Mixed-Halide Perovskites with Stabilized Bandgaps

Xiao, Zhengguo; Zhao, Lianfeng; Tran, Nhu L.; Lin, Yuehe; Silver, Scott; Kerner, Ross A.; Yao, Nan; Kahn, Antoine; Scholes, Gregory D.; Rand, Barry P.

doi:10.1021/acs.nanolett.7b03179

Cited by 178 publications

(219 citation statements)

References 29 publications

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“…The photo‐induced halide segregation seriously damages the device performance, leads to open‐circuit voltage ( V oc ) decrease and photo‐induced traps. It is demonstrated that the photo‐induced halide segregation is affected by lattice strain, traps, light intensity, pressure, or compositional uniformity, but the origin is still unclear . Since the halide segregation is as the result of ion migration, therefore, it can be suppressed by increasing the ion migration barrier.…”

Section: Materials Stabilitymentioning

confidence: 99%

Inorganic CsPbI₂Br Perovskite Solar Cells: The Progress and Perspective

et al. 2018

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Cesium‐based all‐inorganic perovskite solar cells (PSCs), especially for CsPbI2Br component‐based devices, have attracted increasing attention due to its advantage of superior thermal and phase stability. Since the pioneering study reported in 2016, more than 30 papers have been published, reporting the rapid boost in the power conversion efficiency (PCE) of PSCs to 14.81%. The CsPbI2Br PSC is one of the most remarkable research hotspots in the field of perovskite photovoltaics. In this progress report, the recent advances in CsPbI2Br PSCs are systematically reviewed, which in turn introduces the basic property and stability of active layers, and the performance improvements in these devices. The challenges as well as the possible solutions toward better‐performing CsPbI2Br PSCs are also discussed. The theoretical calculation results point out that there is much room for further device performance enhancement, particularly in open‐circuit voltages. This progress report focuses on CsPbI2Br material properties and summarizes recent strategies to improve the corresponding device's PCE, in order to open new perspectives toward commercial utility of PSCs.

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Section: Materials Stabilitymentioning

confidence: 99%

Inorganic CsPbI₂Br Perovskite Solar Cells: The Progress and Perspective

et al. 2018

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“…Besides their sensitivity to moisture, oxygen, light, electric field, or thermal stress, an existing self-degradation pathway [26,27] is also a big issue in hybrid organic-inorganic lead halide perovskites. [28][29][30][31][32] The group IV elements, tin (Sn) [23,[33][34][35] and germanium (Ge), [34,36] have been employed as the replacements for Pb. [28][29][30][31][32] The group IV elements, tin (Sn) [23,[33][34][35] and germanium (Ge), [34,36] have been employed as the replacements for Pb.…”

