15 research outputs found
'Damage control orthopaedics' in patients with delayed referral to a tertiary care center: experience from a place where Composite Trauma Centers do not exist
Charge-carrier mobilities in binary mixtures of discotic triphenylene derivatives as a function of temperature
Quantitative Tomography of Organic Photovoltaic Blends at the Nanoscale
The
success of semiconducting organic materials has enabled green technologies
for electronics, lighting, and photovoltaics. However, when blended
together, these materials have also raised novel fundamental questions
with respect to electronic, optical, and thermodynamic properties.
This is particularly important for organic photovoltaic cells based
on the bulk heterojunction. Here, the distribution of nanoscale domains
plays a crucial role depending on the specific device structure. Hence,
correlation of the aforementioned properties requires 3D nanoscale
imaging of materials domains, which are embedded in a multilayer device.
Such visualization has so far been elusive due to lack of contrast,
insufficient signal, or resolution limits. In this Letter, we introduce
spectral scanning transmission electron tomography for reconstruction
of entire volume plasmon spectra from rod-shaped specimens. We provide
3D structural correlations and compositional mapping at a resolution
of approximately 7 nm within advanced organic photovoltaic tandem
cells. Novel insights that are obtained from quantitative 3D analyses
reveal that efficiency loss upon thermal annealing can be attributed
to subtle, fundamental blend properties. These results are invaluable
in guiding the design and optimization of future devices in plastic
electronics applications and provide an empirical basis for modeling
and simulation of organic solar cells