Extremely reduced dielectric confinement in two-dimensional hybrid perovskites with large polar organics

Bin Cheng, Ting You Li, Partha Maity, Pai Chun Wei, Dennis Nordlund, Kang Ting Ho, Der-Hsien Lien, Chun Ho Lin, Ru Ze Liang, Xiaohe Miao, Idris A. Ajia, Jun Yin, Dimosthenis Sokaras, Ali Javey, Iman S. Roqan, Omar F. Mohammed, Jr Hau He*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

135 Scopus citations


Two dimensional inorganic–organic hybrid perovskites (2D perovskites) suffer from not only quantum confinement, but also dielectric confinement, hindering their application perspective in devices involving the conversion of an optical input into current. In this report, we theoretically predict that an extremely low exciton binding energy can be achieved in 2D perovskites by using high dielectric-constant organic components. We demonstrate that in (HOCH2CH2NH3)2PbI4, whose organic material has a high dielectric constant of 37, the dielectric confinement is largely reduced, and the exciton binding energy is 20-times smaller than that in conventional 2D perovskites. As a result, the photo-induced excitons can be thermally dissociated efficiently at room temperature, as clearly indicated from femtosecond transient absorption measurements. In addition, the mobility is largely improved due to the strong screening effect on charge impurities. Such low dielectric-confined 2D perovskites show excellent carrier extraction efficiency, and outstanding humidity resistance compared to conventional 2D perovskites.

Original languageEnglish
Article number80
Pages (from-to)1-8
Number of pages8
JournalCommunications Physics
Issue number1
StatePublished - 1 Dec 2018


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