Highly Emissive Self‐Trapped Excitons in Fully Inorganic Zero‐Dimensional Tin Halides

Benin, Bogdan M.; Dirin, Dmitry N.; Morad, Viktoriia; Wörle, Michael; Yakunin, Sergii; Rainò, Gabriele; Nazarenko, Olga; Fischer, Markus; Infante, Ivan; Kovalenko, Maksym V.

doi:10.1002/anie.201806452

Cited by 281 publications

(318 citation statements)

References 70 publications

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“…In the reflection spectrum, a strong absorption is located at about 328 nm, and the optical bandgap is calculated to be about 3.78 eV. [21][22][23] Similarly, we attribute the broadband luminescence of CsCu 2 I 3 to self-trapped excitons recombination, in whose mechanism the distortion of lattice is the main cause of Stokes shift. And in the excitation spectrum, the crystal has the highest excitation efficiency at about 347 nm, which is consistent with the reflection spectrum.…”

Section: Doi: 101002/adma201905079mentioning

confidence: 78%

“…At about 425 nm, the crystal also has a significant absorption, which can be explained by exciton absorption. [2,21] In other words, large Stokes shift means strong lattice distortion. Figure 2b is the photoluminescence (PL) spectrum at 80 K. The PL spectrum has a wide full-width at half-maximum (FWHM, ≈75 nm) and the luminescence peak is located at 568 nm.…”

Section: Doi: 101002/adma201905079mentioning

confidence: 99%

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All‐Inorganic CsCu₂I₃ Single Crystal with High‐PLQY (≈15.7%) Intrinsic White‐Light Emission via Strongly Localized 1D Excitonic Recombination

et al. 2019

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In order to achieve a high quantum efficiency, doping crystals with appropriate elements such as sodium cations (ref. [8]) to reduce electronic dimension is a useful method. [5,8] However, doping also tends to cause nonradiation recombination loss. [13] Therefore, a reliable and promising way is to synthesize high-quality inorganic metal halide single crystal (SC) with natural lowdimensional structure to realize stable and high quantum efficiency white-light illumination application.In this work, we successfully synthesized 1D CsCu 2 I 3 SC by replacing toxic Pb with eco-friendly and abundant Cu, and organic molecules with large-radius Cs. [12,13] The "one dimension" we noted here is localized dimension of electron. [14] Through density functional theory (DFT) calculation, in 1D CsCu 2 I 3 SC, [Cu 2 I 3 ] − octahedra contributes most electronic states, and Cs + only forms a 1D electronic structure with isolated [Cu 2 I 3 ] − in 2D direction. Therefore, CsCu 2 I 3 SC obtains a high photoluminescence quantum yield (PLQY ≈15.7%) of the IWE at room temperature. [2] We also calculated that the crystal has a high radiation recombination rate which is owning to the 1D localized electronic structure, and this rate is the key to its high PLQY. [15,16] Under a strong injection and atmospheric environment, the PL intensity of all-inorganic CsCu 2 I 3 SC only decays about 5% after 750 min ( Figure S5, Supporting Information). This excellent stability demonstrates that the all-inorganic CsCu 2 I 3 SC possesses a great prospect in high-efficiency lighting applications.High-quality CsCu 2 I 3 SCs were synthesized by antisolvent infiltration method. [17,18] Cesium iodide and cuprous (I) iodide in certain ratio were dissolved in dimethyl formamide (DMF)dimethyl sulfoxide (DMSO) (4:1) to obtain a saturated solution. Then, methanol (antisolvent) was slowly dropped into the saturated solution to form a white precipitate (the white precipitate quickly dissolved again) until it no longer dissolved. The solution was filtered and then placed in a beaker with methanol atmosphere to grow crystals. Several days later, centimeter-scale high-quality CsCu 2 I 3 SCs were obtained (refer to the Supporting information and the Experimental Section for more details). Figure 1a shows an optical image of a rod-shaped CsCu 2 I 3 SCs excited by ultraviolet light. The SC has a size of about 10 mm × 1.5 mm, being colorless and transparent at room temperature but having strong white-light emission under ultraviolet light. Crystal structure of the CsCu 2 I 3 SC was obtained through single-crystal X-ray diffraction (SCXRD) test (Figure 1b,c), which belongs to orthorhombic system. The 1D Energy-saving white lighting from the efficient intrinsic emission of semiconductors is considered as a next-generation lighting source. Currently, white-light emission can be composited with a blue light-emitting diode and yellow phosphor. However, this solution has an inevitable light loss, which makes the improvement of the energy utilization efficiency more difficult. T...

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Section: Doi: 101002/adma201905079mentioning

confidence: 78%

Section: Doi: 101002/adma201905079mentioning

confidence: 99%

All‐Inorganic CsCu₂I₃ Single Crystal with High‐PLQY (≈15.7%) Intrinsic White‐Light Emission via Strongly Localized 1D Excitonic Recombination

et al. 2019

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“…[19] In view of the above discussion, ap robable reason for the broad emission and large Stokes shift of the 0D Cs 3 Cu 2 I 5 NCs is the STEs,asobserved in other 0D metal halide systems. [17,20] Evidence for STEs can be obtained using femtosecond transient absorption (TA) spectroscopy.F igure 4a presents the pseudocolor TA plot of the Cs 3 Cu 2 I 5 NCs as afunction of the wavelength and decay time.L aser excitation at l = 285 nm resulted in the TA spectra of Cs 3 Cu 2 I 5 NCs exhibiting ab road excited-state absorption plateau across the probe region (l = 400-700 nm), which is direct evidence for the formation of STEs. [21] Ther ise time of the photoinduced absorption (PIA) band probed at different wavelengths (l = 450, 550, and 650 nm) is within the resolution of the instrumental response (ca.…”

