Decreasing the electronic confinement in layered perovskites through intercalation

Smith, Matthew D.; Pédesseau, Laurent; Képénékian, Mikaël; Smith, Ian C. P.; Katan, Claudine; Even, Jacky; Karunadasa, Hemamala I.

doi:10.1039/c6sc02848a

Cited by 127 publications

(188 citation statements)

References 59 publications

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“…Importantly,n either 1-I 2 or 1-N 2 /I 2 show evidence of iodine addition to triple or double bonds, [20] halide swap, [21] nor can the observed effects be explained by intercalation of I 2 . [22] Thespectroscopic similarities between 1-I 2 , 1-N 2 /I 2 ,and 1-O 2 suggest that partial oxidation of 1-N 2 is indeed responsible for the change in color.T ofurther confirm our hypothesis,we conducted solid-state X-band electron paramagnetic resonance (EPR) on samples of 1-as, 1-N 2 , 1-O 2 ,a nd 1-I 2 .E PR spectra of 1-as and 1-N 2 showed no signal whereas 1-O 2 and 1-I 2 showed as ignal at ag -value of 2.0033 and 2.0025, respectively (Figure 3a and S19 in the Supporting Information), both of which lie almost at the expected value for afree electron (2.0023) and clearly suggests the presence of an organic radical species within the material, which is most likely delocalized across the p-conjugated polydiacetylene.…”

Section: Two-dimensional (2d) Organic-inorganic Hybrid Perovskitesmentioning

confidence: 97%

Thousand‐fold Conductivity Increase in 2D Perovskites by Polydiacetylene Incorporation and Doping

et al. 2018

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Two-dimensional (2D) organic-inorganic perovskites have rapidly become an attractive alternative to traditional three-dimensional (3D) perovskite solar-cell absorbers owing to their improved stability and processability. Despite their advantages, the insulating nature of the organic cations and diminished light absorption limit their overall performance. Herein, it is demonstrated that the incorporation of conjugated diynes in hybrid 2D perovskites, and subsequent thermal treatment results in the formation of 2D perovskites that incorporate polydiacetylenes in their structure. Furthermore, it is shown that oxygen or iodine doping results in the formation of stable radicals within the material alongside a drastic shift of the band gap from 3.0 to 1.4 eV and in-plane conductivity improvements of up to three orders of magnitude, which lead to record conductivities for 2D halide perovskites (n=1).

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Section: Two-dimensional (2d) Organic-inorganic Hybrid Perovskitesmentioning

confidence: 97%

Thousand‐fold Conductivity Increase in 2D Perovskites by Polydiacetylene Incorporation and Doping

et al. 2018

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“…26,29,57 The reported values of the exciton binding energy are 467 meV and 490 meV (monolayer (C 4 H 9 NH 3 ) 2 PbI 4 ), against the 652 meV of our calculations. 26,29,58,59 In both cases the large value indicates strong excitonic effects, typical of 2D semiconductors. The difference in the value comes from the different dielectric screening.…”

Section: Excitonsmentioning

confidence: 99%

Excitonic States in Semiconducting Two-Dimensional Perovskites

Molina-Sánchez

2018

ACS Appl. Energy Mater.

