Phase Engineering in Quasi-2D RuddlesdenâPopper Perovskites

Subscriber access provided by Kaohsiung Medical University

Perspective

Phase Engineering in Quasi-2D Ruddlesden–Popper Perovskites Yani Chen, Shuang Yu, Yong Sun, and Ziqi Liang J. Phys. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acs.jpclett.8b00840 • Publication Date (Web): 30 Apr 2018 Downloaded from http://pubs.acs.org on May 1, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The Journal of Physical Chemistry Letters

Phase Engineering in Quasi-2D Ruddlesden– Popper Perovskites Yani Chen, Shuang Yu, Yong Sun, and Ziqi Liang* Department of Materials Science, Fudan University, Shanghai 200433, China ABSTRACT: Quasi-2D Ruddlesden–Popper (RP) halide perovskites have drawn intensive research interest because they possess superior ambient stability while retaining the excellent device performance as compared to their pure 2D or 3D counterparts. By phase engineering strategy, quasi-2D perovskites can fall into three typeslarge-n 2D perovskite, 2D:3D mixed perovskite and 3D/2D bilayer perovskite. This article discusses the modulation of phase composition, hierarchical distribution and crystal orientation in quasi-2D perovskites, aiming to uncover the correlation between morphological structure, band alignment and charge recombination. A perspective of phase engineering in 2D RP-type perovskite materials is then given towards the concurrent stability and device efficiency. TOC GRAPHICS

KEYWORDS quasi-2D perovskites, Ruddlesden-Popper, phase engineering, solar cells, charge transport 1 ACS Paragon Plus Environment

The Journal of Physical Chemistry Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Owing to their superior ambient stability, two-dimensional (2D) Ruddlesden–Popper (RP) organometallic perovskites have recently attracted rapidly increasing attention. As displayed in Figure 1, The general chemical formula for 2D RP-type perovskites is L2An−1BnX3n+1 where A is a conventional monovalent cation (= CH3NH3+, HC(NH2)2+, Cs+, etc.) that is located into inorganic [BX6]4− octahedron while L is a larger aromatic or aliphatic alkylammonium organic spacer cation (= 2-phenylethylammonium (PEA), n-butylammonium (n-BA), etc.) that tailors the 3D perovskite into layered 2D structures, B is a divalent metal cation (= Pb2+, Sn2+, Ge2+, Cu2+, etc.), X is a halide anion (= Cl−, Br−, or I−), and the variable n (= 1, 2, 3, 4…) represents the number of inorganic lattices within each quantum well. As such, 2D perovskites enable to readily tailor the optical bandgap and absorption by varying either the spacer cation structure or the variable n while the organic spacer largely increases stability against oxygen and moisture.13 Recent a few years have witnessed the tremendous development in 2D perovskites based solar cells. Their power conversion efficiency (PCE) has rapidly increased from ~4%4,5 in 2014 to 13.7% in 2017 through either optimized fabrication (hot-casting technique) or composition engineering (Cs-inclusion method).6,7 However, such performance is remarkably worse than that of 3D analogues (up to 22.7%),8 which can be attributed to the hindered charge transport by the insulating nature of inserted long organic spacer and the random packing of crystals in 2D perovskites. Of particular relevance is that the nominal 2D perovskites are a mixture of phases with different quantum well widths. Yet there lacks of effective means to regulate the ratio and 2 ACS Paragon Plus Environment

Page 2 of 17

Page 3 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


hierarchical distribution of mixed phases to achieve favorable band alignment and charge transport. Notably, a multitude of research groups have successfully fabricated 3D/2D perovskite hybrids, resulting in a new era of perovskite research for high-efficiency thin film photovoltaics with superior air stability.928 These dimensionally mix-phased perovskites are denoted as quasi-2D perovskites. By far, as shown in Figure 1, there are mainly three routes to create them: 1) increasing the number of the inorganic lattices in the precursors (Figure 1a), 2) mixing 2D and 3D perovskites in solution, which involves both one-step and two-step processing methods (Figure 1b), 3) depositing a thin layer of 2D perovskite from solution on top of 3D perovskite thin film to generate the 3D/2D bilayer structures (Figure 1c).

