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This content will become publicly available on July 9, 2019

Title: Spatial–temporal spectroscopy characterizations and electronic structure of methylammonium perovskites

Using time-resolved laser-scanning confocal microscopy and ultrafast optical pump/THz probe spectroscopy, we measure photoluminescence (PL) and THz-conductivity in perovskite micro-crystals and films. PL 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 of ~18, heavy electrons, and light holes, resulting in weakly bound excitons, consistent with the binding energies from the experiment. Here, the complementary spectroscopy and simulations reveal fundamental insights into perovskite light-matter interactions.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1]
  1. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
  2. CSIR-National Chemical Lab., Maharashtra (India)
  3. Iowa State Univ., Ames, IA (United States)
Publication Date:
Report Number(s):
IS-J-9714
Journal ID: ISSN 2159-6859; PII: S2159685918001143
Grant/Contract Number:
61771402; 61505164; 11674266; 11372248; 51575297; AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
MRS Communications
Additional Journal Information:
Journal Volume: 10; Journal Issue: 25; Journal ID: ISSN 2159-6859
Publisher:
Materials Research Society - Cambridge University Press
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ultrafast spectroscopy; perovskites; excitonic spectra; electronic structure
OSTI Identifier:
1461658