Open AccessThickness-limited performance of CuInSe_2 nanocrystal photovoltaic devices
Author(s) -
Vahid A. Akhavan,
Matthew G. Panthani,
Brian W. Goodfellow,
Dariya K. Reid,
Brian A. Korgel
Publication year - 2010
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.00a411
Subject(s) - nanocrystal , materials science , optoelectronics , quantum efficiency , photovoltaic system , energy conversion efficiency , absorption (acoustics) , thin film , optics , nanotechnology , ecology , physics , composite material , biology
This paper reports our latest results using colloidal CuInSe₂ nanocrystal inks to prepare photovoltaic (PV) devices. Thus far, devices with nanocrystal layers processed under ambient conditions with no post-deposition treatment have achieved power conversion efficiencies of up to 3.1%. Device efficiency is largely limited by charge carrier trapping in the nanocrystal layer, and the highest device efficiencies are obtained with very thin layers-less than 150 nm-absorbing only a fraction of the incident light. Devices with thicker nanocrystal layers had lower power conversion efficiency, despite the increased photon absorption, because the internal quantum efficiency of the devices decreased significantly. The thin, most efficient devices exhibited internal quantum efficiencies as high as 40%, across a wide spectrum. Mott-Schottky measurements revealed that the active region thickness in the devices is approximately 50 nm.