TY - JOUR
T1 - Facile and noninvasive passivation, doping and chemical tuning of macroscopic hybrid perovskite crystals.
AU - Kirmani, Ahmad R.
AU - Mansour, Ahmed
AU - Yang, Chen
AU - Munir, Rahim
AU - El-Zohry, Ahmed
AU - Mohammed, Omar F.
AU - Amassian, Aram
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The single crystals used in this study were initially synthesized in the Functional Nanomaterials Lab (FuNL), KAUST, headed by Prof. Osman M. Bakr, whose helpful comments on the results and conclusions of this study are acknowledged. A.R.K and A.E.M contributed equally to this work.
PY - 2020/3/18
Y1 - 2020/3/18
N2 - Halide vacancies and associated metallic lead (Pb°) observed at the surface and deep inside macroscopic organolead trihalide perovskite crystals is removed through a facile and noninvasive treatment. Indeed, Br2 vapor is shown to passivate Br-vacancies and associated Pb° in the bulk of macroscopic crystals. Controlling the exposure time can markedly improve the overall stoichiometry for moderate exposures or introduce excessive bromide for long exposures, resulting in p-doping of the crystals. In the low dose passivation regime, Hall effect measurements reveal a ca. 3-fold increase in carrier mobility to ca. 15 cm2V-1s-1, while the p-doping increases the electrical conductivity ca. 10000-fold, including a 50-fold increase in carrier mobility to ca. 150 cm2V-1s-1. The ease of diffusion of Br2 vapor into macroscopic crystals is ascribed to the porosity allowed in rapidly grown crystals through aggregative processes of the colloidal sol during growth of films and macroscopic crystals. This process is believed to form significant growth defects, including open voids, which may be remnants of the escaping solvent at the solidification front. These results suggest that due to the sol-gel-like nature of the growth process, macroscopic perovskite crystals reported in this study are far from perfect and point to possible pathways to improving the optoelectronic properties of these materials. Nevertheless, the ability of the vapor-phase approach to access and tune the bulk chemistry and properties of nominally macroscopic perovskite crystals provides interesting new opportunities to precisely manipulate and functionalize the bulk properties of hybrid perovskite crystals in a noninvasive manner.
AB - Halide vacancies and associated metallic lead (Pb°) observed at the surface and deep inside macroscopic organolead trihalide perovskite crystals is removed through a facile and noninvasive treatment. Indeed, Br2 vapor is shown to passivate Br-vacancies and associated Pb° in the bulk of macroscopic crystals. Controlling the exposure time can markedly improve the overall stoichiometry for moderate exposures or introduce excessive bromide for long exposures, resulting in p-doping of the crystals. In the low dose passivation regime, Hall effect measurements reveal a ca. 3-fold increase in carrier mobility to ca. 15 cm2V-1s-1, while the p-doping increases the electrical conductivity ca. 10000-fold, including a 50-fold increase in carrier mobility to ca. 150 cm2V-1s-1. The ease of diffusion of Br2 vapor into macroscopic crystals is ascribed to the porosity allowed in rapidly grown crystals through aggregative processes of the colloidal sol during growth of films and macroscopic crystals. This process is believed to form significant growth defects, including open voids, which may be remnants of the escaping solvent at the solidification front. These results suggest that due to the sol-gel-like nature of the growth process, macroscopic perovskite crystals reported in this study are far from perfect and point to possible pathways to improving the optoelectronic properties of these materials. Nevertheless, the ability of the vapor-phase approach to access and tune the bulk chemistry and properties of nominally macroscopic perovskite crystals provides interesting new opportunities to precisely manipulate and functionalize the bulk properties of hybrid perovskite crystals in a noninvasive manner.
UR - http://hdl.handle.net/10754/662210
UR - https://dx.plos.org/10.1371/journal.pone.0230540
UR - http://www.scopus.com/inward/record.url?scp=85081910856&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0230540
DO - 10.1371/journal.pone.0230540
M3 - Article
C2 - 32182285
SN - 1932-6203
VL - 15
SP - e0230540
JO - PloS one
JF - PloS one
IS - 3
ER -