Author
Wei Huang
Bio: Wei Huang is an academic researcher from Institut national de la recherche scientifique. The author has contributed to research in topics: Thin film & Pulsed laser deposition. The author has an hindex of 8, co-authored 9 publications receiving 704 citations.
Papers
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TL;DR: Tuning the bandgap of multiferroic solar cells made from Bi2FeCrO6 is achieved by cationic ordering and is shown to dramatically improve their performance as discussed by the authors.
Abstract: Tuning the bandgap of multiferroic solar cells made from Bi2FeCrO6 is achieved by cationic ordering and is shown to dramatically improve their performance.
617 citations
TL;DR: The findings validate the use of multiferroic Bi(2) FeCrO(6) thin films as photocathode materials, and prove that the manipulation of internal fields through polarization in ferroelectric materials is a promising strategy for the design of improved photoelectrodes and smart devices for solar energy conversion.
Abstract: Ferroelectric materials have been studied increasingly for solar energy conversion technologies due to the efficient charge separation driven by the polarization induced internal electric field. However, their insufficient conversion efficiency is still a major challenge. Here, a photocathode material of epitaxial double perovskite Bi(2) FeCrO(6) multiferroic thin film is reported with a suitable conduction band position and small bandgap (1.9-2.1 eV), for visible-light-driven reduction of water to hydrogen. Photoelectrochemical measurements show that the highest photocurrent density up to -1.02 mA cm(-2) at a potential of -0.97 V versus reversible hydrogen electrode is obtained in p-type Bi(2) FeCrO(6) thin film photocathode grown on SrTiO(3) substrate under AM 1.5G simulated sunlight. In addition, a twofold enhancement of photocurrent density is obtained after negatively poling the Bi(2) FeCrO(6) thin film, as a result of modulation of the band structure by suitable control of the internal electric field gradient originating from the ferroelectric polarization in the Bi(2) FeCrO(6) films. The findings validate the use of multiferroic Bi(2) FeCrO(6) thin films as photocathode materials, and also prove that the manipulation of internal fields through polarization in ferroelectric materials is a promising strategy for the design of improved photoelectrodes and smart devices for solar energy conversion.
73 citations
TL;DR: In this article, an array of ferroelectric nanowires for photoelectrochemical (PEC) hydrogen production was demonstrated. And the poling bias was manipulated to tune the photocurrent density in the range from ca. 0.7 − 11.5 μA·cm−2 (at 0 −V vs. Ag/AgCl) under irradiation of air mass 1.5 global (AM 1 −1.5 G) full sunlight at 100 mW/cm2, while the onset potential switches from −0.32 to − 0.46
63 citations
TL;DR: In this paper, a double-perovskite multiferroic Bi2FeCrO6 thin film was used as intrinsic absorber, sandwiched between hole and electron-transporting layers, a p-type NiO and an n-type Nb-doped SrTiO3 semiconductor, respectively.
Abstract: Photovoltaic devices made of ferroelectric films are being widely studied, due to their efficient charge separation driven by the internal polarization as well as above-bandgap generated photovoltages. These features may enable power conversion efficiencies (PCE) exceeding the Shockley–Queisser limit, which characterizes conventional semiconductor-based solar cells. However, improving the PCE of such devices is still a challenge, mainly due to the weak charge transport and collection induced by the recombination of photocarriers. Here, we fabricated p–i–n heterojunction devices based on double-perovskite multiferroic Bi2FeCrO6 thin films. The latter act as intrinsic absorbers, sandwiched between hole- and electron-transporting layers, a p-type NiO and an n-type Nb-doped SrTiO3 semiconductor, respectively. Under 1 sun illumination, the optimized p–i–n device yields an open-circuit voltage of 0.53 V and a short-circuit current density of 8.0 mA cm−2, leading to a PCE of ca. 2.0%, a four-fold enhancement compared to that of the i–n device architecture.
49 citations
TL;DR: The fabrication of photoelectrodes based on n-type ferroelectric (FE) semiconductor BFCO heterojunctions coated with p-type transparent conducting oxides (TCOs) by pulsed laser deposition and the successful achievement of p-TCOs/n-FE heterojunction photoanodes that are able to sustain water oxidation that is stable for many hours are revealed.
Abstract: The photoelectric properties of multiferroic double-perovskite Bi2FeCrO6 (BFCO), such as above-band gap photovoltages, switchable photocurrents, and bulk photovoltaic effects, have recently been explored for potential applications in solar technology. Here, we report the fabrication of photoelectrodes based on n-type ferroelectric (FE) semiconductor BFCO heterojunctions coated with p-type transparent conducting oxides (TCOs) by pulsed laser deposition and their application for photoelectrochemical (PEC) water oxidation. The photocatalytic properties of the bare BFCO photoanodes can be improved by controlling the FE polarization state. However, the charge recombination as well as the limited charge transfer kinetics in the photoanode/electrolyte cause major energy loss and thus hinder the PEC performance. We show that this problem may be addressed by the deposition of an ultrathin p-type NiO layer on the photoanode to enhance the charge transport kinetics and reduce charge recombination at surface-trapped ...
