Separating Grain-Boundary and Bulk Recombination with Time-Resolved Photoluminescence Microscopy

Darius Kuciauskas, Dingyuan Lu, Sachit Grover, Gang Xiong, Markus Gloeckler

Research output: Contribution to journalArticlepeer-review

14 Scopus Citations


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 τB, 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 τB = 1.0-2.4 ns and SGB = (1-4) × 105 cm/s. The results imply the potential to improve solar cell voltage via GB passivation and reduced recombination center concentration in the GI.

Original languageAmerican English
Article numberArticle No. 233902
Number of pages5
JournalApplied Physics Letters
Issue number23
StatePublished - 4 Dec 2017

Bibliographical note

Publisher Copyright:
© 2017 Author(s).

NREL Publication Number

  • NREL/JA-5900-70418


  • crystal defects
  • doping
  • microscopy
  • polycrystals
  • semiconductors


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