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Electrical conduction and noise spectroscopy of sodium-alginate gold-covered ultrathin films for flexible green electronics. Sci Rep 2022; 12:9861. [PMID: 35701600 PMCID: PMC9198047 DOI: 10.1038/s41598-022-14030-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/18/2022] [Indexed: 12/15/2022] Open
Abstract
Green electronics is an emerging topic that requires the exploration of new methodologies for the integration of green components into electronic devices. Therefore, the development of alternative and eco-friendly raw materials, biocompatible and biodegradable, is of great importance. Among these, sodium-alginate is a natural biopolymer extracted from marine algae having a great potential in terms of transparency, flexibility, and conductivity, when functionalized with a thin gold (Au) layer. The electrical transport of these flexible and conducting substrates has been studied, by DC measurements, from 300 to 10 K, to understand the interplay between the organic substrate and the metallic layer. The results were compared to reference bilayers based on polymethyl-methacrylate, a well-known polymer used in electronics. In addition, a detailed investigation of the electric noise properties was also performed. This analysis allows to study the effect of charge carriers fluctuations, providing important information to quantify the minimum metallic thickness required for electronic applications. In particular, the typical noise behavior of metallic compounds was observed in samples covered with 5 nm of Au, while noise levels related to a non-metallic conduction were found for a thickness of 4.5 nm, despite of the relatively good DC conductance of the bilayer.
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Abstract
Electric noise spectroscopy is a non-destructive and a very sensitive method for studying the dynamic behaviors of the charge carriers and the kinetic processes in several condensed matter systems, with no limitation on operating temperatures. This technique has been extensively used to investigate several perovskite compounds, manganese oxides (La1−xSrxMnO3, La0.7Ba0.3MnO3, and Pr0.7Ca0.3MnO3), and a double perovskite (Sr2FeMoO6), whose properties have recently attracted great attention. In this work are reported the results from a detailed electrical transport and noise characterizations for each of the above cited materials, and they are interpreted in terms of specific physical models, evidencing peculiar properties, such as quantum interference effects and charge density waves.
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Kumar A, Bansode U, Ogale S, Rahman A. Understanding the thermal degradation mechanism of perovskite solar cells via dielectric and noise measurements. NANOTECHNOLOGY 2020; 31:365403. [PMID: 32470953 DOI: 10.1088/1361-6528/ab97d4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Long term stability is a major obstacle to the success of perovskite solar cell (PSC) photovoltaic technology. PSC performance deteriorates significantly in the presence of humidity, oxygen and exposure to UV light and heat. Here the change in charge transport properties of PSC with temperature and the associated significant drop in device performance at high temperature have been investigated. The latter is shown to be primarily due to an increase in charge carrier recombination, which impacts the open-circuit voltage. To understand the pathway of temperature-induced degradation, low-frequency 1/f noise characteristics, and the capacitance-frequency, as well as capacitance-voltage characteristics have been investigated under various conditions. The results show that at high operating temperature accumulation of ions and charge carriers at the interface increase the surface recombination. Aging experiments at different temperatures show high stability of PSCs up to temperature <70 °C, but a drastic, irreversible degradation occurs at higher temperature (≥80 °C). Low-frequency 1/f noise study revealed that the magnitude of normalized noise in degraded perovskite solar cells is four orders of magnitude higher than the pristine device. This study shows the power of low-frequency noise measurement technique as a highly sensitive non-invasive tool to study the degradation mechanism of PSCs.
