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Hernandez S, Perez-Estebanez M, Cheuquepan W, Perales-Rondon JV, Heras A, Colina A. Raman, UV-Vis Absorption, and Fluorescence Spectroelectrochemistry for Studying the Enhancement of the Raman Scattering Using Nanocrystals Activated by Metal Cations. Anal Chem 2023; 95:16070-16078. [PMID: 37871281 PMCID: PMC10633809 DOI: 10.1021/acs.analchem.3c01172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 10/09/2023] [Indexed: 10/25/2023]
Abstract
Raman signal enhancement is fundamental to develop different analytical tools for chemical analysis, interface reaction studies, or new materials characterization, among others. Thus, phenomena such as surface-enhanced Raman scattering (SERS) have been used for decades to increase the sensitivity of Raman spectroscopy, leading to a huge development of this field. Recently, an alternative method to SERS for the amplification of Raman signals has been reported. This method, known as electrochemical surface oxidation-enhanced Raman scattering (EC-SOERS), has been experimentally described. However, to date, it has not yet been fully understood. In this work, new experimental data that clarify the origin of the Raman enhancement in SOERS are provided. The use of a complete and unique set of combined spectroelectrochemistry techniques, including time-resolved operando UV-vis absorption, fluorescence, and Raman spectroelectrochemistry, reveals that such enhancement is related to the generation of dielectric or semiconductor nanocrystals on the surface of the electrode and that the interaction between the target molecule and the dielectric substrate is mediated by metal cations. According to these results, the interaction metal electrode-nanocrystal-metal cation-molecule is proposed as being responsible for the Raman enhancement in Ag and Cu substrates. Elucidation of the origin of the Raman enhancement will help to promote the rational design of SOERS substrates as an attractive alternative to the well-known SERS phenomenon.
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Affiliation(s)
- Sheila Hernandez
- Department
of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain
| | - Martin Perez-Estebanez
- Department
of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain
| | - William Cheuquepan
- Department
of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain
- Bernal
Institute, University of Limerick (UL), Limerick V94 T9PX, Ireland
- Department
of Chemical Sciences, School of Natural Sciences, University of Limerick (UL), Limerick V94 T9PX, Ireland
| | - Juan V. Perales-Rondon
- Department
of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain
| | - Aranzazu Heras
- Department
of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain
| | - Alvaro Colina
- Department
of Chemistry, Universidad de Burgos, Pza. Misael Bañuelos s/n, E-09001 Burgos, Spain
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2
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Jin Z, Li X, Li T, Li Y. Graphdiyne (C nH 2n-2)-Based GDY/CuI/MIL-53(Al) S-Scheme Heterojunction for Efficient Hydrogen Evolution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15632-15641. [PMID: 36507799 DOI: 10.1021/acs.langmuir.2c02334] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Graphdiyne (g-CnH2n-2) is a new carbon material composed of sp and sp2 hybrid carbon atoms. Since the synthesis by Li's team, graphdiyne has been widely studied in other fields because of its excellent properties. In this paper, graphdiyne was synthesized from copper-containing materials and the composite GDY/CuI/MIL-53(Al) S-scheme heterojunction is prepared for photocatalytic cracking of water to produce hydrogen. First, GDY/CuI was prepared by organic synthesis, and then GDY/CuI was anchored on the surface of MIL-53(Al) by in situ ultrasonic stirring. After the continuous optimization of experimental conditions, the final hydrogen evolution rate is much higher than that of MIL-53(Al). This efficient photocatalytic performance can be attributed to the S-scheme heterojunction formed by the unique energy band arrangement. At the same time, the mechanism of charge transfer was demonstrated by in situ irradiation X-ray photoelectron spectroscopy. The strong interaction among the three strongly promotes the separation and transfer of photogenerated electron-hole pairs.