Figure 1. Schematic of three type quasi-2D perovskites: (a) large-n 2D perovskite, (b) 2D:3D mixed perovskite and (c) 3D/2D bilayer perovskite.

This perspective will firstly present the synthesis, energetic structures, optical properties and carrier dynamics of quasi-2D perovskites. Next, the above-mentioned three types of quasi-2D perovskites will be discussed and compared. Finally, the outlook of these hybrid perovskites in optoelectronic devices will be given and a critical perspective is offered to guide the design of novel perovskite structures.

3 ACS Paragon Plus Environment


For the n-modulating strategy, it requires a delicate control of n-values in 2D perovskites to compromise between the efficiency and stability in device. Varying the Thickness of Inorganic Lattices (n). With the increase of n value from 1 to ∞, the perovskite structure undergoes the dimensional evolution, which transits gradually from pure 2D phases to 3D:2D mixtures and finally 3D perovskites, as schematically shown in Figure 2a. It has been reported that the structures and properties of perovskites varied with n value. For example, for (PEA)2MAn-1PbnI3n+1 perovskite, the formation energy increased with decreasing n value, suggesting the enhanced air stability.9 Moreover, the energy bandgaps (Egs) increased linearly with decreasing quantum-well thickness (i.e., n value), giving Eg 1/n at n > 2.10 Meanwhile the dielectric constants ascended largely with n, thus lowering exciton binding energy (Eb). Furthermore, structural transformation from 2D to 3D phase brought about slightly diminished effective mass of electrons (mc) and holes (mv), indicating that the layer thickness (n) has negligible effect on the mobility of photogenerated carriers. Later, Barea et al. investigated the influence of n values on exciton splitting.11 It was found that there are no quantum confinement effect in the RP halide perovskites with n > 3, which can be confirmed by the absence of emission or absorption shifts from UV−vis and electroluminescence spectra. This phenomenon is similar to that of 3D bulk counterpart so that RP perovskites with n > 3 can be effectively applied to solar cells. As a demonstration, (CHMA)2(MA)n−1PbnI3n+1 with n = 1−5 based solar cells were compared in device performance.12 When n < 3, the PCE barely exceeded 0.1% while it raised up to ~4% when n ≥ 4. Remarkably, the Etgar group synthesized layered 4 ACS Paragon Plus Environment

Page 4 of 17

Page 5 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


perovskites with very large n values (n = 40, 50, 60) which exhibited higher open-circuit voltage (VOC) and PCE (~8.5%) than 3D counterparts.13 On the other hand, the Sargent group showed that a utilization of allylammonium ligand enabled a narrower distribution of QW widths (n = 10), thus creating a flattened energy landscape that led to ×1.4 and ×1.9 longer diffusion lengths for electrons and holes, respectively.14 In addition, the n value impacts greatly on the crystal orientation of 2D perovskites. For instance, the (BA)2(MA)n−1PbnI3n+1 2D perovskite crystals were preferentially aligned parallel to the substrate when n = 1 and turned nearly perpendicular when n = 4.15 In short, when n is small, the ambient stability can be guaranteed in RP perovskites owing to the dominant contribution of hydrophobic spacing cations while the charge carrier transportation is hindered, and vice versa. There is always a trade-off between device performance and stability, as indicated in Figure 2b. It is therefore necessary to determine the optimal n-value in RP perovskites to compromise between the efficiency and stability in device.



Figure 2. (a) Schematic of 2D (PEA)2MAn-1PbnI3n+1 perovskite structures with varying n value from 1 to ∞. (b) The device performance and stability variation of PCE with n value. Reprinted with permission from ref 9. Copyright 2016 American Chemical Society.

