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Lang Zhou

Bio: Lang Zhou is an academic researcher from Nanchang University. The author has contributed to research in topics: Materials science & Silicon. The author has an hindex of 7, co-authored 9 publications receiving 382 citations.

Papers
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Journal ArticleDOI
Kai Yao1, Xiaofeng Wang1, Yun-Xiang Xu2, Fan Li1, Lang Zhou1 
TL;DR: In this paper, a series of 2D perovskite compounds (PEI)2(MA)n−1PbnI3n+1 (n = 3, 5, 7) were constructed by incorporating polyethylenimine cations within the layered structure.
Abstract: Despite the dramatic rise in power conversion efficiencies (PCEs) of perovskite solar cells (PeSCs), concerns surrounding the long-term stability as well as the poor reproducibility in the archetypal three-dimensional (3D) perovskite, MAPbI3 (MA = CH3NH3), have the potential to derail commercialization. We have reported the fabrication and properties of a series of 2D perovskite compounds (PEI)2(MA)n−1PbnI3n+1 (n = 3, 5, 7) by incorporating polyethylenimine (PEI) cations within the layered structure. The benefits of using intercalated polymer cations in the multilayered films are multiple: moisture resistance and film quality are greatly enhanced compared to that of their 3D MAPbI3 analogue; charge transport within solar cells can also be improved compared to that of 2D materials using small-molecule bulky ammonium. The moisture-stable nature of the multilayered perovskite materials allow for the simple one-step fabrication of cells with an aperture area of 2.32 cm2 under ambient humidity that have a PCE ...

169 citations

Journal ArticleDOI
TL;DR: The compositional engineering of mixed perovskite based on methyl- and polymeric-ammonium exhibits a maximum power conversion efficiency of over 15% with high reproducibility and good stability, offering greater tunability at the molecular level for material optimization.

88 citations

Journal ArticleDOI
28 May 2019-ACS Nano
TL;DR: This core-bishell design concept of plasmonic nanostructures demonstrates a general approach to improving the photovoltaic performance with both optical and electrical contributions.
Abstract: To maximize light coupling into the active layer, plasmonic nanostructures have been incorporated into both active layers of organic solar cells (OSCs) and perovskite solar cells (PSCs) with the aim of increasing light absorption, but reports have shown controversial results in electrical characteristics. In this work, we introduce a core-bishell concept to build plasmonic nanoparticles (NPs) with metal-inorganic semiconductor-organic semiconductor nanostructure. Specifically, Ag NPs were decorated with a titania/benzoic-acid-fullerene bishell (Ag@TiO2@Pa), which enables the NPs to be compatible with fullerene acceptors or a perovskite absorber. Moreover, coating the Ag@TiO2 NP with a fullerene shell can activate efficient plasmon-exciton coupling and eliminate the charge accumulation, thus facilitating exciton dissociation and reducing the monomolecular recombination. The improved light absorption and enhanced carrier extraction of devices with Ag@TiO2@Pa nanoparticles are responsible for the improved short-circuit current and fill factor, respectively. On the basis of the synergistic effects (optical and electrical), a series of plasmonic OSCs exhibited enhancement of 12.3-20.7% with a maximum power conversion efficiency of 13.0%, while the performance of plasmonic PSCs also showed an enhancement by 10.2% from 18.4% to 20.2%. This core-bishell design concept of plasmonic nanostructures demonstrates a general approach to improving the photovoltaic performance with both optical and electrical contributions.

