Phase control for quasi-2D blue emitters by spacer cation engineering

Tam, Ho Won; Leung, Tik Lun; Sun, Wenting; Liu, Fangzhou; Ma, Chao; Kam, Chun Sing; Lončarić, Ivor; Grisanti, Luca; Ovčar, Juraj; Skoko, Željko; Popović, Jasminka; Đurišić, Aleksandra (2020) Phase control for quasi-2D blue emitters by spacer cation engineering. Journal of Materials Chemistry C, 8 . pp. 11052-11060. ISSN 2050-7526

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Official URL: https://doi.org/10.1039/D0TC01631D

Abstract

Effect of the alkylammonium tail length in phenyl-alkyl spacer cations in quasi-2D Ruddlesden-Popper perovskites on the phase distribution in low n films (n=2 stoichiometry) is investigated. The increase in the alkyl chain length suppresses the formation of n=1 phase (and consequently higher n phases), which is attributed to the change in the packing arrangement of spacer cations from parallel (one and two carbon atoms alkyl chain) to non- parallel (3 carbon atoms alkyl chain). Single blue emission peak corresponding to n=3 phase (466 nm) and n=2 phase (436 nm) is obtained in the PL spectra of propylphenylammonium quasi-2D perovskites with methylammonium (MA) and formamidinium (FA) cations, respectively. The same trends in phase distribution, namely the reduction in the proportion of n=1 phase with increasing alkyl chain length are observed for both MA- and FA- based perovskites. However, FA- based samples exhibit higher crystallinity but worsened morphology (more pinholes) and less efficient funneling compared to MA-based samples. Consequently, efficient sky-blue LEDs with the highest EQE of 3.35% are obtained for PPA2MAPb2Br7 perovskite.

Item Type:

Article

Uncontrolled Keywords:

Ruddlesden-Popper perovskites

Subjects:

NATURAL SCIENCES > Physics
NATURAL SCIENCES > Chemistry > Inorganic Chemistry

Divisions:

Division of Materials Physics
Theoretical Physics Division

Projects: