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Title: Structure-property relations in amorphous carbon for photovoltaics

Carbon is emerging as a material with great potential for photovoltaics (PV). However, the amorphous form (a-C) has not been studied in detail as a PV material, even though it holds similarities with amorphous Silicon (a-Si) that is widely employed in efficient solar cells. In this work, we correlate the structure, bonding, stoichiometry, and hydrogen content of a-C with properties linked to PV performance such as the electronic structure and optical absorption. We employ first-principles molecular dynamics and density functional theory calculations to generate and analyze a set of a-C structures with a range of densities and hydrogen concentrations. We demonstrate that optical and electronic properties of interest in PV can be widely tuned by varying the density and hydrogen content. For example, sunlight absorption in a-C films can significantly exceed that of a same thickness of a-Si for a range of densities and H contents in a-C. Our results highlight promising features of a-C as the active layer material of thin-film solar cells.
Authors:
;  [1] ;  [2] ;  [3]
  1. Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, 10129 Torino (Italy)
  2. Department of Physics, University of California, Berkeley, California 94720 (United States)
  3. Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
Publication Date:
OSTI Identifier:
22311230
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; AMORPHOUS STATE; BONDING; CARBON; CONCENTRATION RATIO; DENSITY FUNCTIONAL METHOD; ELECTRONIC STRUCTURE; HYDROGEN ADDITIONS; MOLECULAR DYNAMICS METHOD; PHOTOVOLTAIC EFFECT; SILICON; SOLAR CELLS; STOICHIOMETRY; THICKNESS; THIN FILMS