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Affiliation(s)
- Ankit Kumar
- Department of Physics and Centre for Energy Science, Indian Institute of Science Education and Research (IISER)-Pune, Pune, Maharashtra 411008 India
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Kuiri M, Das S, Muthu DVS, Das A, Sood AK. Thickness dependent transition from the 1T' to Weyl semimetal phase in ultrathin MoTe 2: electrical transport, noise and Raman studies. NANOSCALE 2020; 12:8371-8378. [PMID: 32238996 DOI: 10.1039/c9nr10383j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bulk 1T'-MoTe2 shows a structural phase transition from the 1T' to Weyl semimetallic (WSM) Td phase at ∼240 K. This phase transition and transport properties in the two phases have not been investigated on ultra-thin crystals. Here we report electrical transport, 1/f noise and Raman studies on ultra-thin 1T'-MoTe2 (∼5 to 16 nm thick) field-effect transistor (FETs) devices as a function of temperature. The electrical resistivities for a thickness of 16 nm and 11 nm show maxima at temperatures of 208 K and 178 K, respectively, making a transition from the semiconducting to semi-metallic phase, hitherto not observed in bulk samples. Raman frequencies and linewidths for an 11 nm thick crystal show a change around 178 K, attributed to the additional contribution to the phonon self-energy due to the enhanced electron-phonon interaction in the WSM phase. Furthermore, the resistivity at low temperature shows an upturn below 20 K along with the maximum in the power spectral density of the low frequency 1/f noise. The latter rules out the metal-insulator transition (MIT) being responsible for the upturn of resistivity below 20 K. The low temperature resistivity follows ρ∝ 1/T, changing to ρ∝T with increasing temperature supports electron-electron interaction physics at electron-hole symmetric Weyl nodes below 20 K. These observations will pave the way to unravel the properties of the WSM state in layered ultra-thin van der Waals materials.
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Affiliation(s)
- Manabendra Kuiri
- Department of Physics, Indian Institute of Science, Bangalore 560012, India.
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Barone C, Mauro C, Sambri A, Scotti di Uccio U, Pagano S. Conductivity response of amorphous oxide interfaces to pulsed light illumination. NANOTECHNOLOGY 2019; 30:254005. [PMID: 30889555 DOI: 10.1088/1361-6528/ab110d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two-dimensional electron gases (2DEGs) formed at oxide interfaces show a large variety of functional properties of major physical interest. Here, the peculiar electric transport behavior of the 2DEG formed at the LGO/STO oxide interface is studied under the application of light pulses of different amplitude, duration, and repetition rate, and by varying the sample temperature from 8 to 300 K. The experimental results evidence a persistent photoconductivity, intimately related to the complex physics of this system. These findings suggest the possibility of using the oxide interfaces for advanced applications as, for example, energy conversion or information storage.
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Affiliation(s)
- C Barone
- Dipartimento di Fisica 'E.R. Caianiello' and CNR-SPIN Salerno, Università di Salerno, I-84084 Fisciano, Salerno, Italy
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Sangwan VK, Zhu M, Clark S, Luck KA, Marks TJ, Kanatzidis MG, Hersam MC. Low-Frequency Carrier Kinetics in Perovskite Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2019; 11:14166-14174. [PMID: 30896169 DOI: 10.1021/acsami.9b03884] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Hybrid organic-inorganic halide perovskite solar cells have emerged as leading candidates for third-generation photovoltaic technology. Despite the rapid improvement in power conversion efficiency (PCE) for perovskite solar cells in recent years, the low-frequency carrier kinetics that underlie practical roadblocks such as hysteresis and degradation remain relatively poorly understood. In an effort to bridge this knowledge gap, we perform here correlated low-frequency noise (LFN) and impedance spectroscopy (IS) characterization that elucidates carrier kinetics in operating perovskite solar cells. Specifically, we focus on planar cell geometries with a SnO2 electron transport layer and two different hole transport layers-namely, poly(triarylamine) (PTAA) and spiro-OMeTAD. PTAA and spiro-OMeTAD cells with moderate PCEs of 5-12% possess a Lorentzian feature at ∼200 Hz in LFN measurements that corresponds to a crossover from electrode to dielectric polarization. In comparison, spiro-OMeTAD cells with high PCEs (>15%) show 4 orders of magnitude lower LFN amplitude and are accompanied by a cyclostationary process. Through a systematic study of more than a dozen solar cells, we establish a correlation with noise amplitude, PCE, and fill factor. Overall, this work establishes correlated LFN and IS as an effective methodology for quantifying low-frequency carrier kinetics in perovskite solar cells, thereby providing new physical insights that can rationally guide ongoing efforts to improve device performance, reproducibility, and stability.
