Tuning Hot Carrier Cooling Dynamics by Dielectric Confinement in Two-Dimensional Hybrid Perovskite Crystals
Mohammed, Omar F.
KAUST DepartmentChemical Science Program
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
Functional Nanomaterials Lab (FuNL)
KAUST Catalysis Center (KCC)
KAUST Solar Center (KSC)
Material Science and Engineering Program
Nano Energy Lab
Physical Science and Engineering (PSE) Division
Ultrafast Laser Spectroscopy and Four-dimensional Electron Imaging Research Group
Embargo End Date2020-10-15
Permanent link to this recordhttp://hdl.handle.net/10754/659506
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AbstractHot carrier (HC) cooling is a critical photophysical process that significantly influences the optoelectronic performance of hybrid perovskite-based devices. The hot carrier extraction at the device interface is very challenging because of its ultrashort lifetime. Here, ultrafast transient reflectance spectroscopy measurements and time-domain ab initio calculations show how the dielectric constant of the organic spacers can control and slow the HC cooling dynamics in single-crystal 2D Ruddlesden–Popper hybrid perovskites. We find that (EA)2PbI4 (EA = HOC2H4NH3+) that correspond to a high dielectric constant organic spacer has a longer HC cooling time compared to that of (AP)2PbI4 (AP = HOC3H6NH3+) and (PEA)2PbI4 (PEA = C6H5C2H4NH3+). The slow HC relaxation process in the former case can be ascribed to a stronger screening of the Coulomb interactions, a small nonradiative internal conversion within the conduction bands, as well as a weak electron–phonon coupling. Our findings provide a strategy to prolong the hot carrier cooling time in low-dimensional hybrid perovskite materials by using organic spacers with reduced dielectric confinement.
CitationYin, J., Maity, P., Naphade, R., Cheng, B., He, J.-H., Bakr, O. M., … Mohammed, O. F. (2019). Tuning Hot Carrier Cooling Dynamics by Dielectric Confinement in Two-Dimensional Hybrid Perovskite Crystals. ACS Nano. doi:10.1021/acsnano.9b04085
SponsorsThis work was supported by the King Abdullah University of Science and Technology (KAUST). The work at Georgia Tech was supported by the Georgia Research Alliance and the Vasser-Woolley Foundation. We acknowledge the Supercomputing Laboratory at KAUST for their computational and storage resources, as well as their gracious assistance. We also acknowledge Dr. J. Khan for the discussions.
PublisherAmerican Chemical Society (ACS)