Morphological randomness of 2D:3D mixed perovskites increases the difficulties of device optimization and bench-to-bench reproduction. 2D:3D Mixed Perovskites. For the above n-modulating strategy, it is however inevitable to generate super-small-n 2D phases (n < 3) that impede charge/energy transfer process, even when the starting n value in precursor solution is very large. This can be compensated by the presence of 3D phases with favorable charge transportation, which may be formed via self-assembly to some degree yet in an uncontrollable way. In order to attain a delicate control of 3D phases, several research groups have recently 6 ACS Paragon Plus Environment

Page 6 of 17

Page 7 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


generated devices based on a mixture of 2D and 3D perovskites.1620 There are two typical routes towards 2D:3D mixed perovskites. One is ‘one-step’ method that blends the precursors of 2D and 3D perovskites in solution for spin-coating while the other is ‘two-step’ deposition that spin-casts the mixed solution of organic cation (A) and spacer cation (L) on the top of PbI2 layer. In the former method, the Snaith group added n-BA+ into benchmark 3D perovskites of mixed-cation/halide FA0.83Cs0.17Pb(IyBr1−y)3.16 The resulting mixture based solar cells exhibited a stabilized PCE of ~17.5 %. It is interesting to note that the 2D phases tended to intersperse between highly oriented 3D perovskite grains, resulting in suppressed nonradiative charge recombination. This phenomena was also found in NH2C4H9COOH (termed as Ava) spacer dication incorporated MAPbI3 based quasi-2D perovskite.17 Zhao et al. recently introduced this Ava dication into 3D MAPbBr3 perovskite to form NH3C4H9COO(CH3NH3)nPbnBr3n where the protonated NH3+ groups displaced the MA+ while the COO− groups took the place of unoccupied Pb2+, thereby promoting the formation of smooth planar films with a notably high PLQY up to ~80%.18 More recently, they reported another organic spacerethylenediamine (EDA), bearing double-active sites, based quasi-2D perovskites.19 It was found that the addition of EDAPbI4 aided to avoid the formation of the undesirable non-perovskite δ phase, which can be attributed to the cross-linking capability of EDA. As a result, the devices based on CsPbI3ꞏ0.025EDAPbI4 perovskite yielded a PCE of 11.8% with excellent stability at room temperature for months. On the other hand, Jen and his coworkers for the first time employed the two-step deposition to introduce phenylethylammonium iodide (PEAI) into FAPbI3 perovskite 7 ACS Paragon Plus Environment


and generate quasi-2D FAxPEA1−xPbI3 structures.20 The PEA+ ions around the crystal grain boundaries presented dual functionsi) tighten FAPbI3 domains via migrating into the FAPbI3 grain boundaries to form organic shells with induced π–π interaction and ii) raise the phase transition energy and passivate the surface to improve both phase and moisture stability. The resulting 2D-quasi perovskite solar cells gave a high PCE of 17.7% with superior phase stability in air. In the above 2D:3D mixed perovskites, however, it is highly difficult to determine their n values as illustrated in Figure 3 that displays three possible band structure alignments. It is more likely for those mixed perovskites to exhibit a random distribution of 2D and 3D phases (Figure 3a), which leads to mismatched band alignment and thus unfavorable charge recombination, than achieve favorably flat or ordered band alignments (Figure 3b,c).

Figure 3. Schematic band alignment in 3D:2D mixed perovskites in (a) random, (b) flat and (c) ordered fashions. 3D/2D Bilayer Perovskites. In order to resolve the random band alignment in the above 2D:3D mixed perovskites, the 3D/2D bilayer heterojunction structure has received exponentially increasing attention. Such structure can be formed by cation 8 ACS Paragon Plus Environment

Page 8 of 17

Page 9 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


exchange method in solution-cast or through thermal evaporation.2128 On the other hand, such heterostructures can be varied by modifying the composition of precursors. For example, the Huang group investigated the chemical reaction mechanism of forming 3D/2D stacking structures.21 They compared two kinds of precursor solution for cation-exchangeby means of either BA dissolved in chlorobenzene (CB) or 2) BAI dissolved in isopropyl alcohol (IPA), as shown in eqs 1 and 2, respectively. The resulting 2D perovskites possessed distinctive compositions and phases. Intriguingly, reversible conversions can be obtained by such cation exchange reactions with BAI (3D to 2D) or MAI (2D to 3D) solutions. 2BA + MAI + MAPbI3 → (BA)2PbI4 + 2MA↑

