
Mechanics of Materials
Materials Chemistry

Access to Document

10.1016/j.mtcomm.2022.103999

Cite this

@article{3fe4de98b00e4dc3a68427c703e79add,

title = "Cu2O thin films deposited by spray pyrolysis using diethanolamine and L-ascorbic acid as reducing agents",

abstract = "Cu2O thin films are of great interest due to their diverse applications. Spray pyrolysis is a low-cost and straightforward technique among the different methods used to deposit them. Precursor solutions using D-glucose as reducing agent and copper acetate have mainly been used. However, the D-glucose's remaining subproduct can detriment the films' properties and use in devices. In this work, precursor solutions using diethanolamine (DEA) or L-ascorbic acid (AA) as reducing agents to deposit Cu2O thin films are used for the first time. The effect on the structural, morphological, electrical, and optical properties of Cu2O thin films is shown for 0.25 M of DEA and 0.1 M of AA, which were the optimal molar concentrations to obtain homogeneous solutions, with 0.04 M of copper nitrate. The deposition temperature (Td) determines the formation of Cu2O single phase. XRD analysis reveals films only constituted by Cu2O using DEA in the 280°C≤Td≤310°C and AA in the 280°C≤Td≤290°C ranges. These deposition temperatures are lower than the reported values (∼ 330 °C) using the same copper salt and glucose. This fact is associated with the reducing character of both agents since the obtained precursor solutions lead to an in-situ reduction. In addition, the films show minimum organic impurities content associated with the low volatilization temperature of the DEA and AA, which is desirable for their application in devices. The calculated bandgap energy (2.3–2.4 eV) for both types of films corresponds to nanocrystalline Cu2O. However, using L-ascorbic acid resulted in thin films with the lowest resistivity (102 Ωcm), attributed to an improvement in the crystallinity.",

keywords = "Cuprous oxide, Diethanolamine, L-ascorbic acid, Spray-pyrolysis, Thin films",

author = "M. Ugalde-Reygadas and Moreno-Regino, {Valeria D.} and Torres-Castanedo, {Carlos G.} and Bedzyk, {Michael J.} and Rebeca Castanedo-P{\'e}rez and Gerardo Torres-Delgado",

note = "Publisher Copyright: {\textcopyright} 2022 Elsevier Ltd",

year = "2022",

month = aug,

doi = "10.1016/j.mtcomm.2022.103999",

language = "English (US)",

volume = "32",

journal = "Materials Today Communications",

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T1 - Cu2O thin films deposited by spray pyrolysis using diethanolamine and L-ascorbic acid as reducing agents

AU - Ugalde-Reygadas, M.

AU - Moreno-Regino, Valeria D.

AU - Torres-Castanedo, Carlos G.

AU - Bedzyk, Michael J.

AU - Castanedo-Pérez, Rebeca

AU - Torres-Delgado, Gerardo

PY - 2022/8

Y1 - 2022/8

N2 - Cu2O thin films are of great interest due to their diverse applications. Spray pyrolysis is a low-cost and straightforward technique among the different methods used to deposit them. Precursor solutions using D-glucose as reducing agent and copper acetate have mainly been used. However, the D-glucose's remaining subproduct can detriment the films' properties and use in devices. In this work, precursor solutions using diethanolamine (DEA) or L-ascorbic acid (AA) as reducing agents to deposit Cu2O thin films are used for the first time. The effect on the structural, morphological, electrical, and optical properties of Cu2O thin films is shown for 0.25 M of DEA and 0.1 M of AA, which were the optimal molar concentrations to obtain homogeneous solutions, with 0.04 M of copper nitrate. The deposition temperature (Td) determines the formation of Cu2O single phase. XRD analysis reveals films only constituted by Cu2O using DEA in the 280°C≤Td≤310°C and AA in the 280°C≤Td≤290°C ranges. These deposition temperatures are lower than the reported values (∼ 330 °C) using the same copper salt and glucose. This fact is associated with the reducing character of both agents since the obtained precursor solutions lead to an in-situ reduction. In addition, the films show minimum organic impurities content associated with the low volatilization temperature of the DEA and AA, which is desirable for their application in devices. The calculated bandgap energy (2.3–2.4 eV) for both types of films corresponds to nanocrystalline Cu2O. However, using L-ascorbic acid resulted in thin films with the lowest resistivity (102 Ωcm), attributed to an improvement in the crystallinity.

AB - Cu2O thin films are of great interest due to their diverse applications. Spray pyrolysis is a low-cost and straightforward technique among the different methods used to deposit them. Precursor solutions using D-glucose as reducing agent and copper acetate have mainly been used. However, the D-glucose's remaining subproduct can detriment the films' properties and use in devices. In this work, precursor solutions using diethanolamine (DEA) or L-ascorbic acid (AA) as reducing agents to deposit Cu2O thin films are used for the first time. The effect on the structural, morphological, electrical, and optical properties of Cu2O thin films is shown for 0.25 M of DEA and 0.1 M of AA, which were the optimal molar concentrations to obtain homogeneous solutions, with 0.04 M of copper nitrate. The deposition temperature (Td) determines the formation of Cu2O single phase. XRD analysis reveals films only constituted by Cu2O using DEA in the 280°C≤Td≤310°C and AA in the 280°C≤Td≤290°C ranges. These deposition temperatures are lower than the reported values (∼ 330 °C) using the same copper salt and glucose. This fact is associated with the reducing character of both agents since the obtained precursor solutions lead to an in-situ reduction. In addition, the films show minimum organic impurities content associated with the low volatilization temperature of the DEA and AA, which is desirable for their application in devices. The calculated bandgap energy (2.3–2.4 eV) for both types of films corresponds to nanocrystalline Cu2O. However, using L-ascorbic acid resulted in thin films with the lowest resistivity (102 Ωcm), attributed to an improvement in the crystallinity.

KW - Cuprous oxide

KW - Diethanolamine

KW - L-ascorbic acid

KW - Spray-pyrolysis

KW - Thin films

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