TY - JOUR
T1 - Time-Resolved Stark Spectroscopy in CdSe Nanoplatelets
T2 - Exciton Binding Energy, Polarizability, and Field-Dependent Radiative Rates
AU - Scott, Riccardo
AU - Achtstein, Alexander W.
AU - Prudnikau, Anatol V.
AU - Antanovich, Artsiom
AU - Siebbeles, Laurens D A
AU - Artemyev, Mikhail
AU - Woggon, Ulrike
PY - 2016
Y1 - 2016
N2 - We present a study of the application potential of CdSe nanoplatelets (NPLs), a model system for colloidal 2D materials, as field-controlled emitters. We demonstrate that their emission can be changed by 28% upon application of electrical fields up to 175 kV/cm, a very high modulation depth for field-controlled nanoemitters. From our experimental results we estimate the exciton binding energy in 5.5 monolayer CdSe nanoplatelets to be EB = 170 meV; hence CdSe NPLs exhibit highly robust excitons which are stable even at room temperature. This opens up the possibility to tune the emission and recombination dynamics efficiently by external fields. Our analysis further allows a quantitative discrimination of spectral changes of the emission energy and changes in PL intensity related to broadening of the emission line width as well as changes in the intrinsic radiative rates which are directly connected to the measured changes in the PL decay dynamics. With the developed field-dependent population model treating all occurring field-dependent effects in a global analysis, we are able to quantify, e.g., the ground state exciton transition dipole moment (3.0 × 10-29 Cm) and its polarizability, which determine the radiative rate, as well as the (static) exciton polarizability (8.6 × 10-8 eV cm2/kV2), all in good agreement with theory. Our results show that an efficient field control over the exciton recombination dynamics, emission line width, and emission energy in these nanoparticles is feasible and opens up application potential as field-controlled emitters.
AB - We present a study of the application potential of CdSe nanoplatelets (NPLs), a model system for colloidal 2D materials, as field-controlled emitters. We demonstrate that their emission can be changed by 28% upon application of electrical fields up to 175 kV/cm, a very high modulation depth for field-controlled nanoemitters. From our experimental results we estimate the exciton binding energy in 5.5 monolayer CdSe nanoplatelets to be EB = 170 meV; hence CdSe NPLs exhibit highly robust excitons which are stable even at room temperature. This opens up the possibility to tune the emission and recombination dynamics efficiently by external fields. Our analysis further allows a quantitative discrimination of spectral changes of the emission energy and changes in PL intensity related to broadening of the emission line width as well as changes in the intrinsic radiative rates which are directly connected to the measured changes in the PL decay dynamics. With the developed field-dependent population model treating all occurring field-dependent effects in a global analysis, we are able to quantify, e.g., the ground state exciton transition dipole moment (3.0 × 10-29 Cm) and its polarizability, which determine the radiative rate, as well as the (static) exciton polarizability (8.6 × 10-8 eV cm2/kV2), all in good agreement with theory. Our results show that an efficient field control over the exciton recombination dynamics, emission line width, and emission energy in these nanoparticles is feasible and opens up application potential as field-controlled emitters.
KW - exciton binding energy
KW - Field-dependent PL
KW - Franz-Keldysh effect
KW - nanoplatelets
KW - quantum confined Stark effect
UR - http://www.scopus.com/inward/record.url?scp=84991710683&partnerID=8YFLogxK
U2 - 10.1021/acs.nanolett.6b03244
DO - 10.1021/acs.nanolett.6b03244
M3 - Article
AN - SCOPUS:84991710683
VL - 16
SP - 6576
EP - 6583
JO - Nano Letters: a journal dedicated to nanoscience and nanotechnology
JF - Nano Letters: a journal dedicated to nanoscience and nanotechnology
SN - 1530-6984
IS - 10
ER -