Switchable Photovoltaic Effects in Hexagonal Manganite Thin Films Having Narrow Band Gaps

Han, Hyeon; Song, Seungwoo; Lee, June Ho; Kim, Kun Joong; Kim, Guan‐Woo; Park, Jin Young; Jang, Hyun M.

doi:10.1021/acs.chemmater.5b03408

Cited by 76 publications

(55 citation statements)

References 61 publications

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“…Recently, the ferroelectric photovoltaic (FPV) effect observed in inorganic perovskite materials has attracted extensive research interests, due to its high potential in obtaining solar cells with good stability and high-energy conversion efficiency. [1][2][3] Unlike the p-n junction interfacial photovoltaic (PV) effect in traditional solar cells, the photogenerated carries in FPV materials can be better separated by the polarizationinduced internal electric field existing in the whole-bulk region of ferroelectric materials. 4,5 In addition, the photocurrent direction can be switched by reversing the polarization of ferroelectric materials via an applied electric field.…”

Section: Introductionmentioning

confidence: 99%

Greatly enhanced photocurrent in inorganic perovskite [KNbO₃]_0.9[BaNi_0.5Nb_0.5O_3‐σ]_0.1 ferroelectric thin‐film solar cell

et al. 2018

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Inorganic perovskite [KNbO3]0.9[BaNi0.5Nb0.5O3‐σ]0.1 (KBNNO) ferroelectric thin films with narrow band gap (1.83 eV) and high room‐temperature remnant polarization (Pr = 0.54 μC/cm2) was grown successfully on the Pt(111)/Ti/SiO2/Si(100) substrates by pulsed laser deposition. Ferroelectric solar cells with a basic structure of ITO/KBNNO/Pt were further prepared based on these thin films, which exhibited obvious external‐poling dependent photovoltaic effects. When the devices were negatively poled, the short‐circuit current and open‐circuit voltage were both significantly higher than those of the devices poled positively. This is attributed to enhanced charge separation under the depolarization field induced by the negative poling, which is superimposed with the built‐in field induced by the Schottky barriers at the interfaces between KBNNO and the two electrodes. When a poling voltage of ‐1 V was applied, the device showed a short‐circuit current as high as 27.3 μA/cm2, which was by two orders of magnitude larger than that of the KBNNO thick‐film (20 μm) devices reported previously. This work may inspire further exploration for lead‐free inorganic perovskite ferroelectric photovoltaic devices.

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Section: Introductionmentioning

confidence: 99%

Greatly enhanced photocurrent in inorganic perovskite [KNbO₃]_0.9[BaNi_0.5Nb_0.5O_3‐σ]_0.1 ferroelectric thin‐film solar cell

et al. 2018

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“…H-LuMnO 3 -type multiferroic oxides have been extensively investigated because they exhibit both magnetoelectric [9][10][11] and magnetoelastic effects [12]. erefore, this system is an interesting material for application in ferroelectric photovoltaic devices [13]. Currently, a lot of research studies have been focused on the various forms of these materials, such as powders, nanostructures, bulk, and thin films [11,[14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Stereometric and Fractal Patterns of Spin‐Coated LuMnO₃ Thin Films

Marques

Matos

Romaguera-Barcelay

et al. 2021

Advances in Materials Science and Engineering

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In this paper, we have performed qualitative and quantitative analysis of LuMnO3 thin films surfaces, deposited by spin coating over Pt(111)/TiO2/SiO2/Si substrates, to evaluate their spatial patterns as a function of the film’s sintering temperature. Atomic force microscopy was employed to obtain topographic maps that were extensively analyzed via image processing techniques and mathematical tools. 3D (three-dimensional) topographical images revealed that films sintered at 650°C and 750°C presented the formation of smoother surfaces, while the film sintered at 850°C displayed a rougher surface with a root mean square roughness of ∼2.5 nm. On the other direction, the height distribution of the surface for all films has similar asymmetries and shape, although the film sintered using the highest temperature showed the lower density of rough peaks and a sharper peak shape. The advanced fractal parameters revealed that the film sintered at 850°C is dominated by low spatial frequencies, showing less spatial complexity, higher microtexture homogeneity, and uniform height distribution. These results suggest that the combination of stereometric and fractal parameters can be especially useful for identification of unique topographic spatial patterns in LuMnO3 thin films, helping in their implementation in technological applications, such as photovoltaic solar cells and information magnetic date storage and spintronic devices.

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“…In particular the issue is whether it is possible to tune between these two minima with field and whether the critical field for this, i.e., the coercive field is of a realizable magnitude. [6a,14] As shown in Figure a, the asymmetric Li potential energy profile shows that the γ‐down polar state is preferred without an external electric field. However, when a negative electric field gradually increased to –0.48 eV Å −1 , the electric polarization energy stabilizes the γ‐up state due to the interaction of the dipole with the field.…”

Section: Resultsmentioning

confidence: 99%

Switchable Out‐of‐Plane Polarization in 2D LiAlTe₂

Liu

Sun

Singh

et al. 2019

Adv Elect Materials

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in certain improper ferroelectrics. [3] This is important for the electronic polarizability that plays an important role in this class of materials, and underlies the hyperferroelectric behavior, specifically the resistance to depolarizing field. The key condition is the instability of longitudinal optic modes in addition to active transverse optic instability characteristic of normal ferroelectrics. This provides a mechanism for canceling the depolarizing field. As shown in Figure 1, a number of these hyperferroelectrics adopt a polar stuffed wurtzite structure which is typically formed by an ABC stoichiometry (A, B, and C represent different elements). [4] This mechanism motivates us to extend the range of materials by searching for a different class of covalent-polar compounds, ABC 2 , exemplified by LiAlTe 2 . [5] It provides opportunities for designing switchable devices since it is compatible with substrates such as germanium tellurium (GeTe), which are prototypical phase change memory materials.The ABC 2 ternary compound β-LiAlTe 2 has a layered polar covalent tetrahedral structure, space group, P3m1 (156). [5a] As shown in Figure 1a, this quadruple-layered (QL) crystal is formed by an in-plane covalent bonded AlTe 4 tetrahedral layer with Li atoms located in the distorted trigonal antiprisms, with van der Waals (vdW) bonding between the QL. This vdW bonding suggests that in addition to being polar, such material may be an amenable formation in single QL form as a 2D material. This raises the possibility of having a hyperferroelectric 2D layered material based on the phase with an out-of-plane polarization. In most case, there are two major approaches to obtain polarization in 2D materials: (a) functionalization of nonpolar 2D materials; (b) searching for 2D intrinsic ferroelectric materials. [6] The former strategy uses chemical doping or surface passivation to produce switchable dipoles. [7] The latter approach is to find materials with intrinsic 2D polarization, such as Janus 2D materials. [8] These derivative 2D materials with broken mirror symmetry attracted considerable attention because of their unique properties, such as large piezoelectric effect, Rashba spin splitting, and second-harmonic generation response.

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Switchable Photovoltaic Effects in Hexagonal Manganite Thin Films Having Narrow Band Gaps

Cited by 76 publications

References 61 publications

Greatly enhanced photocurrent in inorganic perovskite [KNbO₃]_0.9[BaNi_0.5Nb_0.5O_3‐σ]_0.1 ferroelectric thin‐film solar cell

Greatly enhanced photocurrent in inorganic perovskite [KNbO₃]_0.9[BaNi_0.5Nb_0.5O_3‐σ]_0.1 ferroelectric thin‐film solar cell

Investigation of Stereometric and Fractal Patterns of Spin‐Coated LuMnO₃ Thin Films

Switchable Out‐of‐Plane Polarization in 2D LiAlTe₂

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Switchable Photovoltaic Effects in Hexagonal Manganite Thin Films Having Narrow Band Gaps

Cited by 76 publications

References 61 publications

Greatly enhanced photocurrent in inorganic perovskite [KNbO3]0.9[BaNi0.5Nb0.5O3‐σ]0.1 ferroelectric thin‐film solar cell

Greatly enhanced photocurrent in inorganic perovskite [KNbO3]0.9[BaNi0.5Nb0.5O3‐σ]0.1 ferroelectric thin‐film solar cell

Investigation of Stereometric and Fractal Patterns of Spin‐Coated LuMnO3 Thin Films

Switchable Out‐of‐Plane Polarization in 2D LiAlTe2

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Greatly enhanced photocurrent in inorganic perovskite [KNbO₃]_0.9[BaNi_0.5Nb_0.5O_3‐σ]_0.1 ferroelectric thin‐film solar cell

Greatly enhanced photocurrent in inorganic perovskite [KNbO₃]_0.9[BaNi_0.5Nb_0.5O_3‐σ]_0.1 ferroelectric thin‐film solar cell

Investigation of Stereometric and Fractal Patterns of Spin‐Coated LuMnO₃ Thin Films

Switchable Out‐of‐Plane Polarization in 2D LiAlTe₂