1
|
Lv J, Ning H. Photovoltaic Effect of La and Mn Co-Doped BiFeO 3 Heterostructure with Charge Transport Layers. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2072. [PMID: 38730875 PMCID: PMC11084247 DOI: 10.3390/ma17092072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 04/19/2024] [Accepted: 04/25/2024] [Indexed: 05/13/2024]
Abstract
Bismuth ferrite BiFeO3 (BFO)-based ferroelectrics have great potential as inorganic perovskite-like oxides for future solar cells applications due to their unique physical properties. In this work, La and Mn co-doped BFO thin films with compositions Bi0.9La0.1(Fe1-xMnx)O3 (x = 0, 0.05, 0.1, 0.15) (denoted as BLF, BLFM5, BLFM10, BLFM15, respectively) were prepared via a sol-gel technique on indium tin oxide (ITO) glass. All the films are monophasic, showing good crystallinity. The optical bandgap Eg was found to decrease monotonously with an increase in the Mn doping amount. Compared with other compositions, the BLFM5 sample exhibits a better crystallinity and less oxygen vacancies as indicated by XRD and XPS measurements, thereby achieving a better J-V performance. Based on BLFM5 as the light absorbing layer, the ITO/ZnO/BLFM5/Pt and ITO/ZnO/BLFM5/NiO/Pt heterostructure devices were designed and characterized. It was found that the introduction of the ZnO layer increases both the open circuit voltage (Voc) and the short circuit current density (Jsc) with Voc = 90.2 mV and Jsc = 6.90 μA/cm2 for the Pt/ BLFM5/ZnO/ITO device. However, the insertion of the NiO layer reduces both Voc and Jsc, which is attributed to the weakened built-in electric field at the NiO/BLFM5 interface.
Collapse
Affiliation(s)
| | - Huanpo Ning
- College of Science, Donghua University, Shanghai 201620, China;
| |
Collapse
|
2
|
Li X, Wang Z, Ji W, Lu T, You J, Wang K, Liu G, Liu Y, Wang L. Polarization Alignment in Polycrystalline BiFeO 3 Photoelectrodes for Tunable Band Bending. ACS NANO 2023; 17:22944-22951. [PMID: 37947409 DOI: 10.1021/acsnano.3c08081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Polarization in a semiconductor can modulate the band bending via the depolarization electric field (EdP), subsequently tuning the charge separation and transfer (CST) process in photoelectrodes. However, the random orientation of dipole moments in many polycrystalline semiconductor photoelectrodes leads to negligible polarization effect. How to effectively align the dipole moments in polycrystalline photoelectrodes into the same direction to maximize the polarization is still to be developed. Herein, we report that the dipole moments in a ferroelectric BiFeO3 photoelectrode can be controlled under external poling, resulting in a tunable CST efficiency. A negative bias of -40 voltage (V) poling to the photoelectrode leads to an over 110% increase of the CST efficiency, while poling at +40 V, the CST efficiency is reduced to only 41% of the original value. Furthermore, a nearly linear relationship between the external poling voltage and surface potential is discovered. The findings here provide an effective method in tuning the band bending and charge transfer of the emerging ferroelectricity driven solar energy conversion.