(1)

2BAI + nMAPbI3 ↔ (BA)2(MA)n-1PbnI3n+1 + MAI

(2)

The solar cell applications of such 3D/2D bilayered structures were initiated by the Pablo group.22 They fabricated 3D/2D bilayer perovskite based solar cells by cation infiltration method that spin-coated a layer of mixed PEAI:MAI or BAI:MAI in IPA solution on the top of MAPbI3 layer. As shown in Figure 4a, the partial reorientation of crystallites occurred upon the formation of the PEAMAPI layer, thereby yielding a PCE of 16.84% in solar cells. The same result of such ordered band alignment was also found in MAPbI3/(BA)2(MA)n−1PbnI3n+1 3D/2D bilayers by the Jin group using static and transient spectroscopic measurements.23 Multiple perovskite phases were arranged in the sequence order of their n values along the direction perpendicular to the substrate. Carrier transfer within the unique superstructure occurred most likely from the small-n to the large-n phase.24 Moreover, the optimal alignment of graded energy bands 9 ACS Paragon Plus Environment


provided a continuous upshift of the LUMO level in 3D/2D perovskite structure, which facilitated charge transfer from perovskite to the electron-transporting layer (ETL) and also prevented the backflow of electron carriers, thus suppressing both charge recombination and ion migration (Figure 4b,c).25,26

Figure 4. (a) Schematic interpretation of the surface reorganization of MAPI films upon the PEAMAPI formation. Adapted from ref 22. Copyright 2016 by the American Chemical Society. (b) Energy level alignment at the interface of MAPbI3/PCBM. Reprinted from ref 25. Copyright 2017 by the Wiley-VCH. (c) The proposed thermal degradation routes of different devices. Reprinted with permission from ref 25. Copyright 2017 by the Wiley-VCH. Alternately, this bilayer structure has manifested as an effective strategy to fabricate high-quality Pb-free perovskite films for achieving promising photovoltaic performance. For instance, when a PEAI layer was thermally evaporated onto the FASnI3 thin film, the oxidation of the Sn2+ can be effectively avoided even in the


Page 10 of 17

Page 11 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


absence of reductant additive such as SnF2 and hydrazine.28 As a result, the resulting solar cells exhibited a promising PCE of 6.98% with good reproducibility. 3D/2D bilayer perovskite structure appears to be the most viable avenue to significantly improved air stability without notably sacrificing PCEs. Table 1 summarizes the up-to-date device performance of 3D/2D bilayer perovskites based solar cells. It is worth noting that the most adopted 3D perovskite in Table 1 is MAPbI3, for which a further enhancement of PCEs can be realized by using mixed-cation or halide similar to the avenues in pure 3D counterpart.26 For instance, an ultrahigh PCE up to 18.51% was acquired for MAPbI3/PEA2Pb2I4 planar solar cells.5 Also, an inclusion of Cs in 3D phase improved the photovoltaic performance yet reduced the device stability because the different ionic radius of two cations created strains within the bilayer perovskite structure.27 Table 1. Device performance of 3D/2D bilayer perovskites based solar cells 3D/2D Bilayer

Device

Jsc

Voc

Structure

Configuration

(mA/cm2)

(V)

FF

PCE (%)

FTO/NiO/ MAPbI3/PEA2Pb2I4

60%/30 d,

perovskite

21.80

1.17

0.78

19.89

25

BAMAPI

MAPbI3/(BA)2PbI4 or (BA)2(MA)n−1PbnI3n+1

FTO/c-TiO2/

18.63

perovskite/spiroOMeTAD/Au ITO/PTAA/

MAPbI3/(BA)2(MA)n−1

1.08

0.73

14.9422 22

16.56

1.08

0.62

11.49

22.49

1.11

0.78

19.5621

perovskite/PCBM/ C60/BCP/Cu

MAPbI3/ (PEA)2(MA)n−1PbnI3n+1 w/o 10% Cs

RH 20−30%

/PCBM/PN4N/Ag MAPbI3/PEAMAPI or

Stability

FTO/TiO2/ perovskite/ spiro-OMeTAD/Au

22.59

1.09

0.77

18.8521

24.0

0.90

0.59

12.6a27

20.8

0.86

0.56

9.9b27

21.4

0.86

0.55

10.2a27

20.6

0.85

0.57

10.0b27


76%/19 d, RH 75% 96.5%/ 100 h 88.2%/heat for 100 h N/A

N/A


PbnI3n+1 or (CHMA)2(MA )n−1Pbn I3n+1 w/o 10% Cs Cs0.05(FA0.83MA0.17)0.95Pb (I0.83Br0.17)3/PEA2PbI4

