Search query: High photocurrent densities in Bi0.5Na0.5TiO3 ferroelectric semiconductors

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abstract: Abstract A new solid solution of (1 x) Bi0.5Na0.5TiO3 x BaCo0.5Nb0.5O3 (BNT BCN; x 0, 0.05, 0.10, 0.15, 0.20) were fabricated via the solid state route. All the samples reflect single perovskite structure and normal ferroelectric behavior. The lowest band gap ~0.92 eV of Bi0.5Na0.5TiO3 doped with BaCo0.5Nb0.5O3 is achieved. Under simulated standard sunlight, the short circuit photocurrent (Jsc) of ~34.15 uA/cm2 and open circuit photovoltage (Voc) of ~10.24 V in the 0.90BNT 0.10BCN ceramic after the polarization of 60 kV/cm are obtained, which is much higher than that of the most perovskite oxide ceramics. The power conversion efficiency of the 0.90BNT 0.10BCN is about 0.17% The current system shows considerable advantages in the field of high stability photovoltaic devices.
author_names: Ming-qiang Zhong

Changlai Yuan

Xiao Liu

Baohua Zhu

Liufang Meng

Changrong Zhou

Fei Liu

Jiwen Xu

Jiang Wang

Guanghui Rao
title: High photocurrent densities in Bi0.5Na0.5TiO3 ferroelectric semiconductors
year: 2021

abstract: This report describes the sintering and ferroelectric characteristic of 0.76 Bi0.5Na0.5TiO3 (BNT) 0.26SrTiO3 (ST) with CuO addition, synthesized by using a solid state reaction. The XRD, microstructure, and density results reveal that Cu element reduces the sintering temperature from 1150 to 1000 degC. In dielectric study, CuO addition induces the increase of relaxation behavior for 26ST ceramic in the high temperature regime. In the low temperature regime 150 degC) the Cu doping to 26ST accelerates the degree in freezing of dipole, presumably due to the interaction between A site vacancy and nanodomain boundaries. The electromechanical properties of 26ST ceramics with CuO doping show a significant decay in frequency dependence of polarization and strain, which might be related to the formation of A site cation vacancy.
author_names: Mohsin Saleem

In-sung Kim

Min-soo Kim

Bo-Kun Koo

Soon-jong Jeong
title: Large signal electrical property of CuO doped of a Bi0.5Na0.5TiO3 SrTiO3
venue: Journal of Electroceramics
year: 2017

abstract: Abstract The use of Bi0.5Na0.5TiO3 (BNT) based materials is largely limited by their inherent thermal depolarization where the piezoelectric properties decreases remarkably. It is intractable to simultaneously realize high piezoelectric properties and reliable thermal stability over the required operating range in BNT based systems. Here, we demonstrated an alternative design method to commonly applied chemical doping or substituting to tailor the functional properties, by judiciously forming 0 3 type composites of ferroelectric 0.83(Bi0.5Na0.5)TiO3 0.17(Bi0.5K0.5)TiO3 with semiconductor ZnO inclusions (BNT BKT:ZnO) to balance the aforementioned paradox. In BNT BKT:0.1ZnO composite, we achieved distinguished comprehensive performance: high thermal stability of piezoelectric coefficient d33 (maintaining 73% of the initial value at 120 degC) good fatigue characteristic (deterioration of 8% up to 105 cycles in the field induced strain) and relatively large room temperature d33 of 109 pC/N. The mechanism for the enhanced fatigue behavior was mainly ascribed to the lower defect density arising from the lower oxygen vacancy concentration in composites as compared to pure BNT BKT. Most interestingly, hardening of piezoelectric properties usually produced by doping with lower valence elements, was realized in composites, as characterized by nearly two fold increase in mechanical quality factor (Qm) in comparison to BNT BKT. Our research not only offers a feasible paradigm for tailoring functional properties of BNT based materials though composite engineering, but also inspires further works to benefit a wide range of functionalities in other ferroelectric materials.
author_names: Wangfeng Bai