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Affiliation(s)
- Zhiliang Jin
- School of Chemistry and Chemical Engineering, Ningxia Key Laboratory of Solar Chemical Conversion Technology, Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan750021, People's Republic of China
| | - Xiaohong Li
- School of Chemistry and Chemical Engineering, Ningxia Key Laboratory of Solar Chemical Conversion Technology, Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan750021, People's Republic of China
| | - Teng Li
- School of Chemistry and Chemical Engineering, Ningxia Key Laboratory of Solar Chemical Conversion Technology, Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan750021, People's Republic of China
| | - Youji Li
- College of Chemistry and Chemical Engineering, Jishou University, Jishou, Hunan416000, People's Republic of China
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3
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Li Z, Wu H, Cao H, Liang L, Han Y, Yang J, Song Y, Burda C. Improved Ultrafast Carrier Relaxation and Charge Transfer Dynamics in CuI Films and Their Heterojunctions via Sn Doping. J Phys Chem Lett 2022; 13:9072-9078. [PMID: 36154177 DOI: 10.1021/acs.jpclett.2c02354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
CuI is one of the promising hole transport materials for perovskite solar cells. However, its tendency to form defects is currently limiting its use for device applications. Here, we report the successful improvement of CuI through Sn doping and the direct measurement of the carrier relaxation and interfacial charge-transfer processes in Sn-doped CuI films and their heterostructures. Femtosecond-transient absorption (fs-TA) measurements reveal that Sn doping effectively passivates the trap states within the bandgap of CuI. The I-V characteristics of heterostructures demonstrate drastic improvement in transport characteristics upon Sn doping. Fs-TA measurements further confirm that the CuSnI/ZnO heterojunction has a type-II configuration with ultrafast charge transfer (<280 fs). The charge transfer time of a CuI/ZnO heterostructure is ∼2.8 times slower than that of the CuSnI/ZnO heterostructure, indicating that Sn doping suppresses the interfacial states that retard the charge transfer. These results elucidate the effect of Sn doping on the performance of CuI-based heterostructures.
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Affiliation(s)
- Zhongguo Li
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu 215500, China
| | - Haijuan Wu
- Laboratory of Advanced Nano Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Hongtao Cao
- Laboratory of Advanced Nano Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Lingyan Liang
- Laboratory of Advanced Nano Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Yanbing Han
- Department of Physics, Harbin Institute of Technology, Harbin 150001, China
| | - Junyi Yang
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - Yinglin Song
- Department of Physics, Harbin Institute of Technology, Harbin 150001, China
| | - Clemens Burda
- Department of Chemistry, College of Arts and Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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4
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Balog Á, Samu GF, Pető S, Janáky C. The Mystery of Black TiO 2: Insights from Combined Surface Science and In Situ Electrochemical Methods. ACS MATERIALS AU 2021; 1:157-168. [PMID: 34841423 PMCID: PMC8609907 DOI: 10.1021/acsmaterialsau.1c00020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 11/28/2022]
Abstract
Titanium dioxide (TiO2) is often employed as a light absorber, electron-transporting material and catalyst in different energy and environmental applications. Heat treatment in a hydrogen atmosphere generates black TiO2 (b-TiO2), allowing better absorption of visible light, which placed this material in the forefront of research. At the same time, hydrogen treatment also introduces trap states, and the question of whether these states are beneficial or harmful is rather controversial and depends strongly on the application. We employed combined surface science and in situ electrochemical methods to scrutinize the effect of these states on the photoelectrochemical (PEC), electrocatalytic (EC), and charge storage properties of b-TiO2. Lower photocurrents were recorded with the increasing number of defect sites, but the EC and charge storage properties improved. We also found that the PEC properties can be enhanced by trap state passivation through Li+ ion intercalation in a two-step process. This passivation can only be achieved by utilizing small size cations in the electrolyte (Li+) but not with bulky ones (Bu4N+). The presented insights will help to resolve some of the controversies in the literature and also provide rational trap state engineering strategies.
