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This content will become publicly available on January 15, 2019

Title: Obtaining Large Columnar CdTe Grains and Long Lifetime on Nanocrystalline CdSe, MgZnO, or CdS Layers

CdTe solar cells have reached efficiencies comparable to multicrystalline silicon and produce electricity at costs competitive with traditional energy sources. Recent efficiency gains have come partly from shifting from the traditional CdS window layer to new materials such as CdSe and MgZnO, yet substantial headroom still exists to improve performance. Thin film technologies including Cu(In,Ga)Se2, perovskites, Cu2ZnSn(S,Se)4, and CdTe inherently have many grain boundaries that can form recombination centers and impede carrier transport; however, grain boundary engineering has been difficult and not practical. In this work, it is demonstrated that wide columnar grains reaching through the entire CdTe layer can be achieved by aggressive postdeposition CdTe recrystallization. This reduces the grain structure constraints imposed by nucleation on nanocrystalline window layers and enables diverse window layers to be selected for other properties critical for electro-optical applications. Computational simulations indicate that increasing grain size from 1 to 7 um can be equivalent to decreasing grain-boundary recombination velocity by three orders of magnitude. Here, large high-quality grains enable CdTe lifetimes exceeding 50 ns.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ;  [3] ;  [1] ;  [2] ;  [2]
  1. Univ. of Illinois, Chicago, IL (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. Colorado State Univ., Fort Collins, CO (United States)
Publication Date:
Report Number(s):
NREL/JA-5K00-68612
Journal ID: ISSN 1614-6832
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Advanced Energy Materials
Additional Journal Information:
Journal Volume: 8; Journal Issue: 11; Journal ID: ISSN 1614-6832
Publisher:
Wiley
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; 36 MATERIALS SCIENCE; CdTe; grain boundaries; recombination; solar energy; thin films
OSTI Identifier:
1456866
Alternate Identifier(s):
OSTI ID: 1416995