Leijie Wang

Peng Zheng

Fei Wen

Lili Li

Zhen-guo Ji

Jiwei Zhai
title: Enhanced thermal stability, hardening of piezoelectric property, and mediated electromechanical response in (Bi0.5Na0.5)TiO3 based piezoceramics via composite approach
year: 2018

abstract: Abstract A lead free solid solution of two ferroelectrics, bismuth sodium titanate and barium titanate, of a composition 0.96(Bi0.5Na0.5TiO3) 0.04(BaTiO3) (termed as BNT BT 4) was prepared by a standard low cost ceramic technology. The phase analysis of the solid solution, carried out using X ray diffraction pattern, shows a major tetragonal phase and a minor impurity phase at room temperature. The surface morphology of the prepared system showed the formation of the high density sample. The phonon mode statistics, width location and intensity of the peaks were analyzed by Raman spectroscopy. The temperature frequency dependence of dielectric parameters (permittivity and tangent loss) and AC conductivity were analyzed. The apparent activation energy of BNT BT 4 was evaluated with help of AC conductivity data. The effect of grain on the capacitive and resistive properties has been studied using an impedance spectroscopy technique. The decrease in the value of grain resistance on rising temperature shows the semiconductor or negative temperature coefficient behavior of the material. Based on an analysis of complex modulus spectrum, the conduction mechanism in the material has been suggested. As BNT BT 4 shows a remarkable temperature independent relative dielectric properties and low tangent loss, it is a potential candidate for devices.
author_names: Sugato Hajra

Sushrisangita Sahoo

Rutuparna Das

R N P Choudhary
title: Structural, dielectric and impedance characteristics of (Bi0.5Na0.5)TiO3 BaTiO3 electronic system
year: 2018

abstract: Owing to polarization driven efficient charge carrier separation, ferroelectric semiconductors with narrow band gaps ~1.3 eV) can constitute an ideal active layer for photovoltaics, as demonstrated in recent studies on lead halide perovskite solar cells. In this study, antiperovskite oxides with a composition of Ba4Pn2O (Pn=As or Sb) are proposed as promising candidates for high performance ferroelectric photovoltaics. Using the density functional theory (DFT) calculations, it is revealed that Ba4Pn2O exhibits moderate macroscopic polarization enough for charge carrier separation. Moreover, they are predicted to have direct band gaps close to the optimal Shockley Queisser value. By investigating optical absorption coefficients and resulting short circuit currents, it is demonstrated that a very thin layer of Ba4Pn2O can yield large photocurrents. The effective masses of charge carriers in Ba4Pn2O are found to be fairly small 0.2me) implying facile extraction of photocarriers. The favorable simulation results along with the confirmed synthesizability of the materials strongly suggest that Ba4Pn2O will be an active layer suitable for photovoltaics.
author_names: Youngho Kang

Seungwu Han
title: Antiperovskite oxides as promising candidates for high performance ferroelectric photovoltaics: First principles investigation on Ba4As2O and Ba4Sb2O.
venue: ACS applied materials interfaces
year: 2020

abstract: Exploiting spontaneous polarization of ferroelectric materials to achieve high charge separation efficiency is an intriguing but challenging research topic in solar energy conversion. This work shows that loading high work function RuO2 cocatalyst on BiFeO3 (BFO) nanoparticles enhances the intrinsic ferroelectric polarization by efficient screening of charges to RuO2 via RuO2 /BFO heterojunction. This leads to enhancement of the surface photovoltage of RuO2 /BFO single nanoparticles nearly 3 times, the driving force for charge separation and transfer in photocatalytic reactions. Consequently, efficient photocatalytic water oxidation is achieved with quantum efficiency as high as 5.36 at 560 nm, the highest activity reported so far for ferroelectric materials. This work demonstrates that, unlike low photocurrent density in film based ferroelectric devices, high photocatalytic activity could be achieved by regulating the ferroelectric spontaneous polarization using appropriate cocatalyst to enhance driving force for efficient separation and transfer of photogenerated charges in particulate ferroelectric semiconductor materials.
author_names: Jafar H Shah

Biaohong Huang

Ahmed Mahmoud Idris

Yong Liu

Anum Shahid Malik

Weijin Hu

Zhidong Zhang

Hongxian Han

Can Li
title: Regulation of Ferroelectric Polarization to Achieve Efficient Charge Separation and Transfer in Particulate RuO2 /BiFeO3 for High Photocatalytic Water Oxidation Activity.
venue: Small
year: 2020

abstract: Ferroelectric materials, equipping a striking bulk photovoltaic effect (BPVE) have shown great potential for the next generation photovoltaic non volatile memories. However, further applications of conventional ferroelectric materials are hindered by their poor performance. The family of hybrid perovskite ferroelectrics combining fascinating polarization and striking semiconducting properties presents significant possibilities. Herein, through a functional unit transmutation strategy, a fatigue free layered hybrid perovskite ferroelectric (C 6 H 5 CH 2 NH 3 2 CsPb 2 Br 7 BCPB has been developed, which demonstrates stable spontaneous polarization P s of 6.5 mC/cm 2 and high Curie temperature up to 425 K. Meanwhile, BCPB shows splendid BPVE properties with noticeable zero bias photocurrent density (5 mA/cm 2 and high on/off switching ratio of current (over 3x10 5 these merits even overmatch the most known ferroelectric semiconductor BiFeO 3 Particularly, the unique structure with self regulated net electrical charged layers gives rise to the fatigue free feature of P s and BPVE (no significant fatigue after 10 8 polarity switching cycles) promoting the potential applications of BCPB in photovoltaic non volatile memories. As a pioneering work, it offers an efficient approach for exploring fatigue free semiconducting ferroelectrics as well as excavates their further applications in next generation electronic devices.
author_names: Yunpeng Yao

