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This content will become publicly available on December 4, 2018

Title: Separating grain-boundary and bulk recombination with time-resolved photoluminescence microscopy

Two-photon excitation (2PE) microscopy allows contactless and non-destructive cross-sectional analysis of grain-boundary (GB) and grain-interior (GI) properties in polycrystalline solar cells, with measurements of doping uniformity, space-charge field distribution, and carrier dynamics in different regions of the device. Using 2PE time-resolved microscopy, we analyzed charge-carrier lifetimes near the GBs and in the GI of polycrystalline thin-film CdTe solar cells doped with As. When the grain radius is larger than the minority-carrier diffusion length, GI lifetimes are interpreted as the bulk lifetimes ..tau..B, and GB recombination velocity SGB is extracted by comparing recombination rates in the GI and near GBs. In As-doped CdTe solar cells, we find ..tau..B = 1.0-2.4 ns and S GB = (1-4) x 10 5 cm/s. The results imply the potential to improve solar cell voltage via GB passivation and reduced recombination center concentration in the GI.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ;  [2] ;  [2]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. First Solar, Santa Clara, CA (United States)
Publication Date:
Report Number(s):
NREL/JA-5900-70418
Journal ID: ISSN 0003-6951; TRN: US1800417
Grant/Contract Number:
AC36-08GO28308; AC36-08-GO28308
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 111; Journal Issue: 23; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; microscopy; crystal defects; semiconductors; doping; polycrystals
OSTI Identifier:
1413180
Alternate Identifier(s):
OSTI ID: 1411285