Ultralow Self-Doping in 2D Hybrid Perovskite Single Crystals

Wei Peng, Jun Yin, Kang-Ting Ho, Olivier Ouellette, Michele de Bastiani, Murali Banavoth, Omar El Tall, Chao Shen, Xiaohe Miao, Jun Pan, Erkki Alarousu, Jr-Hau He, Boon S. Ooi, Omar F. Mohammed, Edward H. Sargent, Osman Bakr

Research output: Contribution to journalArticlepeer-review

248 Scopus citations

Abstract

Unintentional self-doping in semiconductors through shallow defects is detrimental to optoelectronic device performance. It adversely affects junction properties and it introduces electronic noise. This is especially acute for solution-processed semiconductors, including hybrid perovskites, which are usually high in defects due to rapid crystallization. Here, we uncover extremely low self-doping concentrations in single crystals of (C6H5C2H4NH3)2PbI4・(CH3NH3PbI3)n-1 (n=1, 2, and 3)—over three orders of magnitude lower than those of typical three-dimensional hybrid perovskites—by analyzing their conductivity behavior. We propose that crystallization of hybrid perovskites containing large organic cations suppresses defect formation and thus favors a low self-doping level. To exemplify the benefits of this effect, we demonstrate extraordinarily high light-detectivity (1013 Jones) in (C6H5C2H4NH3)2PbI4・(CH3NH3PbI3)n-1 photoconductors due to the reduced electronic noise, which makes them particularly attractive for the detection of weak light signals. Furthermore, the low self-doping concentration reduces the equilibrium charge carrier concentration in (C6H5C2H4NH3)2PbI4・(CH3NH3PbI3)n-1, advantageous in the design of p-i-n heterojunction solar cells by optimizing band alignment and promoting carrier depletion in the intrinsic perovskite layer, thereby enhancing charge extraction.
Original languageEnglish (US)
Pages (from-to)4759-4767
Number of pages9
JournalNano Letters
Volume17
Issue number8
DOIs
StatePublished - Jun 28 2017

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Financial support for this work was provided by KAUST. W.P. would like to acknowledge Chun Ma at KAUST for his valuable suggestions on the measurement of photodetector noise, Feng Li and Ting-You Li at KAUST for their assistance in measuring temperature-dependent conductivity.

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