Improving Charge Carrier Delocalization in Perovskite Quantum Dots by Surface Passivation with Conductive Aromatic Ligands

Evan T. Vickers, Thomas A. Graham, Ashraful H. Chowdhury, Behzad Bahrami, Benjamin W. Dreskin, Sarah Lindley, Sara Bonabi Naghadeh, Qiquan Qiao, Jin Z. Zhang

Research output: Contribution to journalArticlepeer-review

Abstract

Long-chain saturated hydrocarbons and alkoxysilanes are ligands that are commonly used to passivate perovskite quantum dots (PQDs) to enhance their stability and optical properties. However, the insulating nature of these capping ligands creates an electronic energy barrier and impedes interparticle electronic coupling, thereby limiting device applications. One strategy to solve this problem is the use of short conductive aromatic ligands that allow delocalization of the electronic wave function from the PQDs, which, in turn, facilitates charge transport between PQDs by lowering the energy barrier. This is demonstrated with methylammonium lead bromide (MAPbBr3) QDs prepared using benzylamine (BZA) and benzoic acid (BA) capping ligands. Optimized BZA-BA-MAPbBr3 QDs are highly stable and show very high photoluminescence (PL) quantum yield (QY) (86%). More importantly, the BZA-BA-MAPbBr3 QD film exhibits higher conductivity and carrier lifetime and more efficient charge extraction compared to PQDs with insulating ligands, as indicated by electrochemical measurements and transient photocurrent and photovoltage spectroscopy.

Original languageEnglish (US)
Pages (from-to)2931-2939
Number of pages9
JournalACS Energy Letters
Volume3
Issue number12
DOIs
StatePublished - Dec 14 2018
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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