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Title: Dynamics of Charge Transfer and Multiple Exciton Generation in the Doped Silicon Quantum Dot–Carbon Nanotube System: Density Functional Theory-Based Computation

Abstract

In this study, we use the Boltzmann transport equation (BE) to study time evolution of a photoexcited state, including phonon-mediated exciton relaxation, multiple exciton generation (MEG), and energy-transfer processes. BE collision integrals are derived using Kadanoff–Baym–Keldysh many-body perturbation theory (MBPT) based on density functional theory (DFT) simulations, including exciton effects. We apply the method to a nanostructured p–n junction composed of a 1 nm hydrogen-terminated Si quantum dot (QD) doped with two phosphorus atoms (Si 36P 2H 42) adjacent to the (6, 2) single-wall carbon nanotube (CNT) with two chlorine atoms per two unit cells adsorbed to the surface. We find that an initial excitation localized on either the QD or CNT evolves into a transient charge-transfer (CT) state where either electron or hole transfer has taken place. The CT state lifetime is about 40 fs. Also, we study MEG in this system by computing internal quantum efficiency (QE), which is the number of excitons generated from an absorbed photon during relaxation. We predict efficient MEG starting at 3E g ≃ 1.5 eV and with QE reaching QE = 1.65 at about 5E g, where E g ≃ 0.5 eV is the lowest exciton energy, i.e., the gap. However, wemore » find that including energy transfer and MEG effects suppresses CT state generation.« less

Authors:
ORCiD logo [1];  [1]; ORCiD logo [1]
  1. North Dakota State Univ., Fargo, ND (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of California, Oakland, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1543671
Grant/Contract Number:  
AC02-05CH11231; SC00001717
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 9; Journal Issue: 19; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE

Citation Formats

Kryjevski, Andrei, Mihaylov, Deyan, and Kilin, Dmitri. Dynamics of Charge Transfer and Multiple Exciton Generation in the Doped Silicon Quantum Dot–Carbon Nanotube System: Density Functional Theory-Based Computation. United States: N. p., 2018. Web. doi:10.1021/acs.jpclett.8b02288.
Kryjevski, Andrei, Mihaylov, Deyan, & Kilin, Dmitri. Dynamics of Charge Transfer and Multiple Exciton Generation in the Doped Silicon Quantum Dot–Carbon Nanotube System: Density Functional Theory-Based Computation. United States. https://doi.org/10.1021/acs.jpclett.8b02288
Kryjevski, Andrei, Mihaylov, Deyan, and Kilin, Dmitri. Mon . "Dynamics of Charge Transfer and Multiple Exciton Generation in the Doped Silicon Quantum Dot–Carbon Nanotube System: Density Functional Theory-Based Computation". United States. https://doi.org/10.1021/acs.jpclett.8b02288. https://www.osti.gov/servlets/purl/1543671.
@article{osti_1543671,
title = {Dynamics of Charge Transfer and Multiple Exciton Generation in the Doped Silicon Quantum Dot–Carbon Nanotube System: Density Functional Theory-Based Computation},
author = {Kryjevski, Andrei and Mihaylov, Deyan and Kilin, Dmitri},
abstractNote = {In this study, we use the Boltzmann transport equation (BE) to study time evolution of a photoexcited state, including phonon-mediated exciton relaxation, multiple exciton generation (MEG), and energy-transfer processes. BE collision integrals are derived using Kadanoff–Baym–Keldysh many-body perturbation theory (MBPT) based on density functional theory (DFT) simulations, including exciton effects. We apply the method to a nanostructured p–n junction composed of a 1 nm hydrogen-terminated Si quantum dot (QD) doped with two phosphorus atoms (Si36P2H42) adjacent to the (6, 2) single-wall carbon nanotube (CNT) with two chlorine atoms per two unit cells adsorbed to the surface. We find that an initial excitation localized on either the QD or CNT evolves into a transient charge-transfer (CT) state where either electron or hole transfer has taken place. The CT state lifetime is about 40 fs. Also, we study MEG in this system by computing internal quantum efficiency (QE), which is the number of excitons generated from an absorbed photon during relaxation. We predict efficient MEG starting at 3Eg ≃ 1.5 eV and with QE reaching QE = 1.65 at about 5Eg, where Eg ≃ 0.5 eV is the lowest exciton energy, i.e., the gap. However, we find that including energy transfer and MEG effects suppresses CT state generation.},
doi = {10.1021/acs.jpclett.8b02288},
url = {https://www.osti.gov/biblio/1543671}, journal = {Journal of Physical Chemistry Letters},
issn = {1948-7185},
number = 19,
volume = 9,
place = {United States},
year = {2018},
month = {9}
}

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