The application of oxidative chemical vapor deposited (oCVD) PEDOT to textured and non-planar photovoltaic device geometries for enhanced light trapping

Publication Type:

Journal Article

Source:

Org. Electron., Elsevier, Volume 14, Issue 9, p.2257-2268 (2013)

ISBN:

1566-1199

Keywords:

2013, 2013 and earlier, Hot embossing, Light trapping, oCVD, Organic photovoltaic, PEDOT, vapor deposition

Abstract:

In organic photovoltaics (OPVs), active layer thicknesses are limited by exciton diffusion length. Thus, non-planar surfaces and device
architectures are desired for enhancing the light absorption in OPVs. The
oxidative chemical vapor deposition (oCVD) process enables the formation
of conformal films of conducting polymers on complex surface structures.
oCVD poly(3,4 ethylenedioxythiophene) (PEDOT) is demonstrated to be
compatible with a wide range of nano- to macro-scale textured and
non-planar architectures that have been demonstrated to enhance light
absorption in photovoltaics by various mechanisms of light trapping, such
as lengthening optical pathways and taking advantage of reflective light
bouncing. Here, conformal oCVD (PEDOT) layers are demonstrated over
submicron features including submicron nanowedges and nanocones (with
70–100 nm groove depth and 100 nm pitch) and square gratings (50–350 nm
groove depth and 139–833.3 nm pitch). In contrast, solution-applied
PEDOT:PSS exhibits blanketing, thinning at the top of the features, and
welling up of material in the bottom of the features, thus failing to
conformally coat the complex surfaces. The application of oCVD PEDOT to
macro-scale 3D OPV architectures was also explored. Enhanced active layer
absorbance is shown using tetraphenyldibenzoperiflanthene (DBP) as the
absorbing layer over the PEDOT.