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Affiliation(s)
- Ádám Balog
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary
| | - Gergely F Samu
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary
| | - Szabolcs Pető
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary
| | - Csaba Janáky
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary
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5
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Pishgar S, Gulati S, Strain JM, Liang Y, Mulvehill MC, Spurgeon JM. In Situ Analytical Techniques for the Investigation of Material Stability and Interface Dynamics in Electrocatalytic and Photoelectrochemical Applications. SMALL METHODS 2021; 5:e2100322. [PMID: 34927994 DOI: 10.1002/smtd.202100322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/17/2021] [Indexed: 06/14/2023]
Abstract
Electrocatalysis and photoelectrochemistry are critical to technologies like fuel cells, electrolysis, and solar fuels. Material stability and interfacial phenomena are central to the performance and long-term viability of these technologies. Researchers need tools to uncover the fundamental processes occurring at the electrode/electrolyte interface. Numerous analytical instruments are well-developed for material characterization, but many are ex situ techniques often performed under vacuum and without applied bias. Such measurements miss dynamic phenomena in the electrolyte under operational conditions. However, innovative advancements have allowed modification of these techniques for in situ characterization in liquid environments at electrochemically relevant conditions. This review explains some of the main in situ electrochemical characterization techniques, briefly explaining the principle of operation and highlighting key work in applying the method to investigate material stability and interfacial properties for electrocatalysts and photoelectrodes. Covered methods include spectroscopy (in situ UV-vis, ambient pressure X-ray photoelectron spectroscopy (APXPS), and in situ Raman), mass spectrometry (on-line inductively coupled plasma mass spectrometry (ICP-MS) and differential electrochemical mass spectrometry (DEMS)), and microscopy (in situ transmission electron microscopy (TEM), electrochemical atomic force microscopy (EC-AFM), electrochemical scanning tunneling microscopy (EC-STM), and scanning electrochemical microscopy (SECM)). Each technique's capabilities and advantages/disadvantages are discussed and summarized for comparison.
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Affiliation(s)
- Sahar Pishgar
- Conn Center for Renewable Energy Research, University of Louisville, Louisville, KY, 40292, USA
| | - Saumya Gulati
- Conn Center for Renewable Energy Research, University of Louisville, Louisville, KY, 40292, USA
| | - Jacob M Strain
- Conn Center for Renewable Energy Research, University of Louisville, Louisville, KY, 40292, USA
| | - Ying Liang
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Guangzhou, Guangdong, 510006, China
| | - Matthew C Mulvehill
- Conn Center for Renewable Energy Research, University of Louisville, Louisville, KY, 40292, USA
| | - Joshua M Spurgeon
- Conn Center for Renewable Energy Research, University of Louisville, Louisville, KY, 40292, USA
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6
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Yan T, Liu H, Jin Z. Graphdiyne Based Ternary GD-CuI-NiTiO 3 S-Scheme Heterjunction Photocatalyst for Hydrogen Evolution. ACS APPLIED MATERIALS & INTERFACES 2021; 13:24896-24906. [PMID: 34019381 DOI: 10.1021/acsami.1c04874] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
As the demand of fossil fuels continues to expand, hydrogen energy is considered a promising alternative energy. In this work, the NiTiO3-CuI-GD ternary system was successfully constructed based on morphology modulation and energy band structure design. First, the one-pot method was used to cleverly embed the cubes CuI in the stacked graphdiyne (GD) to prepare the hybrid CuI-GD, and CuI-GD was anchored on the surface of NiTiO3 by simple physical stirring. The unique spatial arrangement of the composite catalyst was utilized to improve the hydrogen production activity under light. Second, to combine various characterization tools and energy band structures, we proposed an step-scheme (S-scheme) heterojunction photocatalytic reaction mechanism, among them, the tubular NiTiO3 formed by the self-assembled of nanoparticles provided sufficient sites for the anchoring of CuI-GD, and the thin layer GD acted as an electron acceptor to capture a large number of electrons with the help of the conjugated carbon network; cubes CuI could consume holes in the reaction system; the loading of CuI-GD greatly improved the oxidation and reduction ability of the whole catalytic system. The S-scheme heterojunction accelerated the transfer of carriers and improved the separation efficiency. The experiment provides a new insight into the construction of an efficient and eco-friendly multicatalytic system.