mentioning

confidence: 99%

Progress of Lead‐Free Halide Double Perovskites

Igbari

Wang

Liao

2019

Advanced Energy Materials

380

305

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Although impressive performance has been obtained, PSCs are still far from commercial or real-life availability due to serious issues such as toxicity [15,16] and poor stability to heat, [17] oxygen, [18] moisture, [19,20] electric field, [21] and light. [18,22] The toxic nature of hybrid organic-inorganic lead halide perovskites has been traced to the presence of Pb in its chemical composition. [15,16,[23][24][25] Pb 2+ readily dissolves in water (e.g., rain water) to form a toxic solution capable of causing serious environmental pollution, harmful to human beings and the ecosystem. Besides their sensitivity to moisture, oxygen, light, electric field, or thermal stress, an existing self-degradation pathway [26,27] is also a big issue in hybrid organic-inorganic lead halide perovskites. Mixed-halide and mixed-cation perovskites have been investigated to address these issues. [28][29][30][31][32] The group IV elements, tin (Sn) [23,[33][34][35] and germanium (Ge), [34,36] have been employed as the replacements for Pb. However, the device performance through this approach has fallen short of the Pb-based ones. For example, the PCEs reported for Sn-based perovskite solar cells are usually less than 10%. [23,[33][34][35][37][38][39][40] In addition, the easy oxidation of Sn and Ge from the +2 state to the +4 state due to their high energy 5s and 4s orbitals makes them less promising for application in stable and long-term PSCs. [41] High throughput calculations also demonstrate that these substitutions are likely to compromise the ideal optoelectronic properties of MAPbI 3 . [42,43] Furthermore, low dimensional (e.g., 2D, 1D, and 0D) perovskites have also been used to address the stability issues in PSCs. [44][45][46][47][48] Recently, a stabilized PCE of 21.7% resulting from a 2D/3D bilayer PSC was reported. [49] However, the highest certified PCE in a 2D-only planar PSC is 15.3%, [50] which is far below that of their 3D perovskite-based counterparts. It thus stimulates the interest to develop new classes of materials which can solve the issues of toxicity and stability while still maintaining the fascinating properties of lead-based perovskite materials.Recent theoretical calculations demonstrate that a halide double perovskite structure, A 2 B′B″X 6 , which could be formed through a replacement of two toxic Pb 2+ in the crystal lattice with a pair of nontoxic heterovalent (i.e., monovalent and trivalent) metal cations, is a promising alternative to realize high-performance, lead-free, and stable PSCs. [51,52] Although, spectroscopic limited maximum efficiency (SLME) calculations revealed an efficiency limit less than 8% for the most prominent member www.advancedsciencenews.com double perovskites with a vacancy ordered structure. [88] In particular, the unit cell axis of Cs 2 AgBiBr 6 is given to be ≈11.25 Å, [25] which is two times larger than that of MAPbBr 3 (≈5.92 Å). [89] Both Ag + and Bi 3+ occupy the B-site of the crystal lattice with slightly varied metal-halide bond lengths. The dissimilar bond lengths st...

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“…Rand and co-workers found that, with the percentage of loadings of butylammonium (BA) no more than 20 mol% as compared to the molar amount of the 3D perovskites, the bulky BA cations only play the role of surface ligands that confines the growth rather than participate in the crystallization of the PNC grains. [55,88] Similarly, 3D PNCs of MAPbI 3 and MAPbBr 3 with 5.4 and 6.4 nm in size were also realized at an incorporation molar ratio of 20% with fluorophenylmethylammonium (FPMA) and PEA, respectively (Figure 5b). [89] At higher incorporation amount, however, multilayered RP phases begin to appear with the large OA cations intercalate into the crystal For the excess MABr case, a type I structure was formed with larger bandgap MABr (4.0 eV) and a smaller one for MAPbBr 3 (≈2.2 eV).…”

Section: Organic Ammonium Assisted In Situ Fabricationmentioning

confidence: 89%

“…Reproduced with permission. [17,51,53,59,67,78,88] Copyright 2014-2017, American Chemical Society; [57] Copyright 2015, American Association for the Advancement of Science; [58] Copyright 2012, The Chemical Society of Japan; [63,65] Copyright 2016, Springer Nature; [62,[70][71][72]117,121] Copyright 2015-2018, Wiley-VCH. mesostructured films through sol-gel treatment of TiO 2 and SiO 2 precursors within organic templating agents.…”

Section: Hard Template Assisted In Situ Fabricationmentioning

confidence: 99%

“…As mentioned above, the quasi 2D PNC structure can be denoted as L 2 A n−1 B n X 3n+1 . Plenty of investigations have been conducted on the choices of bulky cation L, including PEA, [56,63,64,[89][90][91][92] BA, [55,88,[93][94][95] ethylammonium (EA), [96] phenylmethylamine (PMA), [97] phenylbutylammonium (PBA), [98,99] naphthylmethylamine (NMA) [65,100] and 2-Phenoxyethylamine (POEA). [101] Similar to the pure 2D structure, with the space dimension reduced to nanosized 3D or quasi 2D, the PNCs exhibit strong excitonic behavior.…”