Page 12 of 17

21.9

0.86

0.54

10.6a27

20.4

0.86

0.59

10.2b27

22.89

1.11

0.73

18.5126

20.07

0.47

0.74

6.9826

FTO/c-TiO2/m-TiO2 /perovskite/spiroOMeTAD/Au

N/A

90%/1000h, RH 6010%

ITO/PEDOT:PSS/ FASnI3/(PEA,FA)SnI3

perovskite/C60/BCP/

N/A

Ag Note that JSC: short-circuit current density; VOC: open-circuit voltage; FF: fill factor; a: with 10% Cs; b: without 10% Cs.

Conclusions and Outlook. The original motive of developing Ruddlesden–Popper 2D structures for perovskite solar cells is to improve the ambient stability with the aid of additionally inserted hydrophobic cations. The resultant 2D perovskites present the anisotropic structural features, in particular microscopic structures including phase separation and crystal orientation, which play a determining role in solar cells by influencing light harvest, charge transport and device stability as compared with the 3D counterparts. This has been widely proved by both experimental studies and fundamental mechanistic investigations in recent years.915 Therefore, we believe that phase engineering would be the core issue in the upcoming research of 2D RP perovskites based solar cells. In this context, 3D/2D bilayer perovskites have demonstrated the great potential where the superior photovoltaic performance of 3D perovskites and the enhanced stability of 2D perovskites are complementary. Despite the promising published results, there remains great challenges in this direction: How to derive the relationship between the charge carrier dynamics and the morphological structures in quasi-2D perovskites? How to improve the electronic coupling between 2D and 3D at their interfaces? How to simplify the processing procedures while 12 ACS Paragon Plus Environment

Page 13 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


maintaining the reproducibility of device performance? These are the most urgent issues waiting to be resolved in the near future. AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected] Notes The authors declare no competing financial interests. ACKNOWLEDGMENTS This work was supported by Inter-Governmental International Cooperation Project of Science and Technology Commission of Shanghai Municipality (STCSM) under grant No. 17520710100 (Z.L.). REFERENCES (1) Chen, Y.; Sun, Y.; Peng, J.; Tang, J.; Zheng, K.; Liang, Z. 2D Ruddlesden−Popper Perovskites for Optoelectronics. Adv. Mater. 2018, 30, 1703487. (2) Pedesseau, L.; Sapori, D.; Traore, B.; Robles, R.; Fang, H. H.; Loi, M. A.; Tsai, H.; Nie, W.; Blancon, J. C.; Neukirch, A.; Tretiak, S.; Mohite, A. D.; Katan, C.; Even, J.; Kepenekian, M. Advances and Promises of Layered Halide Hybrid Perovskite Semiconductors. ACS Nano 2016, 10, 9776−9786. (3) Etgar, L. The Merit of Perovskite's Dimensionality: Can This Replace The 3D Halide Perovskite? Energy Environ. Sci. 2018, 11, 234−242. (4) Smith, I. C.; Hoke, E. T.; Solis-Ibarra, D.; McGehee, M. D.; Karunadasa, H. I. A Layered Hybrid Perovskite Solar-Cell Absorber with Enhanced Moisture Stability. Angew. Chem. Int. Ed. 2014, 53, 11232−11235. (5) Cao, D. H.; Stoumpos, C. C.; Farha, O. K.; Hupp, J. T.; Kanatzidis, M. G. 2D Homologous Perovskites as Light-Absorbing Materials for Solar Cell Applications. J. 13 ACS Paragon Plus Environment