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Affiliation(s)
- Teng Yan
- School of Chemistry and Chemical Engineering, Ningxia Key Laboratory of Solar Chemical Conversion Technology, Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, P. R. China
| | - Hua Liu
- School of Chemistry and Chemical Engineering, Ningxia Key Laboratory of Solar Chemical Conversion Technology, Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, P. R. China
| | - Zhiliang Jin
- School of Chemistry and Chemical Engineering, Ningxia Key Laboratory of Solar Chemical Conversion Technology, Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, P. R. China
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7
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Peng H, Wang X, Tian Y, Zou B, Yang F, Huang T, Peng C, Yao S, Yu Z, Yao Q, Rao G, Wang J. Highly Efficient Cool-White Photoluminescence of (Gua) 3Cu 2I 5 Single Crystals: Formation and Optical Properties. ACS APPLIED MATERIALS & INTERFACES 2021; 13:13443-13451. [PMID: 33715359 DOI: 10.1021/acsami.1c02503] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Zero-dimensional lead-free organic-inorganic hybrid metal halides have drawn attention as a result of their local metal ion confinement structure and photoelectric properties. Herein, a lead-free compound of (Gua)3Cu2I5 (Gua = guanidine) with a different metal ion confinement has been discovered, which possesses a unique [Cu2I5]3- face-sharing tetrahedral dimer structure. First-principles calculation demonstrates the inherent nature of a direct band gap for (Gua)3Cu2I5, and its band gap of ∼2.98 eV was determined by experiments. Worthy of note is that (Gua)3Cu2I5 exhibits a highly efficient cool-white emission peaking at 481 nm, a full-width at half-maximum of 125 nm, a large Stokes shift, and a photoluminescence quantum efficiency of 96%, originating from self-trapped exciton emission. More importantly, (Gua)3Cu2I5 single crystals have a reversible thermoinduced luminescence characteristic due to a structural transition scaled by the electron-phonon coupling coefficients, which can be converted back and forth between cool-white and yellow color emission by heating or cooling treatment within a short time. In brief, as-synthesized (Gua)3Cu2I5 shows great potential for application both in single-component white solid-state lighting and sensitive temperature scaling.
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Affiliation(s)
- Hui Peng
- Guangxi Key Lab of Processing for Nonferrous Metals and Featured Materials and Key Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education; School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
- Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Xinxin Wang
- Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Ye Tian
- Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Bingsuo Zou
- Guangxi Key Lab of Processing for Nonferrous Metals and Featured Materials and Key Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education; School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Fan Yang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Tao Huang
- Guangxi Key Lab of Processing for Nonferrous Metals and Featured Materials and Key Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education; School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Chengyu Peng
- Guangxi Key Lab of Processing for Nonferrous Metals and Featured Materials and Key Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education; School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Shangfei Yao
- Guangxi Key Lab of Processing for Nonferrous Metals and Featured Materials and Key Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education; School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Zongmian Yu
- Guangxi Key Lab of Processing for Nonferrous Metals and Featured Materials and Key Lab of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education; School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Qingrong Yao
- School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Guanghui Rao
- School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Jianping Wang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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8
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Abstract
Metal-halide perovskites transformed optoelectronics research and development during the past decade. They have also gained a foothold in photocatalytic and photoelectrochemical processes recently, but their sensitivity to the most commonly applied solvents and electrolytes together with their susceptibility to photocorrosion hinders such applications. Understanding the elementary steps of photocorrosion of these materials can aid the endeavor of realizing stable devices. In this Perspective, we discuss both thermodynamic and kinetic aspects of photocorrosion processes occurring at the interface of perovskite photocatalysts and photoelectrodes with different electrolytes. We show how combined in situ and operando electrochemical techniques can reveal the underlying mechanisms. Finally, we also discuss emerging strategies to mitigate photocorrosion (such as surface protection, materials and electrolyte engineering, etc.).
