Self-trapped exciton engineering for white-light emission in colloidal lead-free double perovskite nanocrystals

Cong, Muyu; Yang, Bin; Hong, Feng; Zheng, Tianlong; Sang, Youbao; Guo, Jingwei; Yang, Songqiu; Han, Keli

doi:10.1016/j.scib.2020.03.010

Cited by 87 publications

(92 citation statements)

References 39 publications

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“…All‐inorganic CsPbX 3 ‐type(X=Cl, Br, I) perovskite nanocrystals (NCs) have recently attracted widespread research attention due to their excellent optical properties [8–11] . However, the issues of Pb toxicity and poor stability have severely hindered their practical applications [12–19] . Herein, we report the colloidal synthesis of a new type of all‐inorganic lead‐free perovskite Cs 2 ZrCl 6 NCs.…”

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confidence: 99%

“…[8][9][10][11] However, the issues of Pb toxicity and poor stability have severely hindered their practical applications. [12][13][14][15][16][17][18][19] Herein, we report the colloidal synthesis of a new type of all-inorganic lead-free perovskite Cs 2 ZrCl 6 NCs. Their unique vacancy-ordered structure results in strongly localized charge-carriers with the formation of self-trapped excitons (STEs).…”

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Efficient Thermally Activated Delayed Fluorescence from All‐Inorganic Cesium Zirconium Halide Perovskite Nanocrystals

et al. 2020

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Thermally activated delayed fluorescence (TADF) is generally observed in solid-state organic molecules or metalorganic complexes. However, TADF in all-inorganic colloidal nanocrystals (NCs) is rare. Herein, we report the first colloidal synthesis of an air-stable all-inorganic lead-free Cs 2 ZrCl 6 perovskite NCs. The Cs 2 ZrCl 6 NCs exhibit long-lived triplet excited state (138.2 ms), and feature high photoluminescence (PL) quantum efficiency (QY = 60.37 %) due to TADF mechanism. The emission color can be easily tuned from blue to green by synthesizing the mixed-halide Cs 2 ZrBr x Cl 6Àx (0 x 1.5) NCs. Femtosecond transient absorption and temperature dependent PL measurements are performed to clarify the emission mechanism. In addition, Bi 3+ ions are successfully doped into Cs 2 ZrCl 6 NCs, which further extends the PL properties. This work not only develops a new lead-free halide perovskite NCs for potential optoelectronic applications, but also offers unique strategies for developing new inorganic phosphors.

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Efficient Thermally Activated Delayed Fluorescence from All‐Inorganic Cesium Zirconium Halide Perovskite Nanocrystals

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“…So far, several works have reported on leadfree perovskites; among these are Bi, Sn, and Ge-based perovskites. [10][11][12][13][14][15][16][17] However, oxidation of Sn 2+ and Ge 2+ in ambient conditions limits their synthesis and application in natural environments. Bismuth-based perovskites do not suffer from this effect and are strong candidates for non-toxic and stable perovskite material.…”

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Room temperature synthesis and characterization of novel lead-free double perovskite nanocrystals with a stable and broadband emission

et al. 2021

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“…It is noted that due to the strong carrier-phonon coupling, the formation time of STEs in lead-free perovskites is typically faster than that in lead perovskite. [16,38,39] The dynamic features of PIA for the two NCs reflect the depopulation of the excited STEs. We then compared the PIA dynamics for Cs 4 The dynamic PL-brightening factor ϕ = τ 80K /τ 300K (τ 80K and τ 300K are the average PL lifetimes at 80 and 300 K, respectively).…”

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Efficient Luminescent Halide Quadruple‐Perovskite Nanocrystals via Trap‐Engineering for Highly Sensitive Photodetectors

et al. 2021

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elements to replace lead due to the high toxicity. Lead-free halide perovskite NCs have recently received increasing attention for their low toxicity, high stability, and chemical diversity. [3-8] The most direct way is usually isovalent substitution of Pb 2+ with Sn 2+. [3] Unfortunately, lead-free CsSnX 3 (X = Cl, Br, and I) NCs is extremely unstable because of the easy oxidation of Sn 2+ into Sn 4+ in air. [3] Subsequently, A 3 M ' 2 X 9-type layer perovskite, A 2 MM ' X 6-type, and A 2 BX 6-type double perovskite (where A denotes alkali-metal ions; M, M' and B denotes monovalent-, trivalent-, and tetravalent-cations; X denotes halogen ions) with high stability have been reported. [9-20] However, optoelectronic devices based on these lead-free perovskite NCs have made limited progress. Such as, photodetectors based on lead-free perovskite NCs exhibited low responsivity (typically <1 A W −1). [17,18] This is mainly due to the low crystallinity, prominent charge-carrier trapping, and short charge-carrier lifetimes of these NCs. In this paper, we report, for the first time, the colloidal synthesis of a series of trigonal (R3̅ m) vacancy-ordered quadrupleperovskite NCs, i.e., Cs 4 CdSb 2 Cl 12 , Cs 4 MnSb 2 Cl 12 , Cs 4 CdBi 2 Cl 12 , and Cs 4 MnBi 2 Cl 12. The photoluminescence quantum yield (PLQY) can be enhanced by 96-fold while the PL lifetime can be enhanced by 77-fold in Cs 4 MnBi 2 Cl 12 NCs through metal alloying. Studies of the charge-carrier dynamics including temperature-dependent PL and femtosecond (fs) transient absorption (TA) measurements were performed to clarify the mechanism of the PL enhancement, which is due to the elimination of the charge-carrier trapping process and increased crystallinity. Besides, the PL-peak position can be tuned continuously from 590 to 640 nm by changing the MnCl bond distance via metal alloying. Finally, we fabricate photodetectors based on quadruple-perovskite NCs, which exhibit high responsivity (0.98 × 10 4 A W −1) and an EQE of 3 × 10 6 %. The responsivity is much higher than previous reported photodetectors base on lead-free perovskite NCs. These results show that quadruple-perovskite NCs open new possibilities for optoelectronic applications. The colloidal synthesis of halide quadruple-perovskite NCs was performed using a modified hot-injection method-for details see the Experimental Section. [14] As shown in Figure 1a,b, replacing M in A 2 MM'X 6 with one M'' (M'' denotes a +2 cation) The colloidal synthesis of a new type of lead-free halide quadruple-perovskite nanocrystals (NCs) is reported. The photoluminescence quantum yield and charge-carrier lifetime of quadruple-perovskite NCs can be enhanced by 96 and 77-fold, respectively, via metal alloying. Study of charge-carrier dynamics provide solid demonstrate that the PL enhancement is due to the elimination of ultrafast (1.4 ps) charge-carrier trapping processes in the alloyed NCs. Thanks to the high crystallinity, low trap-state density, and long carrier lifetime (193.4 μs), the alloyed quadruple-perovskite N...

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Self-trapped exciton engineering for white-light emission in colloidal lead-free double perovskite nanocrystals

Cited by 87 publications

References 39 publications

Efficient Thermally Activated Delayed Fluorescence from All‐Inorganic Cesium Zirconium Halide Perovskite Nanocrystals

Efficient Thermally Activated Delayed Fluorescence from All‐Inorganic Cesium Zirconium Halide Perovskite Nanocrystals

Room temperature synthesis and characterization of novel lead-free double perovskite nanocrystals with a stable and broadband emission

Efficient Luminescent Halide Quadruple‐Perovskite Nanocrystals via Trap‐Engineering for Highly Sensitive Photodetectors

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