Am. Chem. Soc. 2015, 137, 7843−7850. (6) Tsai, H.; Nie, W.; Blancon, J. C.; Stoumpos, C. C.; Asadpour, R.; Harutyunyan, B.; Neukirch, A. J.; Verduzco, R.; Crochet, J. J.; Tretiak, S.; Pedesseau, L.; Even, J.; Alam, M. A.; Gupta, G.; Lou, J.; Ajayan, P. M.; Bedzyk, M. J.; Kanatzidis, M. G. HighEfficiency Two-Dimensional Ruddlesden-Popper Perovskite Solar Cells. Nature 2016, 536, 312−316. (7) Zhang, X.; Ren, X.; Liu, B.; Munir, R.; Zhu, X.; Yang, D.; Li, J.; Liu, Y.; Smilgies, D.-M.; Li, R.; Yang, Z.; Niu, T.; Wang, X.; Amassian, A.; Zhao, K.; Liu, S. Stable High Efficiency Two-Dimensional Perovskite Solar Cells via Cesium Doping. Energy Environ. Sci. 2017, 10, 2095−2102. (8) Best Research Cell Efficiencies: https://www.nrel.gov/pv/assets/images/efficiencychart.png (Updated in October 2017). (9) Quan, L. N.; Yuan, M.; Comin, R.; Voznyy, O.; Beauregard, E. M.; Hoogland, S.; Buin, A.; Kirmani, A. R.; Zhao, K.; Amassian, A.; Kim, D. H.; Sargent, E. H. LigandStabilized Reduced-Dimensionality Perovskites. J. Am. Chem. Soc. 2016, 138, 2649– 2655. (10) Zhang, L.; Liang, W. How the Structures and Properties of Two-Dimensional Layered Perovskites MAPbI3 and CsPbI3 Vary with The Number of Layers. J. Phys. Chem. Lett. 2017, 8, 1517−1523. (11) Rodríguez-Romero, J. s.; Hames, B. C.; Mora-Seró, I. n.; Barea, E. M. Conjugated Organic Cations to Improve the Optoelectronic Properties of 2D/3D Perovskites. ACS Energy Lett. 2017, 2, 1969–1970. 14 ACS Paragon Plus Environment

Page 14 of 17

Page 15 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(12) Koh, T. M.; Huang, J.; Neogi, I.; Boix, P. P.; Mhaisalkar, S. G.; Mathews, N. High Stability Bilayered Perovskites through Crystallization Driven Self-Assembly. ACS Appl. Mater. Interfaces 2017, 9, 28743−28749. (13) Cohen, B.-E.; Wierzbowska, M.; Etgar, L. High Efficiency and High Open Circuit Voltage in Quasi 2D Perovskite Based Solar Cells. Adv. Funct. Mater. 2017, 27, 1604733. (14) Proppe, A. H.; Quintero-Bermudez, R.; Tan, H.; Voznyy, O.; Kelley, S. O.; Sargent, E. H. Synthetic Control over Quantum Well Width Distribution and Carrier Migration in Low-Dimensional Perovskite Photovoltaics. J. Am. Chem. Soc. 2018, 140, 2890−2896. (15) Venkatesan, N. R.; Labram, J. G.; Chabinyc, M. L. Charge-Carrier Dynamics and Crystalline Texture of Layered Ruddlesden–Popper Hybrid Lead Iodide Perovskite Thin Films. ACS Energy Lett. 2018, 3, 380−386. (16) Wang, Z.; Lin, Q.; Chmiel, F. P.; Sakai, N.; Herz, L. M.; Snaith, H. J. Efficient Ambient-Air-Stable Solar Cells with 2D–3D Heterostructured ButylammoniumCaesium-Formamidinium Lead Halide Perovskites. Nat. Energy 2017, 2, 17135. (17) Grancini, G.; Roldán-Carmona, C.; Zimmermann, I.; Mosconi, E.; Lee, X.; Martineau, D.; Narbey, S.; Oswald, F.; Angelis, F. D.; Graetzel, M.; Nazeeruddin, M. K. One-Year Stable Perovskite Solar Cells by 2D/3D Interface Engineering. Nat. Commun. 2017, 8, 15684. (18) Zhang, T.; Xie, L.; Chen, L.; Guo, N.; Li, G.; Tian, Z.; Mao, B.; Zhao, Y. In Situ Fabrication of Highly Luminescent Bifunctional Amino Acid Crosslinked 2D/3D 15 ACS Paragon Plus Environment


