Title: Dielectric Screening and Charge-Transfer in 2D Lead-Halide Perovskites for Reduced Exciton Binding Energies

Abstract

Layered lead-halide perovskites have shown tremendous success as an active material for optoelectronics. This is attributed to the electronic structure of the inorganic sublattice and large exciton binding energies due to quantum and dielectric confinement. Expanding functionalities for applications that depend on free-carrier generation requires new material design routes to decrease the binding energy. Here we use electronic structure methods with model Bethe–Salpeter equation (BSE) to examine the contributions of the dielectric screening and charge-transfer excited-states to the exciton binding energy of phenylethylammonium (PEA₂PbBr₄) and naphthlethylammonium (NEA₂PbBr₄) lead-bromide perovskites. Our model BSE calculations show that NEA introduces hole acceptor states which impose charge-transfer character on the exciton along with larger dielectric screening. This substantially decreases the exciton binding compared to PEA. This result suggests the use of organic cations with high dielectric screening and hole acceptor states as a viable strategy for reducing exciton binding energies in two-dimensional halide perovskites.

Authors:

Forde, Aaron  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-6245-8584"

Tretiak, Sergei  ^[2];

• Search DOE PAGES for author "Tretiak, Sergei"
• Search DOE PAGES for ORCID "0000-0001-5547-3647"

Neukirch, Amanda J.  ^[3]

• Search DOE PAGES for author "Neukirch, Amanda J."
• Search DOE PAGES for ORCID "0000-0002-6583-0086"

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+ Show Author Affiliations

1. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States, Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
2. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
3. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States

Publication Date:

Fri Dec 08 00:00:00 EST 2023

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)

OSTI Identifier:

2229457

Alternate Identifier(s):

OSTI ID: 2280572

Report Number(s):

LA-UR-23-29780
Journal ID: ISSN 1530-6984

Grant/Contract Number:  

89233218CNA000001

Resource Type:

Published Article

Journal Name:

Nano Letters

Additional Journal Information:

Journal Name: Nano Letters Journal Volume: 23 Journal Issue: 24; Journal ID: ISSN 1530-6984

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

77 NANOSCIENCE AND NANOTECHNOLOGY; exciton; binding energy; charge transfer; perovskite; dielectric; insulators; layers