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Affiliation(s)
| | - Menghua Zhu
- Wuhan National Laboratory for Optoelectronics (WNLO) , Huazhong University of Science and Technology (HUST) , Wuhan 430074 , China
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Shen Q, Ng A, Ren Z, Gokkaya HC, Djurišić AB, Zapien JA, Surya C. Characterization of Low-Frequency Excess Noise in CH 3NH 3PbI 3-Based Solar Cells Grown by Solution and Hybrid Chemical Vapor Deposition Techniques. ACS APPLIED MATERIALS & INTERFACES 2018; 10:371-380. [PMID: 29094597 DOI: 10.1021/acsami.7b10091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study, detailed investigations of low-frequency noise (LFN) characteristics of hybrid chemical vapor deposition (HCVD)- and solution-grown CH3NH3PbI3 (MAPI) solar cells are reported. It has been shown that LFN is a ubiquitous phenomenon observed in all semiconductor devices. It is the smallest signal that can be measured from the device; hence, systematic characterization of the LFN properties can be utilized as a highly sensitive nondestructive tool for the characterization of material defects in the device. It has been demonstrated that the noise power spectral densities of the devices are critically dependent on the parameters of the fabrication process, including the growth ambient of the perovskite layer and the incorporation of the mesoscopic structures in the devices. Our experimental results indicated that the LFN arises from a thermally activated trapping and detrapping process, resulting in the corresponding fluctuations in the conductance of the device. The results show that the presence of oxygen in the growth ambient of the HCVD process and the inclusion of an mp-TiO2 layer in the device structure are two important factors contributing to the substantial reduction in the density of the localized states in the MAPI devices. Furthermore, the lifetimes of the MAPI perovskite-based solar cells are strongly dependent on the material defect concentration. The degradation process is substantially more rapid for the devices with higher initial defect density compared to the devices prepared under optimized conditions and structure that exhibit substantially lower initial trap density.
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Affiliation(s)
- Qian Shen
- Department of Electronic and Information Engineering, The Hong Kong Polytechnic University , Kowloon, Hong Kong SAR
| | - Annie Ng
- Department of Electronic and Information Engineering, The Hong Kong Polytechnic University , Kowloon, Hong Kong SAR
| | - Zhiwei Ren
- Department of Electronic and Information Engineering, The Hong Kong Polytechnic University , Kowloon, Hong Kong SAR
| | - Huseyin Cem Gokkaya
- Department of Electronic and Information Engineering, The Hong Kong Polytechnic University , Kowloon, Hong Kong SAR
| | - Aleksandra B Djurišić
- Department of Physics, The University of Hong Kong , Pokfulam, Hong Kong Island, Hong Kong SAR
| | - Juan Antonio Zapien
- Department of Physics and Materials Science, City University of Hong Kong , Kowloon, Hong Kong SAR
| | - Charles Surya
- Department of Electronic and Information Engineering, The Hong Kong Polytechnic University , Kowloon, Hong Kong SAR
- School of Engineering, Nazarbayev University , 53 Kabanbay Batyr Avenue, Astana 010000, Kazakhstan
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Landi G, Neitzert HC, Barone C, Mauro C, Lang F, Albrecht S, Rech B, Pagano S. Correlation between Electronic Defect States Distribution and Device Performance of Perovskite Solar Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2017; 4:1700183. [PMID: 29051860 PMCID: PMC5644241 DOI: 10.1002/advs.201700183] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/12/2017] [Indexed: 05/06/2023]
Abstract
In the present study, random current fluctuations measured at different temperatures and for different illumination levels are used to understand the charge carrier kinetics in methylammonium lead iodide CH3NH3PbI3-based perovskite solar cells. A model, combining trapping/detrapping, recombination mechanisms, and electron-phonon scattering, is formulated evidencing how the presence of shallow and deeper band tail states influences the solar cell recombination losses. At low temperatures, the observed cascade capture process indicates that the trapping of the charge carriers by shallow defects is phonon assisted directly followed by their recombination. By increasing the temperature, a phase modification of the CH3NH3PbI3 absorber layer occurs and for temperatures above the phase transition at about 160 K the capture of the charge carrier takes place in two steps. The electron is first captured by a shallow defect and then it can be either emitted or thermalize down to a deeper band tail state and recombines subsequently. This result reveals that in perovskite solar cells the recombination kinetics is strongly influenced by the electron-phonon interactions. A clear correlation between the morphological structure of the perovskite grains, the energy disorder of the defect states, and the device performance is demonstrated.
