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Lead-free cesium titanium bromide double perovskite nanocrystals

Grandhi, G. Krishnamurthy ; Matuhina, Anastasia ; Liu, Maning LU orcid ; Annurakshita, Shambhavee ; Ali-Löytty, Harri ; Bautista, Godofredo and Vivo, Paola (2021) In Nanomaterials 11(6).
Abstract

Double perovskites are a promising family of lead-free materials that not only replace lead but also enable new optoelectronic applications beyond photovoltaics. Recently, a titanium (Ti)-based vacancy-ordered double perovskite, Cs2 TiBr6, has been reported as an example of truly sustainable and earth-abundant perovskite with controversial results in terms of photoluminescence and environmental stability. Our work looks at this material from a new perspective, i.e., at the nanoscale. We demonstrate the first colloidal synthesis of Cs2 TiX6 nanocrystals (X = Br, Cl) and observe tunable morphology and size of the nanocrystals according to the set reaction temperature. The Cs2... (More)

Double perovskites are a promising family of lead-free materials that not only replace lead but also enable new optoelectronic applications beyond photovoltaics. Recently, a titanium (Ti)-based vacancy-ordered double perovskite, Cs2 TiBr6, has been reported as an example of truly sustainable and earth-abundant perovskite with controversial results in terms of photoluminescence and environmental stability. Our work looks at this material from a new perspective, i.e., at the nanoscale. We demonstrate the first colloidal synthesis of Cs2 TiX6 nanocrystals (X = Br, Cl) and observe tunable morphology and size of the nanocrystals according to the set reaction temperature. The Cs2 TiBr6 nanocrystals synthesized at 185◦ C show a bandgap of 1.9 eV and are relatively stable up to 8 weeks in suspensions. However, they do not display notable photoluminescence. The centrosymmetric crystal structure of Cs2 TiBr6 suggests that this material could enable third-harmonic generation (THG) responses. Indeed, we provide a clear evidence of THG signals detected by the THG microscopy technique. As only a few THG-active halide perovskite materials are known to date and they are all lead-based, our findings promote future research on Cs2 TiBr6 as well as on other lead-free double perovskites, with stronger focus on currently unexplored nonlinear optical applications.

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author
; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Double perovskites, Lead-free halide perovskites, Nanocrystals, Nonlinear optics, Stability, Third-harmonic generation, Titanium (Ti)
in
Nanomaterials
volume
11
issue
6
article number
1458
publisher
MDPI AG
external identifiers
  • scopus:85107016093
ISSN
2079-4991
DOI
10.3390/nano11061458
language
English
LU publication?
no
id
357f5740-fd6a-4e6d-9458-aef82f3f0b0d
date added to LUP
2023-08-24 12:26:53
date last changed
2023-08-25 14:50:12
@article{357f5740-fd6a-4e6d-9458-aef82f3f0b0d,
  abstract     = {{<p>Double perovskites are a promising family of lead-free materials that not only replace lead but also enable new optoelectronic applications beyond photovoltaics. Recently, a titanium (Ti)-based vacancy-ordered double perovskite, Cs<sub>2</sub> TiBr<sub>6</sub>, has been reported as an example of truly sustainable and earth-abundant perovskite with controversial results in terms of photoluminescence and environmental stability. Our work looks at this material from a new perspective, i.e., at the nanoscale. We demonstrate the first colloidal synthesis of Cs<sub>2</sub> TiX<sub>6</sub> nanocrystals (X = Br, Cl) and observe tunable morphology and size of the nanocrystals according to the set reaction temperature. The Cs<sub>2</sub> TiBr<sub>6</sub> nanocrystals synthesized at 185<sup>◦</sup> C show a bandgap of 1.9 eV and are relatively stable up to 8 weeks in suspensions. However, they do not display notable photoluminescence. The centrosymmetric crystal structure of Cs<sub>2</sub> TiBr<sub>6</sub> suggests that this material could enable third-harmonic generation (THG) responses. Indeed, we provide a clear evidence of THG signals detected by the THG microscopy technique. As only a few THG-active halide perovskite materials are known to date and they are all lead-based, our findings promote future research on Cs<sub>2</sub> TiBr<sub>6</sub> as well as on other lead-free double perovskites, with stronger focus on currently unexplored nonlinear optical applications.</p>}},
  author       = {{Grandhi, G. Krishnamurthy and Matuhina, Anastasia and Liu, Maning and Annurakshita, Shambhavee and Ali-Löytty, Harri and Bautista, Godofredo and Vivo, Paola}},
  issn         = {{2079-4991}},
  keywords     = {{Double perovskites; Lead-free halide perovskites; Nanocrystals; Nonlinear optics; Stability; Third-harmonic generation; Titanium (Ti)}},
  language     = {{eng}},
  number       = {{6}},
  publisher    = {{MDPI AG}},
  series       = {{Nanomaterials}},
  title        = {{Lead-free cesium titanium bromide double perovskite nanocrystals}},
  url          = {{http://dx.doi.org/10.3390/nano11061458}},
  doi          = {{10.3390/nano11061458}},
  volume       = {{11}},
  year         = {{2021}},
}