Yunyan Peng

Lina Li

Xinyuan Zhang

Xitao Liu

Maochun Hong

Junhua Luo
title: Exploring a Fatigue Free Layered Hybrid Perovskite Ferroelectric for Photovoltaic Non Volatile Memories.
venue: Angewandte Chemie
year: 2020

abstract: Two dimensional ferroelectrics is attractive for synaptic device applications because of its low power consumption and amenability to high density device integration. Here, we demonstrate that Tin monosulfide (SnS) films less than 6 nm thick shows optimum performance as semiconductor channel in in plane ferroelectric analogue synaptic device, whereas thicker films have much poorer ferroelectric response due to screening effects by a higher concentration of charge carriers. The SnS ferroelectric device exhibits synaptic behaviors with highly stable room temperature operation, high linearity in potentiation/depression, long retention, and low cycle to cycle/device to device variations. The simulated device based on ferroelectric SnS achieves 92.1 of pattern recognition accuracy in artificial neural network simulation. By switching the ferroelectric domains partially, multi level conductance states and conductance ratio can be obtained, achieving high pattern recognition accuracy.
author_names: Ki Chang Kwon

Yishu Zhang

Lianzhou Wang

Wei Yu

Xiaojie Wang

In-Hyeok Park

Hwa Seob Choi

Teng Ma

Ziyu Zhu

Bingbing Tian

Chenliang Su

Kian Ping Loh
title: In Plane Ferroelectric Tin Monosulfide and Its Application in Ferroelectric Analog Synaptic Device.
venue: ACS nano
year: 2020

abstract: The hybrid organic inorganic perovskites have been considered as promising candidates for high performance photodetectors. However, how to fabricate self powered broadband perovskite photodetectors with tunable photoresponse is still challenging. Herein, we design, for the first time, a ferroelectric semiconductor SrTiO3 (STO) and perovskite film hybrid structure based photodetector. After applying appropriate poled bias, the hybrid photodetector exhibits higher responsivity and faster response speed as compared to an unpoled device and a device without an STO ferroelectric interlayer. By optimizing the STO interlayer density, the positively poled photocurrent and response speed are enhanced to 0.956 mA and 0.1 s at zero bias, respectively. The corresponding responsivity is as high as 0.73A/W at a wavelength of 550 nm, which is much higher than that of the device without an STO interlayer. The improved performance is attributed to the fact that positively polarized STO layers can provide a built in potent.
author_names: Fengren Cao

Wei Tian

Meng Wang

Liang Li
title: Polarized Ferroelectric Field Enhanced Self Powered Perovskite Photodetector
year: 2018

abstract: Coupling ferroelectric materials with semiconductor materials can improve the performance of photovoltaic cells. The BaTiO3/TiO2(n) (B/T(n) photoanode of dye sensitized solar cells (DSSCs) is composed of a BaTiO3 core, a high performance and frequently used ferroelectric material, and TiO2 nanoparticles, a common semiconductor material. A hysteresis loop, 105 mC cm 2 remnant polarization and 7 kV cm 1 coercive field of the photoanode demonstrate its ferroelectricity. The short circuit current density (Jsc) of the dye sensitized photoanode after polarization (B/T(n)PD) is superior to that of unpolarized (B/T(n)D) by about 2 mA cm 2, regardless of the direction of polarization. The DSSC based on the B/T(4)PD photoanode exhibits a power conversion efficiency (PCE) of 7.29% and a Jsc of 14.44 mA cm 2. Reflectance spectroscopy, Fourier transform infrared spectroscopy (FTIR) and intensity modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) are carried out to investigate the light absorption, charge injection and separation processes in B/T(n) Spontaneous polarization changes the adsorption state of the dye, which increases the light absorption efficiency, electron injection efficiency, incident light to photocurrent efficiency (IPCE) and Jsc. The discovery reported in this paper provides a method for modulating the interaction of adsorbed molecules with solids by means of electric field changes. This study deepens the understanding of the mechanism of charge transport and photovoltage generation in photovoltaic cells.
author_names: Dongmei Xie

Yuan Lin

Nianqing Fu

Pin Ma

Xiaowen Zhou
title: Changes of the dye adsorption state induced by ferroelectric polarization to improve photoelectric performance
year: 2018