83 citations

Journal ArticleDOI
TL;DR: Li et al. as discussed by the authors developed high-performance perovskite X-ray detectors with excellent stability by synergistic composition engineering, where they include A-site alloys to decrease the trap density and B-site dopants to release the microstrain induced by a-site alloying.
Abstract: Abstract Although three-dimensional metal halide perovskite (ABX 3 ) single crystals are promising next-generation materials for radiation detection, state-of-the-art perovskite X-ray detectors include methylammonium as A-site cations, limiting the operational stability. Previous efforts to improve the stability using formamidinium–caesium-alloyed A-site cations usually sacrifice the detection performance because of high trap densities. Here we successfully solve this trade-off between stability and detection performance by synergistic composition engineering, where we include A-site alloys to decrease the trap density and B-site dopants to release the microstrain induced by A-site alloying. As such, we develop high-performance perovskite X-ray detectors with excellent stability. Our X-ray detectors exhibit high sensitivity of (2.6 ± 0.1) × 10 4 μC Gy air −1 cm −2 under 1 V cm −1 and ultralow limit of detection of 7.09 nGy air s −1 . In addition, they feature long-term operational stability over half a year and impressive thermal stability up to 125 °C. We further demonstrate the promise of our perovskite X-ray detectors for low-bias portable applications with high-quality X-ray imaging and monitoring prototypes.

62 citations

Journal ArticleDOI
20 Feb 2019-Joule
TL;DR: In this paper, a surface-passivation strategy was adopted by anchoring ZnO nanoparticles with fullerene nano-shells (Fa-ZnO) to mitigate trap states and passivate surface hydroxyl groups.

58 citations


Cited by
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Journal ArticleDOI
TL;DR: This review will explore beyond the current focus on three-dimensional (3-D) lead(II) halide perovskites, to highlight the great chemical flexibility and outstanding potential of the broader class of 3-D and lower dimensional organic-based perovSKite family for electronic, optical, and energy-based applications as well as fundamental research.
Abstract: Although known since the late 19th century, organic–inorganic perovskites have recently received extraordinary research community attention because of their unique physical properties, which make them promising candidates for application in photovoltaic (PV) and related optoelectronic devices. This review will explore beyond the current focus on three-dimensional (3-D) lead(II) halide perovskites, to highlight the great chemical flexibility and outstanding potential of the broader class of 3-D and lower dimensional organic-based perovskite family for electronic, optical, and energy-based applications as well as fundamental research. The concept of a multifunctional organic–inorganic hybrid, in which the organic and inorganic structural components provide intentional, unique, and hopefully synergistic features to the compound, represents an important contemporary target.

1,962 citations

Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper introduced n-butylammonium cations into a mixed-cation lead mixed-halide FA0.83Cs0.17Pb(IyBr1−y)3 3D perovskite.
Abstract: Perovskite solar cells are remarkably efficient; however, they are prone to degradation in water, oxygen and ultraviolet light. Cation engineering in 3D perovskite absorbers has led to reduced degradation. Alternatively, 2D Ruddlesden–Popper layered perovskites exhibit improved stability, but have not delivered efficient solar cells so far. Here, we introduce n-butylammonium cations into a mixed-cation lead mixed-halide FA0.83Cs0.17Pb(IyBr1−y)3 3D perovskite. We observe the formation of 2D perovskite platelets, interspersed between highly orientated 3D perovskite grains, which suppress non-radiative charge recombination. We investigate the relationship between thin-film composition, crystal alignment and device performance. Solar cells with an optimal butylammonium content exhibit average stabilized power conversion efficiency of 17.5 ± 1.3% with a 1.61-eV-bandgap perovskite and 15.8 ± 0.8% with a 1.72-eV-bandgap perovskite. The stability under simulated sunlight is also enhanced. Cells sustain 80% of their ‘post burn-in’ efficiency after 1,000 h in air, and close to 4,000 h when encapsulated. Various strategies are developed to combine high efficiency and stability in perovskite solar cells. Here, Wang et al. mix 2D and 3D mixed-cation and mixed-halide perovskite phases in solar cells with stabilized efficiencies up to 19.5% and improved stability under full illumination and ambient air.