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Affiliation(s)
- Giovanni Landi
- Dipartimento di Ingegneria Industriale (DIIn)Università di SalernoVia Giovanni Paolo II 13284084Fisciano (SA)Italy
| | - Heinz Christoph Neitzert
- Dipartimento di Ingegneria Industriale (DIIn)Università di SalernoVia Giovanni Paolo II 13284084Fisciano (SA)Italy
| | - Carlo Barone
- Dipartimento di Fisica “E.R. Caianiello” and CNR‐SPIN SalernoUniversità di SalernoVia Giovanni Paolo II 13284084Fisciano (SA)Italy
| | - Costantino Mauro
- Dipartimento di Fisica “E.R. Caianiello” and CNR‐SPIN SalernoUniversità di SalernoVia Giovanni Paolo II 13284084Fisciano (SA)Italy
| | - Felix Lang
- Helmholtz‐Zentrum Berlin für Materialien und Energie GmbHInstitut für Silizium PhotovoltaikKekuléstr. 512489BerlinGermany
| | - Steve Albrecht
- Helmholtz‐Zentrum Berlin für Materialien und Energie GmbHInstitut für Silizium PhotovoltaikKekuléstr. 512489BerlinGermany
| | - Bernd Rech
- Helmholtz‐Zentrum Berlin für Materialien und Energie GmbHInstitut für Silizium PhotovoltaikKekuléstr. 512489BerlinGermany
| | - Sergio Pagano
- Dipartimento di Fisica “E.R. Caianiello” and CNR‐SPIN SalernoUniversità di SalernoVia Giovanni Paolo II 13284084Fisciano (SA)Italy
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Probing Temperature-Dependent Recombination Kinetics in Polymer:Fullerene Solar Cells by Electric Noise Spectroscopy. ENERGIES 2017. [DOI: 10.3390/en10101490] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Dobrovolsky A, Merdasa A, Unger EL, Yartsev A, Scheblykin IG. Defect-induced local variation of crystal phase transition temperature in metal-halide perovskites. Nat Commun 2017; 8:34. [PMID: 28652597 PMCID: PMC5484711 DOI: 10.1038/s41467-017-00058-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 04/24/2017] [Accepted: 04/28/2017] [Indexed: 11/21/2022] Open
Abstract
Solution-processed organometal halide perovskites are hybrid crystalline semiconductors highly interesting for low-cost and efficient optoelectronics. Their properties are dependent on the crystal structure. Literature shows a variety of crystal phase transition temperatures and often a spread of the transition over tens of degrees Kelvin. We explain this inconsistency by demonstrating that the temperature of the tetragonal-to-orthorhombic phase transition in methylammonium lead triiodide depends on the concentration and nature of local defects. Phase transition in individual nanowires was studied by photoluminescence microspectroscopy and super-resolution imaging. We propose that upon cooling from 160 to 140 K, domains of the crystal containing fewer defects stay in the tetragonal phase longer than highly defected domains that readily transform to the high bandgap orthorhombic phase at higher temperatures. The existence of relatively pure tetragonal domains during the phase transition leads to drastic photoluminescence enhancement, which is inhomogeneously distributed across perovskite microcrystals. Understanding crystal phase transition in materials is of fundamental importance. Using luminescence spectroscopy and super-resolution imaging, Dobrovolsky et al. study the transition from the tetragonal to orthorhombic crystal phase in methylammonium lead triiodide nanowires at low temperature.
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Affiliation(s)
| | - Aboma Merdasa
- Chemical Physics and Nano Lund, Lund University, Box 124, Lund, 22100, Sweden
| | - Eva L Unger
- Chemical Physics and Nano Lund, Lund University, Box 124, Lund, 22100, Sweden.,Helmholtz-Zentrum Berlin GmbH, Institut fur Silizium Photovoltaik, Kekuléstrasse 5, Berlin, 12489, Germany
| | - Arkady Yartsev
- Chemical Physics and Nano Lund, Lund University, Box 124, Lund, 22100, Sweden
| | - Ivan G Scheblykin
- Chemical Physics and Nano Lund, Lund University, Box 124, Lund, 22100, Sweden.
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