| 1. |
- Ibupoto, Zafar, et al.
(author)
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MoSx@NiO Composite Nanostructures : An Advanced Nonprecious Catalyst for Hydrogen Evolution Reaction in Alkaline Media
- 2019
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In: Advanced Functional Materials. - : John Wiley & Sons. - 1616-301X .- 1616-3028. ; 29:7
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Journal article (peer-reviewed)abstract
- The design of the earth‐abundant, nonprecious, efficient, and stable electrocatalysts for efficient hydrogen evolution reaction (HER) in alkaline media is a hot research topic in the field of renewable energies. A heterostructured system composed of MoSx deposited on NiO nanostructures (MoSx@NiO) as a robust catalyst for water splitting is proposed here. NiO nanosponges are applied as cocatalyst for MoS2 in alkaline media. Both NiO and MoS2@NiO composites are prepared by a hydrothermal method. The NiO nanostructures exhibit sponge‐like morphology and are completely covered by the sheet‐like MoS2. The NiO and MoS2 exhibit cubic and hexagonal phases, respectively. In the MoSx@NiO composite, the HER experiment in 1 m KOH electrolyte results in a low overpotential (406 mV) to produce 10 mA cm−2 current density. The Tafel slope for that case is 43 mV per decade, which is the lowest ever achieved for MoS2‐based electrocatalyst in alkaline media. The catalyst is highly stable for at least 13 h, with no decrease in the current density. This simple, cost‐effective, and environmentally friendly methodology can pave the way for exploitation of MoSx@NiO composite catalysts not only for water splitting, but also for other applications such as lithium ion batteries, and fuel cells.
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| 2. |
- Lin, Dongxu, et al.
(author)
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Construction of an Iodine Diffusion Barrier Using Network Structure Silicone Resin for Stable Perovskite Solar Cells
- 2021
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In: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 13:7, s. 8138-8146
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Journal article (peer-reviewed)abstract
- Long-term stability of organic-inorganic hybrid perovskite solar cells (PSCs) is inhibited by ion diffusion. Herein, we introduce a thermally stable and hydrophobic silicone resin layer with a network structure as an interfacial layer between the perovskite and the hole-transporting layer ( HTL). Experimental and theoretical investigations confirm that the small Si-O-Si unit in the network forms both Si-I and Pb-O bonds with the perovskite surface, which physically and chemically inhibit the diffusion and self-release of iodine. Besides, the silicone resin layer suppresses the thermal crystallization of spiro-OMeTAD and optimizes the interfacial energy level alignment for hole extraction. The power conversion efficiency (PCE) of a perovskite solar cell with a silicone resin layer is improved to 21.11%. The device maintains more than 90.1% of its original PCE after 1200 h under 85 degrees C thermal stress, 99.6% after 2000 h under RH similar to 55 +/- 5%, and 83% of its original PCE after light soaking in air for 1037 h.
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| 3. |
- Lin, Dongxu, et al.
(author)
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The selection strategy of ammonium-group organic salts in vapor deposited perovskites: From dimension regulation to passivation
- 2021
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In: Nano Energy. - : ELSEVIER. - 2211-2855 .- 2211-3282. ; 84
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Journal article (peer-reviewed)abstract
- Dimension regulation and defect passivation are two key strategies for highly efficient and stable perovskite solar cell. Vapor deposition of perovskite is a toxic-solvent-free method for large-scale fabrication. However, without the assistance of solvent for crystal optimization, effective structural regulation and defect passivation become challenging. Here, detailed investigations on the structural evolution of perovskite thin film are carried out in sequential vapor deposition using mixed-vapor (R-NH3I/MAI). Correlation between electron donating ability of R-NH3I (BAI, PEAI, PMAI and ALI) molecule and the way of structural transition is established. It is found that RNH3I with stronger electron-donating ability promoted the phase transition from three-dimensional (3D) to twodimensional (2D) perovskite. Typically, the n value from 1 to 5 can be tuned by reaction time or component control using BAI with the strongest electron donating ability. R-NH3I with weak electron-donating ability suppresses the 3D to 2D transition, but enhances the defect passivation effect. The ALI with the weakest electron donating ability shows the best passivation effect, leading to the best device performance than that of the control 3D device, with PCE of 18.23% (0.045 cm2) and 15.48% (1 cm2) and the significantly improved stability. This study provides the evidence that the concept of Lewis acid-base reaction is applicable in vapor deposition, which provides us with the selection guide of R-NH3I molecules for structural design in vapor fabrication of perovskite thin film.