Section: Communicationsmentioning

confidence: 99%

Colloidal Synthesis and Optical Properties of All‐Inorganic Low‐Dimensional Cesium Copper Halide Nanocrystals

et al. 2019

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Low-dimensional metal halides have recently attracted extensive attention owing to their unique structure and photoelectric properties.H erein, we report the colloidal synthesis of all-inorganic low-dimensional cesium copper halide nanocrystals (NCs) by adopting ah ot-injection approach.U sing the same reactants and ligands,b ut different reaction temperatures,b oth 1D CsCu 2 I 3 nanorods and 0D Cs 3 Cu 2 I 5 NCs can be prepared. Density functional theory indicates that the reduced dimensionality in 1D CsCu 2 I 3 compared to 0D Cs 3 Cu 2 I 5 makes the excitons more localized, which accounts for the strong emission of 0D Cs 3 Cu 2 I 5 NCs. Subsequent optical characterization reveals that the highly luminescent, strongly Stokes-shifted broadband emission of 0D Cs 3 Cu 2 I 5 NCs arises from the self-trapped excitons.O ur findings not only present am ethod to control the synthesis of low-dimensional cesium copper halide nanocrystals but also highlight the potential of 0D Cs 3 Cu 2 I 5 NCs in optoelectronics. Scheme 1. Colloidal synthesis of cesium copper halide nanocrystals.Supportinginformation and the ORCID identification number for one of the authors of this article can be found under: https://doi.

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“…For Cs4SnBr6 at RT, the tails of the two bands touch each other despite a large measured Stokes shift of 1.35 eV. [30] The measured Stokes shift in Cs4PbBr6 is only 0.69 eV, [28] which is too small to prevent the spectral overlap as temperature rises. This explains the highly emissive STE in Cs4SnBr6 [30] as opposed to the absence of STE emission in Cs4PbBr6 at RT.…”

Section: Resultsmentioning

confidence: 99%

“…This should be due to the strong exciton localization at Eu 2+ ions. More recently, Benin et al studied luminescent properties in Cs4SnX6 (X = Br, I), [30] which are isostructural to Cs4PbBr6. Although there is also thermal quenching in Cs4SnBr6, it is still highly emissive at RT with PLQE of 15 ± 5%.…”

Section: Introductionmentioning

confidence: 99%

Impact of metal ns2 lone pair on luminescence quantum efficiency in low-dimensional halide perovskites

Shi

Han

Chen

et al. 2019

Phys. Rev. Materials

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Based on first-principles calculations, we show that chemically active metal ns 2 lone pairs play an important role in exciton relaxation and dissociation in low-dimensional halide perovskites. We studied excited-state properties of several recently discovered luminescent all-inorganic and hybrid organic-inorganic zero-dimensional (0D) Sn and Pb halides. The results show that, despite the similarity in ground-state electronic structure between Sn and Pb halide perovskites, the chemically more active Sn 2+ lone pair leads to stronger excited-state structural distortion and larger Stokes shift in Sn halides. The enhanced Stokes shift hinders excitation energy transport, which reduces energy loss to defects and increases the photoluminescence quantum efficiency (PLQE).The presence of the ns 2 metal cations in the 0D halide perovskites also promotes the exciton dissociation into electron and hole polarons especially in all-inorganic compounds, in which the coupling between metal-halide clusters is significant.

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Highly Emissive Self‐Trapped Excitons in Fully Inorganic Zero‐Dimensional Tin Halides

Cited by 281 publications

References 70 publications

All‐Inorganic CsCu₂I₃ Single Crystal with High‐PLQY (≈15.7%) Intrinsic White‐Light Emission via Strongly Localized 1D Excitonic Recombination

All‐Inorganic CsCu₂I₃ Single Crystal with High‐PLQY (≈15.7%) Intrinsic White‐Light Emission via Strongly Localized 1D Excitonic Recombination

Colloidal Synthesis and Optical Properties of All‐Inorganic Low‐Dimensional Cesium Copper Halide Nanocrystals

Impact of metal ns2 lone pair on luminescence quantum efficiency in low-dimensional halide perovskites

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Highly Emissive Self‐Trapped Excitons in Fully Inorganic Zero‐Dimensional Tin Halides

Cited by 281 publications

References 70 publications

All‐Inorganic CsCu2I3 Single Crystal with High‐PLQY (≈15.7%) Intrinsic White‐Light Emission via Strongly Localized 1D Excitonic Recombination

All‐Inorganic CsCu2I3 Single Crystal with High‐PLQY (≈15.7%) Intrinsic White‐Light Emission via Strongly Localized 1D Excitonic Recombination

Colloidal Synthesis and Optical Properties of All‐Inorganic Low‐Dimensional Cesium Copper Halide Nanocrystals

Impact of metal ns2 lone pair on luminescence quantum efficiency in low-dimensional halide perovskites

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Product

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All‐Inorganic CsCu₂I₃ Single Crystal with High‐PLQY (≈15.7%) Intrinsic White‐Light Emission via Strongly Localized 1D Excitonic Recombination

All‐Inorganic CsCu₂I₃ Single Crystal with High‐PLQY (≈15.7%) Intrinsic White‐Light Emission via Strongly Localized 1D Excitonic Recombination