| 1. |
- Han, Peigeng, et al.
(författare)
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Size effect of lead-free halide double perovskite on luminescence property
- 2019
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Ingår i: Science China Chemistry. - : Springer Science and Business Media LLC. - 1674-7291 .- 1869-1870. ; 62:10, s. 1405-1413
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Tidskriftsartikel (refereegranskat)abstract
- Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable. However, compared to the lead perovskites, their optoelectronic properties are compromised. Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites: Cs2AgBi1−xInxCl6 (0
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| 2. |
- Yang, B, et al.
(författare)
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Lead-Free, Air-Stable All-Inorganic Cesium Bismuth Halide Perovskite Nanocrystals
- 2017
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Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 56:41, s. 12471-12475
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Tidskriftsartikel (refereegranskat)abstract
- Lead-based perovskite nanocrystals (NCs) have outstanding optical properties and cheap synthesis conferring them a tremendous potential in the field of optoelectronic devices. However, two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead-based and the other is the poor stability. Lead-free all-inorganic perovskite Cs3Bi2X9 (X=Cl, Br, I) NCs are synthesized with emission wavelength ranging from 400 to 560nm synthesized by a facile room temperature reaction. The ligand-free Cs3Bi2Br9 NCs exhibit blue emission with photoluminescence quantum efficiency (PLQE) about 0.2%. The PLQE can be increased to 4.5% when extra surfactant (oleic acid) is added during the synthesis processes. This improvement stems from passivation of the fast trapping process (2-20ps). Notably, the trap states can also be passivated under humid conditions, and the NCs exhibited high stability towards air exposure exceeding 30days.
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| 3. |
- Yang, Bin, et al.
(författare)
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Lead-Free Silver-Bismuth Halide Double Perovskite Nanocrystals
- 2018
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Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 57:19, s. 5359-5363
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Tidskriftsartikel (refereegranskat)abstract
- Lead-free perovskite nanocrystals (NCs) were obtained mainly by substituting a Pb2+ cation with a divalent cation or substituting three Pb2+ cations with two trivalent cations. The substitution of two Pb2+ cations with one monovalent Ag+ and one trivalent Bi3+ cations was used to synthesize Cs2AgBiX6 (X=Cl, Br, I) double perovskite NCs. Using femtosecond transient absorption spectroscopy, the charge carrier relaxation mechanism was elucidated in the double perovskite NCs. The Cs2AgBiBr6 NCs exhibit ultrafast hot-carrier cooling (<1 ps), which competes with the carrier trapping processes (mainly originate from the surface defects). Notably, the photoluminescence can be increased by 100 times with surfactant (oleic acid) added to passivate the defects in Cs2AgBiCl6 NCs. These results suggest that the double perovskite NCs could be potential materials for optoelectronic applications by better controlling the surface defects.
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| 4. |
- Yang, B, et al.
(författare)
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Ultrasensitive and Fast All-Inorganic Perovskite-Based Photodetector via Fast Carrier Diffusion
- 2017
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648. ; 29:40, s. 1703758-1703758
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Tidskriftsartikel (refereegranskat)abstract
- Low trap-state density, high carrier mobility, and efficient charge carrier collection are key parameters for photodetectors with high sensitivity and fast response time. This study demonstrates a simple solution growth method to prepare CsPbBr3 microcrystals (MCs) with low trap-state density. Time-dependent photoluminescence study with one-photon excitation (OPE) and two-photon excitation (TPE) indicates that CsPbBr3 MCs exhibit fast carrier diffusion with carrier mobility over 100 cm2 V-1 S-1. Furthermore, CsPbBr3 MC-based photodetectors with high charge carriers' collection efficiency are fabricated. Such photodetectors show ultrahigh responsivity (R) up to 6 × 104 A W-1 with OPE and high R up to 6 A W-1 with TPE. The R for OPE is over one order of magnitude higher (the R for TPE is three orders of magnitude higher) than that of previously reported all-inorganic perovskite-based photodetectors. Moreover, the photodetectors exhibit fast response time of ≈1 ms, which corresponds to a gain ≈105 and a gain- bandwidth product of 108 Hz for OPE (a gain ≈103 and a gain-bandwidth product of 106 Hz for TPE).
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| 5. |
- Zhang, Fengying, et al.
(författare)
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Formamidinium Lead Bromide (FAPbBr3) Perovskite Microcrystals for Sensitive and Fast Photodetectors
- 2018
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Ingår i: Nano-Micro Letters. - : Springer Science and Business Media LLC. - 2311-6706 .- 2150-5551. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Because of the good thermal stability and superior carrier transport characteristics of formamidinium lead trihalide perovskite HC(NH2)2PbX3 (FAPbX3), it has been considered to be a better optoelectronic material than conventional CH3NH3PbX3 (MAPbX3). Herein, we fabricated a FAPbBr3 microcrystal-based photodetector that exhibited a good responsivity of 4000 A W−1 and external quantum efficiency up to 106% under one-photon excitation, corresponding to the detectivity greater than 1014 Jones. The responsivity is two orders of magnitude higher than that of previously reported formamidinium perovskite photodetectors. Furthermore, the FAPbBr3 photodetector’s responsivity to two-photon absorption with an 800-nm excitation source can reach 0.07 A W−1, which is four orders of magnitude higher than that of its MAPbBr3 counterparts. The response time of this photodetector is less than 1 ms. This study provides solid evidence that FAPbBr3 can be an excellent candidate for highly sensitive and fast photodetectors.[Figure not available: see fulltext.].
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