Collapse
Affiliation(s)
- Xianlong Li
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Zhiliang Wang
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Wenzhong Ji
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Teng Lu
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Jiakang You
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Kai Wang
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
- WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Perth, Western Australia 6102, Australia
| | - Gang Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, 72 Wenhua Road, Shenyang 110016, China
| | - Yun Liu
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Lianzhou Wang
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
| |
Collapse
|
3
|
Al-Najar B, Kamel AH, Albuflasa H, Hankins NP. Spinel ferrite nanoparticles as potential materials in chlorophenol removal from wastewater. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:104976-104997. [PMID: 37723389 DOI: 10.1007/s11356-023-29809-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 09/06/2023] [Indexed: 09/20/2023]
Abstract
Persistent organic pollutants (POPs) including chlorophenols (CPs) are increasing in water effluents, creating serious problems for both aquatic and terrestrial lives. Several research attempts have considered the removal of CPs by functionalised nanomaterials as adsorbents and catalysts. Besides the unique crystal structure, spinel ferrite nanomaterials (SFNs) own interesting optical and magnetic properties that give them the potential to be utilised in the removal of different types of CPs. In this review, we highlighted the recent research work that focused on the application of SFNs in the removal of different CP substances based on the number of chlorine atom attached to the phenolic compound. We have also discussed the structure and properties of SFN along with their numerous characterisation tools. We demonstrated the importance of identifying the structure, surface area, porosity, optical properties, etc. in the efficiency of the SFN during the CP removal process. The reviewed research efforts applied photocatalysis, wet peroxide oxidation (WPO), persulfate activated oxidation and adsorption. The studies presented different paths of enhancing the SFN ability to remove the CPs including doping (ion substitution), oxide composite structure and polymer composite structure. Experimental parameters such as temperature, dosage of CPs and SFN structure have shown to have a major effect in the CP removal efficiency. More attention is needed to investigate the different properties of SFN that can be tailored through different techniques and expected to have major role in the removal mechanism of CPs.
Collapse
Affiliation(s)
- Basma Al-Najar
- Department of Physics, University of Bahrain, P.O. Box 32038, Sakhir, Zallaq, Bahrain.
| | - Ayman H Kamel
- Department of Chemistry, University of Bahrain, P.O. Box 32038, Sakhir, Zallaq, Bahrain
- Department of Chemistry, Faculty of Science, Ain Shams University, Cairo, 11566, Egypt
| | - Hanan Albuflasa
- Department of Physics, University of Bahrain, P.O. Box 32038, Sakhir, Zallaq, Bahrain
| | - Nicholas P Hankins
- Department of Engineering Science, The University of Oxford, Parks Road, Oxford, OX3 1PJ, UK
| |
Collapse
|
4
|
Nagashree MC, Kulkarni SD, Rajendra BV, Seidel J, Murari MS, Sharma P. Spray pyrolysis-derived robust ferroelectric BiFeO 3 thin films. Phys Chem Chem Phys 2023; 25:22286-22293. [PMID: 37578066 DOI: 10.1039/d3cp02877a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Scalable and low-cost synthesis of high-quality ferroic films is critical for the development of advanced electronic devices and sensors. Here, we employ solution-based spray pyrolysis to fabricate bismuth ferrite thin films on glass substrates and explore the impact of annealing conditions to attain functional thin films of superior quality and switchable polarization. Optimised thin films display polycrystalline nanostructured grains with the highest X-ray diffraction intensity along the (110) orientation and a mixed Fe2+/3+ valence suggesting the presence of oxygen vacancies. The optimized films show a complex ferroelectric domain microstructure and exhibit robust nanoscale polarization switching in the range of several volts. Domains are found to scale with the sizes of nanocrystalline grains, which points to the role of surface-energy-related mechanisms affecting the domain patterns. Our results demonstrate the potential of spray pyrolysis for the fabrication of high-quality ferroelectric thin films and provide new opportunities for the development of low-cost scalable advanced electronic devices.
Collapse
Affiliation(s)
- M C Nagashree
- Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal-576104, India.
| | - S D Kulkarni
- Department of Atomic and Molecular Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal-576104, India.
| | - B V Rajendra
- Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal-576104, India.
| | - J Seidel
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, UNSW, Sydney, NSW, 2052, Australia
| | - M S Murari
- DST Purse Lab, Mangalore University, Mangalagangotri, Mangalore-574199, India
| | - P Sharma
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, UNSW, Sydney, NSW, 2052, Australia
- College of Science and Engineering, Flinders University, Bedford Park, Adelaide, SA, 5042, Australia.
