Origin of the Enhanced Photoluminescence Quantum Yield in MAPbBr3 Perovskite with Reduced Crystal Size

Nikolaos Droseros, Giulia Longo, Jan C. Brauer, Michele Sessolo, Henk J. Bolink, Natalie Banerji*

*Corresponding author for this work

Research output: Contribution to journalLetterpeer-review

60 Citations (Scopus)
5 Downloads (Pure)

Abstract

Methylammonium lead bromide perovskite (MAPbBr3) has been widely investigated for applications in visible perovskite light-emitting diodes (LEDs). Fine-tuning of the morphology and of the crystal size, from the microscale down to the quantum confinement regime, has been used to increase the photoluminescence quantum yield (PLQY). However, the physical processes underlying the PL emission of this perovskite remain unclear. Here, we elucidate the origin of the PL emission of polycrystalline MAPbBr3 thin films by different spectroscopic techniques. We estimate the exciton binding energy, the reduced exciton effective mass, and the trap density. Moreover, we confirm the coexistence of free carriers and excitons, quantifying their relative population and mutual interaction over a broad range of excitation densities. Finally, the enhanced PLQY upon crystal size reduction to the micro- and nanometer scale in the presence of additives is attributed to favored excitonic recombination together with reduced surface trapping thanks to efficient passivation by the additives.

Original languageEnglish
Pages (from-to)1458-1466
Number of pages9
JournalACS Energy Letters
Volume3
Issue number6
Early online date21 May 2018
DOIs
Publication statusPublished - 8 Jun 2018
Externally publishedYes

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