NH3C4H9COO(CH3NH3PbBr3)n Perovskite Films. Adv. Funct. Mater. 2017, 27, 1603568. (19) Zhang, T.; Dar, M. I.; Li, G.; Xu, F.; Guo, N.; Grätzel, M.; Zhao, Y. Bication Lead Iodide 2D Perovskite Component to Stabilize Inorganic a-CsPbI3 Perovskite Phase for High-Efficiency Solar Cells. Sci. Adv. 2017, 3, e1700841. (20) Li, N.; Zhu, Z.; Chueh, C.-C.; Liu, H.; Peng, B.; Petrone, A.; Li, X.; Wang, L.; Jen, A. K.-Y. Mixed Cation FAxPEA1–xPbI3 with Enhanced Phase and Ambient Stability toward High-Performance Perovskite Solar Cells. Adv. Energy Mater. 2017, 7, 1601307. (21) Lin, Y.; Bai, Y.; Fang, Y.; Chen, Z.; Yang, S.; Zheng, X.; Tang, S.; Liu, Y.; Zhao, J.; Huang, J. Enhanced Thermal Stability in Perovskite Solar Cells by Assembling 2D/3D Stacking Structures. J. Phys. Chem. Lett. 2018, 9, 654−658. (22) Hu, Y.; Schlipf, J.; Wussler, M.; Petrus, M. L.; Jaegermann, W.; Bein, T.; MüllerBuschbaum, P.; Docampo, P. Hybrid Perovskite/Perovskite Heterojunction Solar Cells. ACS Nano 2016, 10, 5999−6007. (23) Wang, J.; Leng, J.; Liu, J.; He, S.; Wang, Y.; Wu, K.; Jin, S. Engineered Directional Charge Flow in Mixed Two-Dimensional Perovskites Enabled by Facile CationExchange. J. Phys. Chem. C 2017, 121, 21281−21289. (24) Li, L.; Zhou, N.; Chen, Q.; Shang, Q.; Zhang, Q.; Wang, X.; Zhou, H. Unraveling the Growth of Hierarchical Quasi-2D/3D Perovskite and Carrier Dynamics. J. Phys. Chem. Lett. 2018, 9, 1124−1132. (25) Bai, Y.; Xiao, S.; Hu, C.; Zhang, T.; Meng, X.; Lin, H.; Yang, Y.; Yang, S. 16 ACS Paragon Plus Environment

Page 16 of 17

Page 17 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Dimensional Engineering of a Graded 3D–2D Halide Perovskite Interface Enables Ultrahigh VOC Enhanced Stability in The p-i-n Photovoltaics. Adv. Energy Mater. 2017, 7, 1701038. (26) Chen, P.; Bai, Y.; Wang, S.; Lyu, M.; Yun, J.; Wang; L. In Situ Growth of 2D Perovskite Capping Layer for Stable and Efficient Perovskite Solar Cells. Adv. Funct. Mater. 2018, 28, 1706923. (27) Iagher, L.; Etgar, L. Effect of Cs on the Stability and Photovoltaic Performance of 2D/3D Perovskite-Based Solar Cells. ACS Energy Lett. 2018, 3, 366−372. (28) Ran, C.; Xi, J.; Gao, W.; Yuan, F.; Lei, T.; Jiao, B.; Hou, X.; Wu, Z. Bilateral Interface Engineering toward Efficient 2D–3D Bulk Heterojunction Tin Halide LeadFree Perovskite Solar Cells. ACS Energy Lett. 2018, 3, 713−721.


Phase Engineering in Quasi-2D RuddlesdenâPopper Perovskites

Recommend Documents

Phase Engineering in Quasi-2D RuddlesdenâPopper Perovskites