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| 4. |
- Lin, Dongxu, et al.
(author)
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Vapor Deposited Pure alpha-FAPbI(3) Perovskite Solar Cell via Moisture-Induced Phase Transition Strategy
- 2022
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In: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 32:48
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Journal article (peer-reviewed)abstract
- To fabricate stable neat FAPbI(3) perovskite with a pure alpha-phase (pure alpha-FAPbI(3)) is important in the field of photovoltaic commercialization because of its better bandgap than its alloying counterpart with cesium (Cs) or methylammonium (MA) cations. In this work, the first vapor deposited pure alpha-FAPbI(3) thin film solar cell with a power conversion efficiency (PCE) over 20% is achieved by regulating the phase transition process. It is found that under high humidity conditions, a fast phase transition between high-purity alpha- and delta-phase FAPbI(3) can be realized. Moreover, theoretical calculations interestingly reveal a phase transition shortcut induced by the abnormal volume contraction that is ascribed to the formation of double hydrogen bonds at a certain H2O concentration. Therefore, a high-humidity post-treatment strategy is proposed to fabricate alpha-FAPbI(3) solar cells with a champion PCE of 20.19% (0.1 cm(2)) and 18.91% (1 cm(2)), which is currently the highest recorded value in vapor deposited pure alpha-FAPbI(3) perovskite solar cells. This study helps to redefine the effect of a water molecule on FAPbI(3) solar cells. In addition, the demonstrated scaling-up possibility provides another perspective for fabricating uniform high-performance pure alpha-FAPbI(3) perovskite solar cells.
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| 5. |
- Zhan, Zhenye, et al.
(author)
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A Perovskite Photodetector Crossbar Array by Vapor Deposition for Dynamic Imaging
- 2022
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In: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 34:51
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Journal article (peer-reviewed)abstract
- With the development of perovskite photodetectors, integrating photodetectors into array image sensors is the next target to pursue. The major obstacle to integrating perovskite photodiodes for dynamic imaging is the optoelectrical crosstalk among the pixels. Herein, a perovskite photodiode-blocking diode (PIN-BD) crossbar array with pixel-wise rectifying property by the vapor deposition method is presented. The PIN-BD shows a large rectification ratio of 3.3 x 10(2) under illumination, suppressing electrical crosstalk to as small as 8.0% in the imaging array. The fast response time of 72.8 ns allows real-time image acquisition by over 25 frames per second. The imaging sensor exhibits excellent imaging capability with a large linear dynamic range of 112 dB with 4096 gray levels and weak light sensitivity under 1.2 lux.
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| 6. |
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| 7. |
- Zhao, Lichen, et al.
(author)
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Enabling full-scale grain boundary mitigation in polycrystalline perovskite solids
- 2022
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In: Science Advances. - : American Association for the Advancement of Science. - 2375-2548. ; 8:35
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Journal article (peer-reviewed)abstract
- There exists a considerable density of interaggregate grain boundaries (GBs) and intra-aggregate GBs in polycrystalline perovskites. Mitigation of intra- aggregate GBs is equally notable to that of interaggregate GBs as intra-aggregate GBs can also cause detrimental effects on the photovoltaic performances of perovskite solar cells (PSCs). Here, we demonstrate full-scale GB mitigation ranging from nanoscale intra-aggregate to submicron-scale interaggregate GBs, by modulating the crystallization kinetics using a judiciously designed brominated arylamine trimer. The optimized GB-mitigated perovskite films exhibit reduced nonradiative recombination, and their corresponding mesostructured PSCs show substantially enhanced device efficiency and long-term stability under illumination, humidity, or heat stress. The versatility of our strategy is also verified upon applying it to different categories of PSCs. Our discovery not only specifies a rarely addressed perspective concerning fundamental studies of perovskites at nanoscale but also opens a route to obtain high-quality solution-processed polycrystalline perovskites for high-performance optoelectronic devices.
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