| 1. |
- Bao, Chunxiong, et al.
(författare)
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Bidirectional optical signal transmission between two identical devices using perovskite diodes
- 2020
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Ingår i: NATURE ELECTRONICS. - : NATURE PUBLISHING GROUP. - 2520-1131. ; 3:3, s. 156-164
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Tidskriftsartikel (refereegranskat)abstract
- A solution-processed perovskite diode that functions as both optical transmitter and receiver can be used to build a monolithic pulse sensor and a bidirectional optical communication system. The integration of optical signal generation and reception into one device-thus allowing a bidirectional optical signal transmission between two identical devices-is of value in the development of miniaturized and integrated optoelectronic devices. However, conventional solution-processable semiconductors have intrinsic material and design limitations that prevent them from being used to create such devices with a high performance. Here we report an efficient solution-processed perovskite diode that is capable of working in both emission and detection modes. The device can be switched between modes by changing the bias direction, and it exhibits light emission with an external quantum efficiency of over 21% and a light detection limit on a subpicowatt scale. The operation speed for both functions can reach tens of megahertz. Benefiting from the small Stokes shift of perovskites, our diodes exhibit a high specific detectivity (more than 2 x 10(12) Jones) at its peak emission (~804 nm), which allows an optical signal exchange between two identical diodes. To illustrate the potential of the dual-functional diode, we show that it can be used to create a monolithic pulse sensor and a bidirectional optical communication system.
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| 2. |
- Cheng, Jie, et al.
(författare)
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Interactions in Composite Film Formation of Mefp-1/graphene on Carbon Steel
- 2021
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Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- Mefp-1 adhesive protein derived from marine blue mussels, together with the 2D material graphene, was used to build the green composite film with enhanced anti-corrosion property and mechanical strength. The corrosion inhibition of the composite film, formed by different methods, was evaluated by using electrochemical impedance spectroscopy. The non-degraded adhesion of the composite film to the carbon steel substrate was proved by nano-scratch tests. Infrared spectroscopy was utilized to investigate the film formation process and "three-body interactions " between Mefp-1, graphene and carbon steel surface. The results show that the Mefp-1 adsorbs on the carbon steel surface mainly through the covalent bond between catechols and Fe(III). Meanwhile, Mefp-1 can bond to non-adhesive graphene by forming hydrogen bonds and pi-pi interaction non-covalent bonds, which facilitate the formation of a robust Mefp-1/graphene composite film on the carbon steel surface.
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| 3. |
- Karlsson, Max, et al.
(författare)
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Mixed halide perovskites for spectrally stable and high-efficiency blue light-emitting diodes
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Bright and efficient blue emission is key to further development of metal halide perovskite light-emitting diodes. Although modifying bromide/chloride composition is straightforward to achieve blue emission, practical implementation of this strategy has been challenging due to poor colour stability and severe photoluminescence quenching. Both detrimental effects become increasingly prominent in perovskites with the high chloride content needed to produce blue emission. Here, we solve these critical challenges in mixed halide perovskites and demonstrate spectrally stable blue perovskite light-emitting diodes over a wide range of emission wavelengths from 490 to 451 nanometres. The emission colour is directly tuned by modifying the halide composition. Particularly, our blue and deep-blue light-emitting diodes based on three-dimensional perovskites show high EQE values of 11.0% and 5.5% with emission peaks at 477 and 467 nm, respectively. These achievements are enabled by a vapour-assisted crystallization technique, which largely mitigates local compositional heterogeneity and ion migration.
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| 4. |
- Zhao, Haifeng, et al.
(författare)
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High-Brightness Perovskite Light-Emitting Diodes Based on FAPbBr(3) Nanocrystals with Rationally Designed Aromatic Ligands
- 2021
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Ingår i: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 6:7, s. 2395-2403
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Tidskriftsartikel (refereegranskat)abstract
- Despite rapid developments of light-emitting diodes (LEDs) based on emerging perovskite nanocrystals (PeNCs), it remains challenging to achieve devices with integrated high efficiencies and high brightness because of the insulating long-chain ligands used for the PeNCs. Herein, we develop highly luminescent and stable formamidinium lead bromide PeNCs capped with rationally designed short aromatic ligands of 2-naphthalenesulfonic acid (NSA) for LEDs. Compared with commonly used oleic acid ligands, the NSA molecules not only preserve the surface properties of the PeNCs during the purification but also notably improve the electrical properties of the assembled emissive layers, ensuring efficient charge injection/transport in the devices. The resulting champion LED with electroluminescence approaching the Rec. 2020 green primary color demonstrates a high brightness of 67 115 cd cm(-2) and a peak external quantum efficiency of 19.2%. More impressively, the device shows negligibly decreased efficiency at an elevated brightness of 20 000 cd cm(-2) and a well-retained efficiency of over 10% at around 65 000 cd cm(-2), presenting a breakthrough in LEDs based on PeNCs.
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| 5. |
- Zou, Yatao, et al.
(författare)
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Manipulating crystallization dynamics through chelating molecules for bright perovskite emitters
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Molecular additives are widely utilized to minimize non-radiative recombination in metal halide perovskite emitters due to their passivation effects from chemical bonds with ionic defects. However, a general and puzzling observation that can hardly be rationalized by passivation alone is that most of the molecular additives enabling high-efficiency perovskite light-emitting diodes (PeLEDs) are chelating (multidentate) molecules, while their respective monodentate counterparts receive limited attention. Here, we reveal the largely ignored yet critical role of the chelate effect on governing crystallization dynamics of perovskite emitters and mitigating trap-mediated non-radiative losses. Specifically, we discover that the chelate effect enhances lead-additive coordination affinity, enabling the formation of thermodynamically stable intermediate phases and inhibiting halide coordination-driven perovskite nucleation. The retarded perovskite nucleation and crystal growth are key to high crystal quality and thus efficient electroluminescence. Our work elucidates the full effects of molecular additives on PeLEDs by uncovering the chelate effect as an important feature within perovskite crystallization. As such, we open new prospects for the rationalized screening of highly effective molecular additives.
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