1,079 citations

Journal ArticleDOI
TL;DR: In this article, a review of the state of the art in 2D perovskites is provided, providing an overview of structural and materials engineering aspects and optical and photophysical properties.
Abstract: Hybrid perovskites are currently one of the most active fields of research owing to their enormous potential for photovoltaics. The performance of 3D hybrid organic–inorganic perovskite solar cells has increased at an incredible rate, reaching power conversion efficiencies comparable to those of many established technologies. However, the commercial application of 3D hybrid perovskites is inhibited by their poor stability. Relative to 3D hybrid perovskites, low-dimensional — that is, 2D — hybrid perovskites have demonstrated higher moisture stability, offering new approaches to stabilizing perovskite-based photovoltaic devices. Furthermore, 2D hybrid perovskites have versatile structures, enabling the fine-tuning of their optoelectronic properties through compositional engineering. In this Review, we discuss the state of the art in 2D perovskites, providing an overview of structural and materials engineering aspects and optical and photophysical properties. Moreover, we discuss recent developments along with the main limitations of 3D perovskites and assess the advantages of 2D perovskites over their 3D parent structures in terms of stability. Finally, we review recent achievements in combining 3D and 2D perovskites as an approach to simultaneously boost device efficiency and stability, paving the way for mixed-dimensional perovskite solar cells for commercial applications. Combining low-dimensional and 3D perovskites is a promising approach to achieve stable and efficient solar cells. In this Review, we discuss the structural, optical and photophysical properties of low-dimensional perovskites, compare the stability and efficiency of 2D and 3D perovskite devices, and consider 2D/3D composites as a strategy to increase the stability of perovskite solar cells.

572 citations

Journal ArticleDOI
TL;DR: In this paper, the authors summarize the recent progress of ternary solar cells and try to concise out the scientific issues in preparing high performance TSSs, which is the best candidate due to the cell with a high power conversion efficiency, easy fabrication and low cost.
Abstract: The power conversion efficiency (PCE) of organic solar cells has been constantly refreshed in the past ten years from 4% up to 11% due to the contribution from the chemists on novel materials and the physicists on device engineering. For practical applications, a single bulk heterojunction structure may be the best candidate due to the cell with a high PCE, easy fabrication and low cost. Recently, ternary solar cells have attracted much attention due to enhanced photon harvesting by using absorption spectral or energy level complementary materials as the second donor or acceptor based on a single bulk heterojunction structure. For better promoting the development of ternary solar cells, we summarize the recent progress of ternary solar cells and try our best to concise out the scientific issues in preparing high performance ternary solar cells.

562 citations

Journal ArticleDOI
TL;DR: In this paper, a 2D-3D perovskite stacking-layered architecture was designed by in situ growing 2D PEA(2)PbI(4) capping layers on top of 3D PbI film, which drastically improved the stability of PSCs without compromising their high performance.
Abstract: 2D halide perovskites have recently been recognized as a promising avenue in perovskite solar cells (PSCs) in terms of encouraging stability and defect passivation effect. However, the efficiency (less than 15%) of ultrastable 2D Ruddlesden-Popper PSCs still lag far behind their traditional 3D perovskite counterparts. Here, a rationally designed 2D-3D perovskite stacking-layered architecture by in situ growing 2D PEA(2)PbI(4) capping layers on top of 3D perovskite film, which drastically improves the stability of PSCs without compromising their high performance, is reported. Such a 2D perovskite capping layer induces larger Fermi-level splitting in the 2D-3D perovskite film under light illumination, resulting in an enhanced open-circuit voltage (V-oc) and thus a higher efficiency of 18.51% in the 2D-3D PSCs. Time-resolved photoluminescence decay measurements indicate the facilitated hole extraction in the 2D-3D stacking-layered perovskite films, which is ascribed to the optimized energy band alignment and reduced nonradiative recombination at the subgap states. Benefiting from the high moisture resistivity as well as suppressed ion migration of the 2D perovskite, the 2D-3D PSCs show significantly improved long-term stability, retaining nearly 90% of the initial power conversion efficiency after 1000 h exposure in the ambient conditions with a high relative humidity level of 60 +/- 10%.

523 citations