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Affiliation(s)
- Gergely F Samu
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Rerrich Square 1, Szeged H-6720, Hungary.,ELI-ALPS Research Institute, Wolfgang Sandner Street 3, Szeged H-6728, Hungary
| | - Csaba Janáky
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Rerrich Square 1, Szeged H-6720, Hungary.,ELI-ALPS Research Institute, Wolfgang Sandner Street 3, Szeged H-6728, Hungary
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9
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Raj V, Lu T, Lockrey M, Liu R, Kremer F, Li L, Liu Y, Tan HH, Jagadish C. Introduction of TiO 2 in CuI for Its Improved Performance as a p-Type Transparent Conductor. ACS APPLIED MATERIALS & INTERFACES 2019; 11:24254-24263. [PMID: 31251025 DOI: 10.1021/acsami.9b05566] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The challenges of making high-performance, low-temperature processed, p-type transparent conductors (TCs) have been the main bottleneck for the development of flexible transparent electronics. Though a few p-type transparent conducting oxides (TCOs) have shown promising results, they need high processing temperature to achieve the required conductivity which makes them unsuitable for organic and flexible electronic applications. Copper iodide is a wide band gap p-type semiconductor that can be heavily doped at low temperature (<100 °C) to achieve conductivity comparable or higher than many of the well-established p-type TCOs. However, as-processed CuI loses its transparency and conductivity with time in an ambient condition which makes them unsuitable for long-term applications. Herein, we propose CuI-TiO2 composite thin films as a replacement of pure CuI. We show that the introduction of TiO2 in CuI makes it more stable in ambient conditions while also improving its conductivity and transparency. A detailed comparative analysis between CuI and CuI-TiO2 composite thin films has been performed to understand the reasons for improved conductivity, transparency, and stability of CuI-TiO2 samples in comparison to pure CuI samples. The enhanced conductivity in CuI-TiO2 stems from the highly conductive space-charge layer formation at the CuI-TiO2 interface, whereas the improved transparency is due to reduced CuI grain growth mobility in the presence of TiO2. The improved stability of CuI-TiO2 in comparison to pure CuI is a result of inhibited recrystallization and grain growth, reduced loss of iodine, and limited oxidation of the CuI phase in the presence of TiO2. For optimized fraction of TiO2, an average transparency of ∼78% (in 450-800 nm region) and a resistivity of 14 mΩ·cm are achieved, while maintaining a relatively high mobility of ∼3.5 cm2 V-1 s-1 with hole concentration reaching as high as 1.3 × 1020 cm-3. Most importantly, this work opens up the possibility to design a new range of p-type transparent conducting materials using the CuI/insulator composite system such as CuI/SiO2, CuI/Al2O3, CuI/SiNx, and so forth.
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Affiliation(s)
| | | | | | - Rong Liu
- Secondary Ion Mass Spectrometry Facility, Office of the Deputy Vice-Chancellor (R&D) , Western Sydney University , Penrith , New South Wales 2751 , Australia
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10
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Samu GF, Scheidt RA, Balog Á, Janáky C, Kamat PV. Tuning the Excited-State Dynamics of CuI Films with Electrochemical Bias. ACS ENERGY LETTERS 2019; 4:702-708. [PMID: 30882041 PMCID: PMC6413481 DOI: 10.1021/acsenergylett.9b00182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 02/13/2019] [Indexed: 05/27/2023]
Abstract
Owing to its high hole conductivity and ease of preparation, CuI was among the first inorganic hole-transporting materials that were introduced early on in metal halide perovskite solar cells, but its full potential as a semiconductor material is still to be realized. We have now performed ultrafast spectroelectrochemical experiments on ITO/CuI electrodes to show the effect of applied bias on the excited-state dynamics in CuI. Under operating conditions, the recombination of excitons is dependent on the applied bias, and it can be accelerated by decreasing the potential from +0.6 to -0.1 V vs Ag/AgCl. Prebiasing experiments show the persistent and reversible "memory" effect of electrochemical bias on charge carrier lifetimes. The excitation of CuI in a CuI/CsPbBr3 film provides synergy between both CuI and CsPbBr3 in dictating the charge separation and recombination.
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Affiliation(s)
- Gergely F. Samu
- Radiation
Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department
of Physical Chemistry and Materials Science, Interdisciplinary Excellence
Centre, University of Szeged, Rerrich Square 1, Szeged H-6720, Hungary
- ELI-ALPS
Research Institute, Dugonics
Square 13, Szeged 6720, Hungary
| | - Rebecca A. Scheidt
- Radiation
Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department
of Chemistry and Biochemistry, University
of Notre Dame, Notre
Dame, Indiana 46556, United States
| | - Ádám Balog
- Department
of Physical Chemistry and Materials Science, Interdisciplinary Excellence
Centre, University of Szeged, Rerrich Square 1, Szeged H-6720, Hungary
| | - Csaba Janáky
- Department
of Physical Chemistry and Materials Science, Interdisciplinary Excellence
Centre, University of Szeged, Rerrich Square 1, Szeged H-6720, Hungary
- ELI-ALPS
Research Institute, Dugonics
Square 13, Szeged 6720, Hungary
| | - Prashant V. Kamat
- Radiation
Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department
of Chemistry and Biochemistry, University
of Notre Dame, Notre
Dame, Indiana 46556, United States
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