Ultrafast Excitonic Response in Two-Dimensional Hybrid Perovskites Driven by Intense Midinfrared Pulses

Li，Shunran1,2; Li，Xiaotong3; Kocoj，Conrad A.1,2; Ji，Xiaoqin4; Yuan，Shaofan5; Macropulos，Eleni C.6; Stoumpos，Constantinos C.6; Xia，Fengnian5; Mao，Lingling4; Kanatzidis，Mercouri G.3; Guo，Peijun1,2

2022-10-21

10.1103/PhysRevLett.129.177401

PHYSICAL REVIEW LETTERS   Impact Factor & Quartile

0031-9007

1079-7114

Two-dimensional organic-inorganic hybrid perovskites (2DHPs) are natural quantum-well-like materials, in which strong quantum and dielectric confinement effects due to the organic spacers give rise to tightly bound excitons with large binding energy. To examine the mutual interactions between the organic spacer cations and the inorganic charge-residing octahedral framework in 2DHPs, here we perform femtosecond pump-probe spectroscopy by direct vibrational pumping of the organic spacers, followed by a visible-to-ultraviolet probe covering their excitonic resonances. Measurements on prototypical lead-bromide based 2DHP compounds, (BA)2PbBr4 and (BA)2(FA)Pb2Br7 (BA+=butylammonium; FA+=formamidinium), reveal two distinct regimes of the temporal response. The first regime is dominated by a pump-induced transient expansion of the organic spacer layers that reduces the exciton oscillator strength, whereas the second regime arises from pump-induced lattice heating effects primarily associated with a spectral shift of the exciton energy. In addition, vibrational excitation enhances the biexciton emission, which we attribute to a stronger intralayer exciton confinement as well as vibrationally induced exciton detrapping from defect states. Our study provides fundamental insights regarding the impact of organic spacers on excitons in 2DHPs, as well as the excited-state dynamics and vibrational energy dissipation in these structurally diverse materials.

SCI

English

NI Journal Papers

Others

[FA9550-22-1-0209] ; [KA 10652] ; [SC0012541]

Physics

Physics, Multidisciplinary

WOS:000878635200004

AMER PHYSICAL SOC

PHYSICS

2-s2.0-85141235099

Scopus

1.Department of Chemical and Environmental Engineering,Yale University,New Haven,9 Hillhouse Avenue,06520,United States
2.Energy Sciences Institute,Yale University,West Haven,810 West Campus Drive,06516,United States
3.Department of Chemistry,Northwestern University,Evanston,2145 Sheridan Road,60208,United States
4.Department of Chemistry,Southern University of Science and Technology,Shenzhen,China
5.Department of Electrical Engineering,Yale University,New Haven,15 Prospect Street,06511,United States
6.Department of Materials Science and Technology,University of Crete,Voutes Campus,Heraklion,70013,Greece

Li，Shunran,Li，Xiaotong,Kocoj，Conrad A.,et al. Ultrafast Excitonic Response in Two-Dimensional Hybrid Perovskites Driven by Intense Midinfrared Pulses[J]. PHYSICAL REVIEW LETTERS,2022,129(17).

Li，Shunran.,Li，Xiaotong.,Kocoj，Conrad A..,Ji，Xiaoqin.,Yuan，Shaofan.,...&Guo，Peijun.(2022).Ultrafast Excitonic Response in Two-Dimensional Hybrid Perovskites Driven by Intense Midinfrared Pulses.PHYSICAL REVIEW LETTERS,129(17).

Li，Shunran,et al."Ultrafast Excitonic Response in Two-Dimensional Hybrid Perovskites Driven by Intense Midinfrared Pulses".PHYSICAL REVIEW LETTERS 129.17(2022).