Hole Relaxation Bottlenecks in CdSe/CdTe/CdSe Lateral Heterostructures Lead to Bicolor Emission.
Nano Lett
; 24(26): 7934-7940, 2024 Jul 03.
Article
in En
| MEDLINE
| ID: mdl-38885197
ABSTRACT
Concentric lateral CdSe/CdTe/CdSe heterostructures show bicolor photoluminescence from both a red charge transfer band of the CdSe/CdTe interface and a green fluorescence from CdSe. This work uses visible and near-infrared transient spectroscopy measurements to demonstrate that the deviation from Kasha's rule arises from a hole relaxation bottleneck from CdSe to CdTe. Hole transfer can take up to 1 ns, which permits radiative relaxation of excitons remaining in CdSe. Simulations indicate that the hole relaxation bottleneck arises due to the sparse density of states and poor spatial overlap of hole states at energies near the CdSe band edge. The divergent kinetics of transfer for band edge and hot holes is exploited to vary the ratio of green and red photoluminescence with excitation wavelength, providing another knob to control emission color. These findings support the use of lateral heterojunctions as a method for slowing carrier relaxation in two-dimensional materials.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Nano Lett
Year:
2024
Document type:
Article
Affiliation country:
United States
Country of publication:
United States