Origin of the Enhanced Photoluminescence Quantum Yield in MAPbBr 3 Perovskite with Reduced Crystal Size

Droseros, Nikolaos; Longo, Giulia; Brauer, Jan C.; Sessolo, Michele; Bolink, Henk J.; Banerji, Natalie (2018). Origin of the Enhanced Photoluminescence Quantum Yield in MAPbBr 3 Perovskite with Reduced Crystal Size. ACS energy letters, 3(6), pp. 1458-1466. American Chemical Society 10.1021/acsenergylett.8b00475

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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.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Droseros, Nikolaos and Banerji, Natalie

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry
500 Science > 530 Physics

ISSN:

2380-8195

Publisher:

American Chemical Society

Language:

English

Submitter:

Gareth John Moore

Date Deposited:

07 Dec 2018 13:01

Last Modified:

07 Dec 2018 13:01

Publisher DOI:

10.1021/acsenergylett.8b00475

BORIS DOI:

10.7892/boris.121527

URI:

https://boris.unibe.ch/id/eprint/121527

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