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Hybrid organic/inorganic perovskites have emerged as efficient semiconductor materials for applications in photo-voltaic solar cells with conversion efficiency above 20 %. Recent experiments have synthesized ultra-thin two-dimensional (2D) organic perovskites with optical properties similar to those of 2D materials like monolayer MoS 2 : large exciton binding energy and excitonic effects at room temperature. In addition, 2D perovskites are synthesized with a simple fabrication process with potential low-cost and large-scale manufacture.Up to now, state-of-the-art simulations of the excitonic states have been limited to the study of bulk organic perovskites. The large number of atoms in the unit cell and the complex role of the organic molecules makes inefficient the use of ab initio methods. In this work, we define a simplified crystal structure to calculate the optical properties of 2D perovskites, replacing the molecular cations with inorganic atoms. We can thus apply state-of-the-art, parameter-free and predictive ab initio methods like the GW method and the Bethe-Salpeter equation to obtain the excitonic states of a model 2D perovskite. We find that optical properties of 2D perovskites are strongly influenced by excitonic effects, with binding energies up to 600 meV. Moreover, the 1 arXiv:1812.04332v1 [cond-mat.mtrl-sci] 11 Dec 2018 optical absorption is carried out at the bromine and lead atoms and therefore the results are useful for a qualitatively understanding of the optical properties of organic 2D perovskites. Cs 2 PbBr 4 MonolayerCsPbBr 3 Bulkz Cs-Cs < l a t e x i t s h a 1 _ b a s e 6 4 = " E L B U x g Q K 2 7 x V a 8 2 8 O E C E H 8 d 7 w 0 Y = " > A A A B + 3 i c b V B N S 8 N A E N 3 4 W e t X r E c v w S J 4 s S Q i 6 L H Y i 8 c K 9 g P a E D b b T b t 0 d x N 2 J 9 I a 8 l e 8 e F D E q 3 / E m / / G b Z u D t j 4 Y e L w 3 w 8 y 8 M O F M g + t + W 2 v r G 5 t b 2 6 W d 8 u 7 e / s G h f V R p 6 z h V h L Z I z G P M k m B S r J Y F K X c g d i Z B e E M m K I E + N Q Q T B Q z t z p k h B U m Y O I q m x C 8 5 Z d X S f u y 5 r k 1 7 / 6 q W r 8 t 4 i i h E 3 S K z p G H r l E d 3 a E m a i G C J u g Z v a I 3 K 7 d e r H f r Y 9 G 6 Z h U z x + g P r M 8 f j g i U w Q = = < / l a t e x i t > < l a t e x i t s h a 1 _ b a s e 6 4 = " E L B U x g Q K 2 7 x V a 8 2 8 O E C E H 8 d 7 w 0 Y = " > A A A B + 3 i c b V B N S 8 N A E N 3 4 W e t X r E c v w S J 4 s S Q i 6 L H Y i 8 c K 9 g P a E D b b T b t 0 d x N 2 J 9 I a 8 l e 8 e F D E q 3 / E m / / G b Z u D t j 4 Y e L w 3 w 8 y 8 M O F M g + t + W 2 v r G 5 t b 2 6 W d 8 u 7 e / s G h f V R p 6 z h V h L Z I z G P M k m B S r J Y F K X c g d i Z B e E M m K I E + N Q Q T B Q z t z p k h B U m Y O I q m x C 8 5 Z d X S f u y 5 r k 1 7 / 6 q W r 8 t 4 i i h E 3 S K z p G H r l E d 3 a E m a i G C J u g Z v a I 3 K 7 d e r H f r Y 9 G 6 Z h U z x + g P r M 8 f j g i U w Q = = < / l a t e x i t > < l a t e x i t s h a 1 _ b a s e 6 4 = " E L B U x g Q K 2 7 x V a 8 2 8 O E C E H 8 d 7 w 0 Y = " > A A A B + 3 i c b V B N S 8 N A E N 3 4 W e t X r...

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“…This gives rise to a complex disordered energy landscape, governed by both static and dynamic disorder, that depends on the structure imposed by the organic templating ligand. This makes the electronic characteristics of the material sensitive to the organic-inorganic lattice interactions, which have been previously considered in 2D HOIPs [7,[20][21][22][23]. However, fundamentally important questions remain concerning the role of the dynamic disorder on their ability to sustain strong excitonic multi-particle correlations as seen in other 2D materials.…”

Section: Introductionmentioning

confidence: 99%

Stable biexcitons in two-dimensional metal-halide perovskites with strong dynamic lattice disorder

Thouin

Neutzner

Cortecchia

et al. 2018

Phys. Rev. Materials

118

180

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With strongly bound and stable excitons at room temperature, single-layer, two-dimensional organic-inorganic hybrid perovskites are viable semiconductors for light-emitting quantum optoelectronics applications. In such a technological context, it is imperative to comprehensively explore all the factors -chemical, electronic and structural -that govern strong multi-exciton correlations.Here, by means of two-dimensional coherent spectroscopy, we examine excitonic many-body effects in pure, single-layer (PEA) 2 PbI 4 (PEA = phenylethylammonium). We determine the binding energy of biexcitons -correlated two-electron, two-hole quasiparticles -to be 44 ± 5 meV at room temperature. The extraordinarily high values are similar to those reported in other strongly excitonic two-dimensional materials such as transition-metal dichalchogenides. Importantly, we show that this binding energy increases by ∼ 25% upon cooling to 5 K. Our work highlights the importance of multi-exciton correlations in this class of technologically promising, solution-processable materials, in spite of the strong effects of lattice fluctuations and dynamic disorder. * FT and SN are to be considered first co-authors of this manuscript. †

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Decreasing the electronic confinement in layered perovskites through intercalation

Abstract: We show that post-synthetic small-molecule intercalation can significantly reduce the electronic confinement of 2D hybrid perovskites.

Cited by 127 publications

References 59 publications

Thousand‐fold Conductivity Increase in 2D Perovskites by Polydiacetylene Incorporation and Doping

Thousand‐fold Conductivity Increase in 2D Perovskites by Polydiacetylene Incorporation and Doping

Excitonic States in Semiconducting Two-Dimensional Perovskites

Stable biexcitons in two-dimensional metal-halide perovskites with strong dynamic lattice disorder

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