Stabilization of Lead-Reduced Metal Halide Perovskite Nanocrystals by High-Entropy Alloying

Solari, Simon F.; Poon, Lok-Nga; Wörle, Michael; Krumeich, Frank; Li, Yen‐Ting; Chiu, Yu‐Cheng; Shih, Chih‐Jen

doi:10.1021/jacs.1c12294

Cited by 36 publications

(35 citation statements)

References 66 publications

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“…The strategy significantly reduces the Pb content while still resulting in samples that exhibit excellent optical properties and colloidal stability. 62 This implies that the alloy entropic effect we pointed out can be…”

Section: T H Imentioning

confidence: 99%

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Entropy-Driven Stabilization of Multielement Halide Double-Perovskite Alloys

Wang

Yang

Wang

et al. 2022

J. Phys. Chem. Lett.

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Currently, a major obstacle restricting the commercial application of halide perovskites is their low thermodynamic stability. Herein, inspired by the high-stability high-entropy alloys, we theoretically investigated a variety of multielement double-perovskite alloys. First-principles calculations show that the entropy contribution to Gibbs free energy, which offsets the positive enthalpy contribution by up to 35 meV/f.u., can significantly enhance the material stability of double-perovskite alloys. We found that the electronic properties of bandgaps (1.04–2.21 eV) and carrier effective masses (0.34 to greater than 2 m 0) of the multielement double-perovskite alloys can be tuned over a wide range. Meanwhile, the parity-forbidden condition of optical transitions in the Cs2AgInCl6 perovskite can be broken because of the lower symmetry of the configurational disorder, leading to enhanced transition intensity. This work demonstrates a promising strategy by utilizing the alloy entropic effect to further improve the material stability and optoelectronic performance of halide perovskites.

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Section: T H Imentioning

confidence: 99%

“…in MAPbBr 3 were prepared. The strategy significantly reduces the Pb content while still resulting in samples that exhibit excellent optical properties and colloidal stability . This implies that the alloy entropic effect we pointed out can be further exploited to improve material stability and optoelectronic performance of halide perovskites.…”

mentioning

confidence: 99%

Entropy-Driven Stabilization of Multielement Halide Double-Perovskite Alloys

Wang

Yang

Wang

et al. 2022

J. Phys. Chem. Lett.

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“…We speculated that the flash film forming process during thermal quenching froze volatile ions and enabled the system to enter a non‐equilibrium state. The kinetic control of the thermodynamic mixing [ 39 ] makes it possible to form uneven distribution of Cl − in doped crystalline solid solution with entropy gain [ 40,41 ] and higher energy barrier, [ 42 ] which maintained the reinforced surface with compressed and denser lattice structure, just as that was observed in TEM images (detailed discussions were shown in Discussion S2 in the Supporting Information). Furthermore, this can also explain why the chlorine content was also gradually increasing in the region near the bottom interface which was close to the cooler substrate and cooled more quickly.…”

Section: Resultsmentioning

confidence: 99%

Thermal Shock Fabrication of Ion‐Stabilized Perovskite and Solar Cells

Kang

Wang

et al. 2022

Advanced Materials

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high efficiency and stable operation of PSCs simultaneously when the bias and high temperature are involved in longterm real working condition. The low ionic migration activation energy (E a ) resulting in a low ionic activated temperature near room temperature (RT) is believed to be the origin of ion migration effect of OIHP devices under working bias. [16] Huang and co-workers [17] reported that in bulk single-crystalline CH 3 NH 3 PbI 3 (MPI), the E a was 0.624 eV under the electric field of 0.4 V µm −1 in dark and the ionic activated temperature was 276 K, while the E a further decreased to 0.338 eV under illumination. Meanwhile, the E a would further deteriorate in polycrystalline perovskite thin films to almost half of that in single crystals due to the much lower E a in amorphous or low-crystallized grain boundaries (GBs). These regions were proved as major ion migration pathways rather than in bulk. [12,18] Most critically, there is always much higher working temperature and stronger illumination in real working condition of OIHP devices, which would further boost the ion migration effect and thus accelerate the decomposition of perovskites. [19,20] Great efforts have been made from both materials and devices to mitigate the bias-induced ionic instability of perovskites. On one hand, improving the crystallinity of perovskite thin films toward single crystal is one efficient strategy to reduce ion migration pathways by suppressing the ratio of GBs [21] and high operational stability is reported in coplanar structured MAPbI 3 single crystal devices. [22] On the other hand, most efficient OIHP devices are based on polycrystalline thin film structures, thus composition engineering to enhance intrinsic stability of OIHP materials, such as introducing low-dimensional [23] or inorganic structures, [24] and interfaces engineering for defects passivation of GBs [25][26][27] are the main strategies to optimize the stability of PSCs. However, the carrier transport and ionic properties are still limited by the intrinsic bulk grain with soft lattice. [26] So it is imperative to ameliorate the intrinsic ionic stability of OIHPs under operation condition without compromising device efficiency and solution-processable advantages.Recently, it is found that strain engineering showed potential to provide another pathway to stabilize perovskite materials as well as devices by inhibiting ion migration. [28][29][30] However, it is still controversial whether the mechanical interaction between the thin interface layer and the nonepitaxial perovskite layer offsetting the residual strain. Meanwhile, the annealing-related modification process will generate additional disturbance about A highly crystalline tempered-glass-like perovskite grain structure with compressed surface lattice realized by a thermal-shocking fabrication is shown. The strained perovskite grain structure is stabilized by Cl − -reinforcing surface lattice and shows enhanced bonding energy and ionic activation temperature, which contributes to hysteresis-free ope...

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“…This may be attributed to the doped Cu 2+ ions inducing defects elimination, which increases the lattice formation energy and enhances the short-range ordering degree of doped perovskite NCs, as discussed in the previous study. 12 Therefore, Cu 2+ doping represents an effective way to improve the thermal stability of CsPb 2 Br 5 /CsPbBr 3 NCs.…”

Section: Resultsmentioning

confidence: 99%

“…10 Recently, all-inorganic perovskites (Cs-Pb-X, X = Cl, Br, and I) without organic cations have attracted great attention and have been proposed as one of the most promising perovskite candidates for optoelectronics, owing to their remarkable chemical stability and unique electronic properties as compared to their hybrid organic-inorganic counterparts. 11,12 Therefore, great efforts have been devoted to the synthesis of inorganic perovskite colloidal NCs with high luminescence and stability. 13 For example, Kovalenko et al first synthesized all-inorganic CsPbX 3 perovskite NCs in an organic high-boiling-point solvent (1-octadecene) using a hot-injection approach.…”

Section: Introductionmentioning

confidence: 99%