Section: Organic Ammonium Assisted In Situ Fabricationmentioning

confidence: 99%

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In Situ Fabricated Perovskite Nanocrystals: A Revolution in Optical Materials

Chang

Bai

Zhong

2018

Advanced Optical Materials

190

127

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in bulk halide perovskites, long carrier diffusion length, and an absorption range covering the visible solar spectrum, collectively enable the high performance of photo electricity conversion. Compared to the bulk materials, perovskite nanocrystals or quantum dots (usually denoted as PNCs or PQDs) show obvious excitonic features with enhanced photoluminescence (PL) properties due to the well-known size-dependent quantum confinement effects. [14][15][16][17] The combination of color saturated emissions, super high quantum yield (QY), as well as easy processing inspired the intensive exploration of PNCs as light emitters, which is now under spotlights in the field of optical materials.The first perspective aim of PNCs is to alternate the state-of-the-art CdSe or InP quantum dots (QDs) as new generation luminescence materials. [18,19] As shown in Figure 1, these QD materials have been well demonstrated to be potential functional components for photonic and optoelectronic applications, and are currently on the way to industrialization. [20][21][22][23] Specifically, QDs can be employed as fluorescence labels, [24] laser gain media, [25] LED phosphors, [26] and down-shifting films for LCD backlights. [27,28] They can also be processed into thin film for optoelectronic devices including solar cells, [29] photodetectors, [30,31] transistors [32] and LEDs. [33] The PNCs outcompete these conventional QDs in terms of narrower full width at half maximum (FWHM) and low fabrication cost, but most importantly, the ease of in situ preparation. [34,35] Herein, this progress report highlight the developments of in situ fabricated PNCs.Colloidal semiconductor QDs are typically synthesized ex situ in flasks by hot injection method, stabilized by surface ligands. [36][37][38][39] To incorporate such solution based materials into applications usually requires purification, redispersion and surface engineering. For instance, ligand exchange is often employed to disperse QDs into aimed solvent, inducing defects that inevitably derogating the PLQYs. [40] Moreover, the organic ligands themselves also suffer from the risk of disabsorbing, reducing the stability of the QDs and thus the final devices. [41] Because halide perovskite are ionic compounds that can be well dissolved into polar solvents, PNCs can be fabricated through either ex situ routes in flask or in situ strategies on substrates. The in situ fabricated PNCs are adaptable to devices integration due to their scalable and low-cost manufacturing. In this regard, more and more efforts have been made in terms of the controlling synthesis, physical properties and device applications of PNC materials.After over 30 years of development, colloidal quantum dots have now become mature luminescent materials in photonic and optoelectronic operations and start to hit the market. The emerging perovskite nanocrystals are expected to promote large-scale commercialization due to their superior optical properties as well as low cost and easy fabrication. This progress report is focused on the...

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Mixed-Halide Perovskites with Stabilized Bandgaps

Cited by 178 publications

References 29 publications

Inorganic CsPbI₂Br Perovskite Solar Cells: The Progress and Perspective

Inorganic CsPbI₂Br Perovskite Solar Cells: The Progress and Perspective

Progress of Lead‐Free Halide Double Perovskites

In Situ Fabricated Perovskite Nanocrystals: A Revolution in Optical Materials

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Mixed-Halide Perovskites with Stabilized Bandgaps

Cited by 178 publications

References 29 publications

Inorganic CsPbI2Br Perovskite Solar Cells: The Progress and Perspective

Inorganic CsPbI2Br Perovskite Solar Cells: The Progress and Perspective

Progress of Lead‐Free Halide Double Perovskites

In Situ Fabricated Perovskite Nanocrystals: A Revolution in Optical Materials

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Inorganic CsPbI₂Br Perovskite Solar Cells: The Progress and Perspective

Inorganic CsPbI₂Br Perovskite Solar Cells: The Progress and Perspective