- Flinders Institute for Nanoscale Science and Technology, Flinders University, Adelaide, SA, 5042, Australia
| |
Collapse
|
5
|
Zhang Z, Tan B, Ma W, Liu B, Sun M, Cooper JK, Han W. BiFeO 3 photocathodes for efficient H 2O 2 production via charge carrier dynamics engineering. MATERIALS HORIZONS 2022; 9:1999-2006. [PMID: 35608360 DOI: 10.1039/d2mh00201a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Metal oxide semiconductors are promising candidate photoelectrodes for photoelectrochemical H2O2 production if the issues of poor efficiency and selectivity can be resolved. An unfavorable charge transport barrier causes poor carrier collection and kinetics, limiting their efficiency and selectivity. Herein, BiFeO3 was used as the model photocathode, and its interfacial charge transport barrier between fluorine-doped tin oxide substrates was modulated by introducing a LaNiO3 layer as the charge collection layer. Our findings show the significantly enhanced photoelectrochemical activity of the composite photocathode with an improved photocurrent by three times (-0.9 mA cm-2 at 0.6 V vs. RHE) and the H2O2 formation up to 278 μmol L-1 with doubled faradaic efficiency. It is shown that these enhancements are due to the promoted charge carrier collection and kinetics. This work demonstrates the significant role of the charge collection layer in improving the collection and usage of photocarriers to accelerate the application of solar-to-fuel conversion.
Collapse
Affiliation(s)
- Zemin Zhang
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
| | - Bing Tan
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
| | - Wenjun Ma
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
| | - Bo Liu
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
| | - Mengdi Sun
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
| | - Jason K Cooper
- Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Weihua Han
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
| |
Collapse
|
6
|
Gomez-Iriarte GA, Pentón-Madrigal A, de Oliveira LAS, Sinnecker JP. XPS Study in BiFeO 3 Surface Modified by Argon Etching. MATERIALS 2022; 15:ma15124285. [PMID: 35744344 PMCID: PMC9227888 DOI: 10.3390/ma15124285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/25/2022] [Accepted: 06/02/2022] [Indexed: 02/04/2023]
Abstract
This paper reports an XPS surface study of pure phase BiFeO3 thin film produced and later etched by pure argon ions. Analysis of high-resolution spectra from Fe 2p, Bi 4f and 5d, O 1s, and the valence band, exhibited mainly Fe3+ and Bi3+ components, but also reveal Fe2+. High-energy argon etching induces the growth of Fe(0) and Bi(0) and an increment of Fe2+, as expected. The BiFeO3 semiconductor character is preserved despite the oxygen loss, an interesting aspect for the study of the photovoltaic effect through oxygen vacancies in some ceramic films. The metal-oxygen bonds in O 1s spectra are related only to one binding energy contrary to the split from bismuth and iron reported in other works. All these data evidence that the low-pressure argon atmosphere is proved to be efficient to produce pure phase BiFeO3, even after argon etching.
Collapse
Affiliation(s)
- Grecia Alejandra Gomez-Iriarte
- Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, Rio de Janeiro 22290-180, RJ, Brazil
- Correspondence: (G.A.G.-I.); (J.P.S.); Tel.: +55-21-2141-7173 (G.A.G.-I.); +55-21-2141-7509 (J.P.S.)
| | | | - Luiz Augusto Sousa de Oliveira
- Núcleo Multidisciplinar de Pesquisas em Nanotecnologia, Universidade Federal do Rio de Janeiro, Rodovia Washington Luiz, km 104, 5, Duque de Caxias 25240-005, RJ, Brazil;
| | - João Paulo Sinnecker
- Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, Rio de Janeiro 22290-180, RJ, Brazil
- Correspondence: (G.A.G.-I.); (J.P.S.); Tel.: +55-21-2141-7173 (G.A.G.-I.); +55-21-2141-7509 (J.P.S.)
