Title

Spatial–temporal spectroscopy characterizations and electronic structure of methylammonium perovskites

Publication Date

7-9-2018

Department

Ames Laboratory; Chemistry; Electrical and Computer Engineering; Physics and Astronomy; Microelectronics Research Center (MRC)

Campus Units

Chemistry, Electrical and Computer Engineering, Physics and Astronomy, Ames Laboratory, Microelectronics Research Center (MRC)

OSTI ID+

1461658

Report Number

IS-J 9714

DOI

10.1557/mrc.2018.114

Journal Title

MRS Communications

Volume Number

8

Issue Number

3

First Page

961

Last Page

969

Abstract

Using time-resolved laser-scanning confocal microscopy and ultrafast optical pump/THz probe spectroscopy, we measure photoluminescence and THz-conductivity in perovskite micro-crystals and films. Photoluminescence quenching and lifetime variations occur from local heterogeneity. Ultrafast THz-spectra measure sharp quantum transitions from excitonic Rydberg states, providing weakly bound excitons with a binding energy of ~13.5 meV at low temperatures. Ab-initio electronic structure calculations give a direct band gap of 1.64 eV, a dielectric constant ~18, heavy electrons, and light holes, resulting in weakly bound excitons, consistent with the binding energies from experiment. The complementary spectroscopy and simulations reveal fundamental insights into perovskite light-matter interactions.

DOE Contract Number(s)

61771402; 61505164; 11674266; 11372248; 51575297; AC02-07CH11358

Language

en

Department of Energy Subject Categories

36 MATERIALS SCIENCE

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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