scholarly journals Domain and Switching Control of the Bulk Photovoltaic Effect in Epitaxial BiFeO3 Thin Films

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
David S. Knoche ◽  
Yeseul Yun ◽  
Niranjan Ramakrishnegowda ◽  
Lutz Mühlenbein ◽  
Xinye Li ◽  
...  
Keyword(s):  
Electric Fields ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Inversion Symmetry ◽  
Bifeo3 Thin Films ◽  
Piezoelectric Effects ◽  
Angular Dependency ◽  
Polarization Orientation ◽  
Domain Arrangement

Abstract Absence of inversion symmetry is the underlying origin of ferroelectricity, piezoelectricity, and the bulk photovoltaic (BPV) effect, as a result of which they are inextricably linked. However, till now, only the piezoelectric effects (inverse) have been commonly utilized for probing ferroelectric characteristics such as domain arrangements and resultant polarization orientation. The bulk photovoltaic effect, despite sharing same relation with the symmetry as piezoelectricity, has been mostly perceived as an outcome of ferroelectricity and not as a possible analytical method. In this work, we investigate the development of BPV characteristics, i.e. amplitude and angular dependency of short-circuit current, as the ferroelastic domain arrangement is varied by applying electric fields in planar devices of BiFeO3 films. A rather sensitive co-dependency was observed from measurements on sample with ordered and disordered domain arrangements. Analysis of the photovoltaic response manifested in a mathematical model to estimate the proportion of switched and un-switched regions. The results unravel the potential utility of BPV effect to trace the orientation of the polarization vectors (direction and amplitude) in areas much larger than that can be accommodated in probe-based techniques.

scholarly journals Photocurrent density and electrical properties of Bi0.5Na0.5TiO3-BaNi0.5Nb0.5O3 ceramics

2021 ◽  
Author(s):  
Mingqiang Zhong ◽  
Qin Feng ◽  
Changlai Yuan ◽  
Xiao Liu ◽  
Baohua Zhu ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Photocurrent Density ◽  
Open Circuit ◽  
Light Conditions ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray

AbstractIn this work, the (1−x)Bi0.5Na0.5TiO3-xBaNi0.5Nb0.5O3 (BNT-BNN; 0.00 ⩽ x ⩽ 0.20) ceramics were prepared via a high-temperature solid-state method. The crystalline structures, photovoltaic effect, and electrical properties of the ceramics were investigated. According to X-ray diffraction, the system shows a single perovskite structure. The samples show the normal ferroelectric loops. With the increase of BNN content, the remnant polarization (Pr) and coercive field (Ec) decrease gradually. The optical band gap of the samples narrows from 3.10 to 2.27 eV. The conductive species of grains and grain boundaries in the ceramics are ascribed to the double ionized oxygen vacancies. The open-circuit voltage (Voc) of ∼15.7 V and short-circuit current (Jsc) of ∼1450 nA/cm2 are obtained in the 0.95BNT-0.05BNN ceramic under 1 sun illumination (AM1.5G, 100 mW/cm2). A larger Voc of 23 V and a higher Jsc of 5500 nA/cm2 are achieved at the poling field of 60 kV/cm under the same light conditions. The study shows this system has great application prospects in the photovoltaic field.

Enhancement of Oxygen Vacancies Induced Photovoltaic Effects in Bi0.9La0.1FeO3 Thin Films

2015 ◽  
Vol 815 ◽  
pp. 176-182 ◽  
Author(s):  
Rong Li Gao ◽  
Chun Lin Fu ◽  
Wei Cai ◽  
Gang Chen ◽  
Xiao Ling Deng ◽  
...  
Keyword(s):  
Thin Films ◽  
Oxygen Vacancies ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Ferroelectric Films ◽  
Electric Pulses ◽  
Photovoltaic Effects ◽  
Drift Current ◽  
Polarization Orientation ◽  
And Diffusion

The photovoltaic effect in Ag/Bi0.9La0.1FeO3/La0.7Sr0.3MnO3heterostructures was investigated and the short circuit photocurrent was found to be strongly dependent on the polarization orientation and oxygen vacancies (VOs) distribution. The photocurrent direction was switched accompanying polarization switching. Besides, according to manipulate theVOsaccumulated at either the Ag/Bi0.9La0.1FeO3or the Bi0.9La0.1FeO3/La0.7Sr0.3MnO3interface by electric pulses, obvious enhancement of photovoltaic effects was obtained. These results can be explained well using the concepts of drift current and diffusion current controlled by the combination of oxygen vacancies and polarization. This work provides deep insights into the nature of photovoltaic effects in ferroelectric films, and will facilitate the advanced design devices combining spintronic, electronic, and optical functionalities.

Photoelectric Characteristics of Rare Earth Element Er Doped Molybdenum Selenide Thin Films

2020 ◽  
Vol 15 (3) ◽  
pp. 384-388 ◽  
Author(s):  
Xiying Ma ◽  
Cheng Xu ◽  
Qiang Zhang ◽  
Weilin Shi
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Photoelectric Characteristics ◽  
Molybdenum Selenide

The preparation and the photoelectric characteristics of molybdenum selenide (MoSe2) films doped with the rare earth element Er3+ are presented herein. The surface mororphology, light absorption and emission of the undoped and Er3+ doped MoSe2 thin films were analyzed, we found that the Er3+ doped MoSe2 films exhibited more crystalline, and their mobility and conductivity were enhanced by about one order higher relative to that of the pure sample. Also, the optical absorptivity and luminous intensity of Er3+ doped MoSe2 were also enhanced by two times than that of the pure MoSe2. In addition, the photovoltaic effect of the Er3+-doped MoSe2 films increased significantly. The short-circuit current increased almost ten-fold, and the open-circuit voltage was enhanced four-fold. These results show that the Er3+ ions not only enhanced the conductivity, but also improved the optical properties of the films. The Er3+ doped MoSe2 may be applied to make sensitive light emitting devices and detectors.