| |
Collapse
|
7
|
Sun M, Zhou K, Ji X, Zheng H, Zhang Y. Growth of Y3Fe5O12-BaFe12O19 nanocomposite film with high remanence ratio for its exchange spring coupling behavior. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.139113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
8
|
Sun Z, Wei J, Yang T, Li Y, Liu Z, Chen G, Wang T, Sun H, Cheng Z. Integrating Band Engineering and the Flexoelectric Effect Induced by a Composition Gradient for High Photocurrent Density in Bismuth Ferrite Films. ACS APPLIED MATERIALS & INTERFACES 2021; 13:49850-49859. [PMID: 34643367 DOI: 10.1021/acsami.1c13305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Photovoltaic energy as one of the important alternatives to traditional fossil fuels has always been a research hot spot in the field of renewable and clean solar energy. Very recently, the anomalous ferroelectric photovoltaic effect in multiferroic bismuth ferrite (BiFeO3) has attracted much attention due to the above-bandgap photovoltage and switchable photocurrent. However, its photocurrent density mostly in the magnitudes of μA/cm2 resulted in a poor power conversion efficiency, which severely hampered its practical application as a photovoltaic device. In this case, a novel approach was designed to improve the photocurrent density of BiFeO3 through the cooperative effect of the gradient distribution of oxygen vacancies and consequently induced the flexoelectric effect realized in the (La, Co) gradient-doped BiFeO3 multilayers. Subsequent results and analysis indicated that the photocurrent density of the gradient-doped multilayer BiFeO3 sample was nearly 3 times as much as that of the conventional doped single-layer sample. Furthermore, a possible mechanism was proposed herein to demonstrate roles of band engineering and the flexoelectric effect on the photovoltaic performance of the gradient-doped BiFeO3 film.
Collapse
Affiliation(s)
- Zehao Sun
- Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education & Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Jie Wei
- Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education & Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Tiantian Yang
- Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education & Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Yunpeng Li
- Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education & Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Zhiting Liu
- Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education & Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Guogang Chen
- Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education & Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Tiangang Wang
- Lanzhou Institute of Physics, Lanzhou 730000, P. R. China
| | - Hai Sun
- Lanzhou Institute of Physics, Lanzhou 730000, P. R. China
| | - Zhenxiang Cheng
- Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, Innovation Campus, Squires Way, North Wollongong, NSW 2500, Australia
| |
Collapse
|
9
|
Lei L, Liu L, Lu X, Mei F, Shen H, Hu X, Yan S, Huang F, Zhu J. Controllable Distribution and Reversible Migration of Charges in BiFeO 3-Based Films on Si Substrates. ACS APPLIED MATERIALS & INTERFACES 2021; 13:43787-43794. [PMID: 34467752 DOI: 10.1021/acsami.1c14060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In ferroelectric-based integrated devices, there are usually buffer layers between ferroelectric films and semiconductor substrates. Here, Bix%FeO3-δ (x = 95, 100, and 105) (BFOx) films are prepared directly on n-Si substrates by the sol-gel method, and the variation of the hysteresis loops with Bi content and heat treatment is investigated. With the help of the dielectric measurement and the composition analysis, a PN heterojunction is believed to exist at the BFOx/Si interface. The Bi/Fe ratio determines not only the type and concentration of charged defects in the films but also the height of the interface barrier and its binding effect on mobile charges. Furthermore, the distribution and the migration of charges can be regulated reversibly by heat treatment. This work reveals the interaction between ferroelectric films and semiconductor substrates, providing an important reference for the design and application of ferroelectric/semiconductor heterostructures.
Collapse
Affiliation(s)
- Lin Lei
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
| | - Lin Liu
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
| | - Xiaomei Lu
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - Fang Mei
- Department of Mathematics and Physics, Luoyang Institute of Science and Technology, Luoyang 471023, China
| | - Hui Shen
- School of Information and Electronic Engineering, Shandong Technology and Business University, Yantai 264005, China
| | - Xueli Hu
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
| | - Shuo Yan
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
| | - Fengzhen Huang
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - Jinsong Zhu
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| |
Collapse
|
10
|
Gao H, Zhang J, Wei X, Zhu Q, Wei T. Enhanced electrochemiluminescence cytosensing based on abundant oxygen vacancies contained 2D nanosheets emitter coupled with DNA device cycle-amplification. Talanta 2021; 228:122230. [DOI: 10.1016/j.talanta.2021.122230] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/06/2021] [Accepted: 02/13/2021] [Indexed: 11/28/2022]
|
11
|
Investigation of Local Conduction Mechanisms in Ca and Ti-Doped BiFeO 3 Using Scanning Probe Microscopy Approach. NANOMATERIALS 2020; 10:nano10050940. [PMID: 32422891 PMCID: PMC7279369 DOI: 10.3390/nano10050940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/08/2020] [Accepted: 05/12/2020] [Indexed: 11/26/2022]
Abstract
In this work we demonstrate the role of grain boundaries and domain walls in the local transport properties of n- and p-doped bismuth ferrites, including the influence of these singularities on the space charge imbalance of the energy band structure. This is mainly due to the charge accumulation at domain walls, which is recognized as the main mechanism responsible for the electrical conductivity in polar thin films and single crystals, while there is an obvious gap in the understanding of the precise mechanism of conductivity in ferroelectric ceramics. The conductivity of the Bi0.95Ca0.05Fe1−xTixO3−δ (x = 0, 0.05, 0.1; δ = (0.05 − x)/2) samples was studied using a scanning probe microscopy approach at the nanoscale level as a function of bias voltage and chemical composition. The obtained results reveal a distinct correlation between electrical properties and the type of charged defects when the anion-deficient (x = 0) compound exhibits a three order of magnitude increase in conductivity as compared with the charge-balanced (x = 0.05) and cation-deficient (x = 0.1) samples, which is well described within the band diagram representation. The data provide an approach to control the transport properties of multiferroic bismuth ferrites through aliovalent chemical substitution.
