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Luminescent Intermediates and Humidity-Dependent Room-Temperature Conversion of the MAPbI3 Perovskite Precursor

Li, Jun LU ; Dobrovolsky, Alexander LU ; Merdasa, Aboma LU ; Unger, Eva L. LU and Scheblykin, Ivan G. LU (2018) In ACS Omega 3(10). p.14494-14502
Abstract

Preparation of metal-halide perovskites under room temperature attracts attention because of energy saving by removing thermal annealing. Room-temperature transformation of spin-cast wet films consisting of methylammonium (MA) iodide, PbI2, and dimethylformamide toward solid MAPbI3 perovskite proceeds via several intermediate crystalline states and is strongly dependent on ambient humidity. Light transmission and photoluminescence (PL) microscopy and spectroscopy were used to monitor the growth of crystals and transformation of their properties in time under nitrogen atmosphere at room temperature. Under low humidity, a highly luminescent intermediate phase with low absorption in the visible range appears, with the... (More)

Preparation of metal-halide perovskites under room temperature attracts attention because of energy saving by removing thermal annealing. Room-temperature transformation of spin-cast wet films consisting of methylammonium (MA) iodide, PbI2, and dimethylformamide toward solid MAPbI3 perovskite proceeds via several intermediate crystalline states and is strongly dependent on ambient humidity. Light transmission and photoluminescence (PL) microscopy and spectroscopy were used to monitor the growth of crystals and transformation of their properties in time under nitrogen atmosphere at room temperature. Under low humidity, a highly luminescent intermediate phase with low absorption in the visible range appears, with the PL spectra composed of several bands in the range from 600 to 760 nm. We assign these bands to low-dimensional (nanocrystals and two-dimensional inclusions) MAPbI3 intermediates, where the exciton confinement shifts the spectrum to higher energies in comparison with the bulk MAPbI3. The intermediate levels of ambient humidity (10-50%) appear to catalyze the conversion of the intermediate phase to MAPbI3. At a high ambient humidity (>80%), the initially formed MAPbI3 is quickly transformed to the transparent hydrate phase of MAPbI3. The role of ambient water catalyzing the material transformation by competing for Pb coordination with the solvent molecules is discussed.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
ACS Omega
volume
3
issue
10
pages
9 pages
publisher
American Chemical Society (ACS)
external identifiers
  • scopus:85056260898
ISSN
2470-1343
DOI
10.1021/acsomega.8b01799
language
English
LU publication?
yes
id
5665fe8a-2092-43f0-88c2-1ac29a7aabd0
date added to LUP
2018-11-22 13:19:48
date last changed
2019-02-20 11:37:15
@article{5665fe8a-2092-43f0-88c2-1ac29a7aabd0,
  abstract     = {<p>Preparation of metal-halide perovskites under room temperature attracts attention because of energy saving by removing thermal annealing. Room-temperature transformation of spin-cast wet films consisting of methylammonium (MA) iodide, PbI<sub>2</sub>, and dimethylformamide toward solid MAPbI<sub>3</sub> perovskite proceeds via several intermediate crystalline states and is strongly dependent on ambient humidity. Light transmission and photoluminescence (PL) microscopy and spectroscopy were used to monitor the growth of crystals and transformation of their properties in time under nitrogen atmosphere at room temperature. Under low humidity, a highly luminescent intermediate phase with low absorption in the visible range appears, with the PL spectra composed of several bands in the range from 600 to 760 nm. We assign these bands to low-dimensional (nanocrystals and two-dimensional inclusions) MAPbI<sub>3</sub> intermediates, where the exciton confinement shifts the spectrum to higher energies in comparison with the bulk MAPbI<sub>3</sub>. The intermediate levels of ambient humidity (10-50%) appear to catalyze the conversion of the intermediate phase to MAPbI<sub>3</sub>. At a high ambient humidity (&gt;80%), the initially formed MAPbI<sub>3</sub> is quickly transformed to the transparent hydrate phase of MAPbI<sub>3</sub>. The role of ambient water catalyzing the material transformation by competing for Pb coordination with the solvent molecules is discussed.</p>},
  author       = {Li, Jun and Dobrovolsky, Alexander and Merdasa, Aboma and Unger, Eva L. and Scheblykin, Ivan G.},
  issn         = {2470-1343},
  language     = {eng},
  month        = {10},
  number       = {10},
  pages        = {14494--14502},
  publisher    = {American Chemical Society (ACS)},
  series       = {ACS Omega},
  title        = {Luminescent Intermediates and Humidity-Dependent Room-Temperature Conversion of the MAPbI<sub>3</sub> Perovskite Precursor},
  url          = {http://dx.doi.org/10.1021/acsomega.8b01799},
  volume       = {3},
  year         = {2018},
}