37 citations
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TL;DR: The homologous 2D halide perovskites define a promising class of stable and efficient light-absorbing materials for solid-state photovoltaics and other applications.
Abstract: We report on the fabrication and properties of the semiconducting 2D (CH3(CH2)3NH3)2(CH3NH3)n–1PbnI3n+1 (n = 1, 2, 3, and 4) perovskite thin films. The band gaps of the series decrease with increasing n values, from 2.24 eV (CH3(CH2)3NH3)2PbI4 (n = 1) to 1.52 eV CH3NH3PbI3 (n = ∞). The compounds exhibit strong light absorption in the visible region, accompanied by strong photoluminescence at room temperature, rendering them promising light absorbers for photovoltaic applications. Moreover, we find that thin films of the semi-2D perovskites display an ultrahigh surface coverage as a result of the unusual film self-assembly that orients the [PbnI3n+1]− layers perpendicular to the substrates. We have successfully implemented this 2D perovskite family in solid-state solar cells, and obtained an initial power conversion efficiency of 4.02%, featuring an open-circuit voltage (Voc) of 929 mV and a short-circuit current density (Jsc) of 9.42 mA/cm2 from the n = 3 compound. This result is even more encouraging con...
1,589 citations
TL;DR: An insight into the analogies, state-of-the-art technologies, concepts, and prospects under the umbrella of perovskite materials (both inorganic-organic hybrid halideperovskites and ferroelectric perovkites) for future multifunctional energy conversion and storage devices is provided.
Abstract: An insight into the analogies, state-of-the-art technologies, concepts, and prospects under the umbrella of perovskite materials (both inorganic-organic hybrid halide perovskites and ferroelectric perovskites) for future multifunctional energy conversion and storage devices is provided. Often, these are considered entirely different branches of research; however, considering them simultaneously and holistically can provide several new opportunities. Recent advancements have highlighted the potential of hybrid perovskites for high-efficiency solar cells. The intrinsic polar properties of these materials, including the potential for ferroelectricity, provide additional possibilities for simultaneously exploiting several energy conversion mechanisms such as the piezoelectric, pyroelectric, and thermoelectric effect and electrical energy storage. The presence of these phenomena can support the performance of perovskite solar cells. The energy conversion using these effects (piezo-, pyro-, and thermoelectric effect) can also be enhanced by a change in the light intensity. Thus, there lies a range of possibilities for tuning the structural, electronic, optical, and magnetic properties of perovskites to simultaneously harvest energy using more than one mechanism to realize an improved efficiency. This requires a basic understanding of concepts, mechanisms, corresponding material properties, and the underlying physics involved with these effects.
1,015 citations
TL;DR: Bismuth perovskites have very promising properties for further development in solar cells and a power conversion efficiency of over 1% is obtained.
Abstract: Low-toxic bismuth-based perovskites are prepared for the possible replacement of lead perovskite in solar cells. The perovskites have a hexagonal crystalline phase and light absorption in the visible region. A power conversion efficiency of over 1% is obtained for a solar cell with Cs3 Bi2 I9 perovskite, and it is concluded that bismuth perovskites have very promising properties for further development in solar cells.
884 citations
TL;DR: In this paper, a new family of Pb-free inorganic halide double perovskites based on bismuth or antimony and noble metals was proposed, which exhibits tunable band gaps in the visible range and low carrier effective masses.
Abstract: Lead-based halide perovskites are emerging as the most promising class of materials for next-generation optoelectronics; however, despite the enormous success of lead-halide perovskite solar cells, the issues of stability and toxicity are yet to be resolved. Here we report on the computational design and the experimental synthesis of a new family of Pb-free inorganic halide double perovskites based on bismuth or antimony and noble metals. Using first-principles calculations we show that this hitherto unknown family of perovskites exhibits very promising optoelectronic properties, such as tunable band gaps in the visible range and low carrier effective masses. Furthermore, we successfully synthesize the double perovskite Cs2BiAgCl6, perform structural refinement using single-crystal X-ray diffraction, and characterize its optical properties via optical absorption and photoluminescence measurements. This new perovskite belongs to the Fm3m space group and consists of BiCl6 and AgCl6 octahedra alternating in...
678 citations
TL;DR: In this paper, the authors propose that defect tolerance emerges from fundamental electronic-structure properties, including the orbital character of the conduction and valence band extrema, the chargecarrier effective masses, and the static dielectric constant.
Abstract: The emergence of methyl-ammonium lead halide (MAPbX3) perovskites motivates the identification of unique properties giving rise to exceptional bulk transport properties, and identifying future materials with similar properties. Here, we propose that this “defect tolerance” emerges from fundamental electronic-structure properties, including the orbital character of the conduction and valence band extrema, the chargecarrier effective masses, and the static dielectric constant. We use MaterialsProject.org searches and detailed electronic-structure calculations to demonstrate these properties in other materials than MAPbX3. This framework of materials discovery may be applied more broadly, to accelerate discovery of new semiconductors based on emerging understanding of recent successes.
621 citations