Collapse
|
12
|
Nandy S, Kaur K, Gautam S, Chae KH, Nanda BRK, Sudakar C. Maximizing Short Circuit Current Density and Open Circuit Voltage in Oxygen Vacancy-Controlled Bi 1-xCa xFe 1-yTi yO 3-δ Thin-Film Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2020; 12:14105-14118. [PMID: 32118399 DOI: 10.1021/acsami.9b18357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Designing solid-state perovskite oxide solar cells with large short circuit current (JSC) and open circuit voltage (VOC) has been a challenging problem. Epitaxial BiFeO3 (BFO) films are known to exhibit large VOC (>50 V). However, they exhibit low JSC (≪μA/cm2) under 1 Sun illumination. In this work, taking polycrystalline BiFeO3 thin films, we demonstrate that oxygen vacancies (VO) present within the lattice and at grain boundary (GB) can explicitly be controlled to achieve high JSC and VOC simultaneously. While aliovalent substitution (Ca2+ at Bi3+ site) is used to control the lattice VO, Ca and Ti cosubstitution is used to bring out only GB-VO. Fluorine-doped tin oxide (FTO)/Bi1-xCaxFe1-yTiyO3-δ/Au devices are tested for photovoltaic characteristics. Introducing VO increases the photocurrent by four orders (JSC ∼ 3 mA/cm2). On the contrary, VOC is found to be <0.5 V, as against 0.5-3 V observed for the pristine BiFeO3. Ca and Ti cosubstitution facilitate the formation of smaller crystallites, which in turn increase the GB area and thereby the GB-VO. This creates defect bands occupying the bulk band gap, as inferred from the diffused reflection spectra and band structure calculations, leading to a three-order increase in JSC. The cosubstitution, following a charge compensation mechanism, decreases the lattice VO concentration significantly to retain the ferroelectric nature with enhanced polarization. It helps to achieve VOC (3-8 V) much larger than that of BiFeO3 (0.5-3 V). It is noteworthy that as Ca substitution maintains moderate crystallite size, the lattice VO concentration dominates GB-VO concentration. Notwithstanding, both lattice and GB-VO contribute to the increase in JSC; the former weakens ferroelectricity, and as a consequence, undesirably, VOC is lowered well below 0.5 V. Using optimum JSC and VOC, we demonstrate that the efficiency ∼0.22% can be achieved in solid-state BFO solar cells under AM 1.5 one Sun illumination.
Collapse
Affiliation(s)
- Subhajit Nandy
- Multifunctional Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Kulwinder Kaur
- Condensed Matter Theory and Computational Lab, Department of Physics, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Sanjeev Gautam
- Advanced Functional Materials Lab, Dr. S. S. Bhatnagar University Institute of Chemical Engineering & Technology, Punjab University, Chandigarh 160014, India
| | - Keun Hwa Chae
- Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - B R K Nanda
- Condensed Matter Theory and Computational Lab, Department of Physics, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Chandran Sudakar
- Multifunctional Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600 036, India
| |
Collapse
|