Electrochemically deposited p–n homojunction cuprous oxide solar cells

Han, Kunhee; Tao, Meng

doi:10.1016/j.solmat.2008.09.023

Cited by 217 publications

(133 citation statements)

References 13 publications

Supporting

Mentioning

111

Contrasting

Order By: Relevance

“…They concluded that the central copper(II) (bearing the oxygen atoms) is four coordinated. 19 Furthermore, according to their structure-model fitting, CuL 4 2-is more likely to be the dissolved copper(II)-lactate complex, assuming that excess L -acts as a monodentate ligand, rather than a bidentate ligand. They did not discuss the possibility of α-hydroxyl-group deprotonate to form H -1 L 2-from L -.…”

Section: Esi-ms/pesi-ms-the Titration Results Suggested the Existencmentioning

confidence: 99%

“…6,15,16 Unfortunately, to the best of our knowledge, there are no available thermodynamic data for these copper(II)-lactate complexes under these alkaline conditions, especially for such concentrated solutions. Two previous reports have indicated the presence of dissolved copper(II)-lactate complexes in such concentrated alkaline solutions; Leopold et al assumed that the copper(II)-lactate complexes are Cu(H -1 L) 2 2-and Cu(H -1 L) 2 (OH) 3-(H -1 L 2-= CH 3 CH(O -)COO -, the lactate ion bearing a deprotonated α-hydroxyl group) based on a pH-titration experiment at pH > 8, and by analogy with the alkaline copper(II)-tartrate system, 18 while Achilli et al proposed CuL 4 2-on the basis of energy-dispersive X-ray absorption spectroscopy (EDXAS), where they assumed that L -functions unusually as a monodentate ligand. 19 These different results leave the copper(II)-lactate complexes in these Cu 2 O-electrodeposition baths open to question; consequently, other direct information is required.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Chen

Kitada

Seki

et al. 2018

J. Electrochem. Soc.

View full text Add to dashboard Cite

Unveiling dissolved species in electrodeposition baths helps our understanding of electrodeposition behavior, such as growth orientation. A highly concentrated aqueous alkaline copper(II)-lactate solution is used for the electrodeposition of copper(I) oxide (Cu 2 O) thin films with <111> orientations; the semiconductor properties of these films facilitate their use in solar-cell materials, photocathodes, and photocatalysts. However, the dissolved species, presumably copper(II)-lactate complexes, cannot be deduced on the basis of known thermodynamic data, and have not been convincingly determined yet. In this work, we determine these cupric complexes by pH titration, ultraviolet-visible spectroscopy, and electrospray-ionization mass spectrometry (ESI-MS), including probe-ESI-MS (PESI-MS). Using PESI-MS, we successfully analyzed a highly concentrated solution without sample dilution. The determined complexes are Cu(H -1 L)L -and Cu(H -1 L) 2 2-, where the H -1 L 2-(CH 3 CH(O -)COO -) is a lactate ion with a deprotonated α-hydroxyl group. As far as we know, this is the first direct experimental observation of H -1 L 2-ions in a highly concentrated aqueous alkaline copper(II)-lactate solution. We also propose that H -1 L 2-is stabilized by the high concentration and through coordination to copper(II) ions. Cuprous oxide (Cu 2 O) is a p-type semiconductor that is inexpensive and of low toxicity. Cu 2 O thin films are attracting increasing attention as solar-cell materials, 1-5 photocathodes, 6-9 and photocatalysts 10-12 for, for example, water splitting. Among thin-film fabrication methods, electrodeposition from an aqueous solution has advantages over conventional methods, such as chemical vapor deposition, because of its low cost and low environmental burden. Moreover, it is easy to obtain cubic Cu 2 O with the preferential <111> orientation by tuning the pH of the electrodeposition bath;13-17 this orientation relaxes lattice misfit with hexagonal ZnO, which is favorable for Cu 2 O-ZnO solar cells.Since the pioneering work of Rakhshani et al., 13 highly concentrated aqueous alkaline solutions have commonly been used for Cu 2 O electrodeposition;13-16 these solutions contain 0.4 M of a copper(II) salt and 3.0 M lactic acid (HL; CH 3 CH(OH)COOH) as the complexing agent, and the pH is adjusted to be in the 9.0-12.5 range. [13][14][15][16] The crystal orientation of the electrodeposited Cu 2 O is pH dependent; i.e. it is <100> at pH values of 9.0 and 9.5, and <111> at pH values of 12.0 and 12.5. [13][14][15][16][17] The pH dependence of the crystal orientation during Cu 2 O electrodeposition may be ascribable to changes in the dissolved copper(II)-lactate complexes. 6,15,16 Unfortunately, to the best of our knowledge, there are no available thermodynamic data for these copper(II)-lactate complexes under these alkaline conditions, especially for such concentrated solutions. Two previous reports have indicated the presence of dissolved copper(II)-lactate complexes in such concentrated alkaline solutions; Leopold et al. a...

show abstract

Section: Esi-ms/pesi-ms-the Titration Results Suggested the Existencmentioning

confidence: 99%

mentioning

confidence: 99%

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Chen

Kitada

Seki

et al. 2018

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…However, research papers on cuprous oxide are still published in the second half of the 20th century 124 and even in the 21st century. 125,126 Germanium was once the main semiconductor used for transistors. Professor Karl Lark-Horovitz, Department of Physics of Purdue University, put in a great effort to study it during World War II.…”

Section: Semiconductor Science and Technology In The 21 St Centurymentioning

confidence: 99%

Introduction to the History of Semiconductors

Lau¹

2017

ULSI Front-End Technology

View full text Add to dashboard Cite

“…Tang et al (2005) found that the band gap of nanocrystalline Cu 2 O thin films is 2.06 eV, while Siripala et al (1996) found that the deposited cuprous oxide exhibits a direct band gap of 2.0 eV, and shows an n-type behavior when used in a liquid/solid junction. Han & Tao (2009) found that n-type Cu 2 O deposited in a solution containing 0.01 M copper acetate and 0.1 M sodium acetate exhibits higher resistivity than p-type Cu 2 O deposited at pH 13 by two orders of magnitude. Other authors, like Singh et al (2008) estimated the band gap of prepared Cu 2 O nanothreads and nanowires to be 2.61 and 2.69 eV, which is larger than the direct band gap (2.17 eV) of bulk Cu 2 O (Wong & Searson, 1999).…”

Section: Introductionmentioning

confidence: 96%

Cuprous Oxide as an Active Material for Solar Cells

Bugarinović¹,

Rajčić-Vujasinović²,

Stević³

et al. 2011

Solar Cells - New Aspects and Solutions

View full text Add to dashboard Cite

Electrochemically deposited p–n homojunction cuprous oxide solar cells

Cited by 217 publications

References 13 publications

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Introduction to the History of Semiconductors

Cuprous Oxide as an Active Material for Solar Cells

Contact Info

Product

Resources

About

Electrochemically deposited p–n homojunction cuprous oxide solar cells

Cited by 217 publications

References 13 publications

Identification of Copper(II)–Lactate Complexes in Cu2O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Identification of Copper(II)–Lactate Complexes in Cu2O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Introduction to the History of Semiconductors

Cuprous Oxide as an Active Material for Solar Cells

Contact Info

Product

Resources

About

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution

Identification of Copper(II)–Lactate Complexes in Cu₂O Electrodeposition Baths: Deprotonation of the α-Hydroxyl Group in Highly Concentrated Alkaline Solution