Photoelectric Effects at Domain Walls

Domain Walls ◽  
2020 ◽  
pp. 199-216
Author(s):  
M.-M. Yang ◽  
M. Alexe
Keyword(s):  
Domain Walls ◽  
Chemical Potential ◽  
Film Growth ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Domain Wall Motion ◽  
Short Circuit Current ◽  
Ferroelectric Materials ◽  
Visible Range ◽  
Art Research

This chapter reviews the history and the state-of-the-art research of the ferroelectric photovoltaic effect, in particular the role of DWs. Over the last decade, the field of ferroelectric photovoltaic effect has been experiencing a significant revival. Ferroelectrics can spontaneously generate a short-circuit current under uniform illumination owing to the asymmetric momentum distribution of the nonequilibrium photo-excited carriers in the k-space, termed the bulk photovoltaic effect. In contrast to the conventional photovoltaic effect based on a gradient of the chemical potential, the ferroelectric photovoltaic effect exhibits distinctive features. Although the solar energy harvesting based on ferroelectric materials suffers a low power conversion efficiency due to their poor light absorption in the visible range and high resistance, the progress in oxide thin film growth has significantly promoted the efficiency of ferroelectric solar cells in recent years. Meanwhile, the coupling of light with intrinsic degrees of freedom offers a fertile and rich playground to explore the new functionalities of (multi-)ferroelectrics and to develop related applications. In this regard, light-induced reversible ferroelectric switching and domain wall motion have been recently achieved.

Photovoltaic Effect in the Anisotype GaSe-InSe Heterojunctions Under Pressure

2005 ◽  
Vol 865 ◽  
Author(s):  
S.I. Drapak ◽  
M.O. Vorobets ◽  
Z.D. Kovalyuk
Keyword(s):  
Open Circuit Voltage ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Photoconversion Efficiency ◽  
Mechanical Pressure

AbstractThe influence of mechanical pressure along the direction across the interface of n-InSe-p-GaSe heterojunctions on saturation photo-e.m.f. and short-circuit current is investigated. It is shown that at the InSe/GaSe optical contacts subjected to a pressure P = 35-40 kPa an increase of the open-circuit voltage nearly twice and short-circuit current more than by a factor of five in comparison to the initial samples takes place. It makes possible to predict a possibility of considerable increasing photoconversion efficiency of such structures.

scholarly journals Characterising Exciton Generation in Bulk-Heterojunction Organic Solar Cells

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 209
Author(s):  
Kiran Sreedhar Ram ◽  
Hooman Mehdizadeh-Rad ◽  
David Ompong ◽  
Daniel Setsoafia ◽  
Jai Singh
Keyword(s):  
Solar Cells ◽  
Electric Fields ◽  
Active Layer ◽  
Organic Solar Cells ◽  
Bulk Heterojunction ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Short Circuit Current ◽  
Photon Absorption ◽  
Active Layer Thickness

In this paper, characterisation of exciton generation is carried out in three bulk-heterojunction organic solar cells (BHJ OSCs)—OSC1: an inverted non-fullerene (NF) BHJ OSC; OSC2: a conventional NF BHJ OSC; and OSC3: a conventional fullerene BHJ OSC. It is found that the overlap of the regions of strong constructive interference of incident and reflected electric fields of electromagnetic waves and those of high photon absorption within the active layer depends on the active layer thickness. An optimal thickness of the active layer can thus be obtained at which this overlap is maximum. We have simulated the rates of total exciton generation and position dependent exciton generation within the active layer as a function of the thicknesses of all the layers in all three OSCs and optimised their structures. Based on our simulated results, the inverted NF BHJ OSC1 is found to have better short circuit current density which may lead to better photovoltaic performance than the other two. It is expected that the results of this paper may provide guidance in fabricating highly efficient and cost effective BHJ OSCs.

The investigation of the acousto-photovoltaic effect in single crystals TlIn1−xGaxSe2

2020 ◽  
pp. 2150011
Author(s):  
E. M. Gojayev ◽  
G. N. Mamedova ◽  
S. S. Osmanova ◽  
Sh. M. Mehdiyeva ◽  
S. H. Jabarov
Keyword(s):  
Single Crystals ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Partial Substitution ◽  
Tetragonal Symmetry ◽  
Sound Waves ◽  
Unit Cells ◽  
Zone Recrystallization ◽  
First Time

In this work, TlIn[Formula: see text]Ga[Formula: see text]Se2 single crystals were grown by zone recrystallization methods and their X-ray phase analysis was performed. The lattice parameters were determined and it was found that crystals based on the original TlIn[Formula: see text]Ga[Formula: see text]Se2 compound crystallized in the same tetragonal symmetry, the space group [Formula: see text]. It was revealed that with partial substitution of indium atoms by gallium atoms in the TlIn[Formula: see text]Ga[Formula: see text]Se2 lattice, the parameters of unit cells change according to the additivity law. First time it was found that with the simultaneous influence of electromagnetic and sound waves, an electromotive force (e.m.f.) occurs or short circuit current. The studies were carried out in the frequency range of electromagnetic radiation of 50–143 kHz. It was revealed that when the investigated crystals were irradiated with magnetic radiation in the absence of sound waves, there was no e.m.f. on the electrodes as well as memory when exposed only to sound. Based on the existing theoretical information, the nature of the revealed single crystal of the acousto-photovoltaic effect was explained.

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