Abstract:
n this work, alternative architecture for polymer/fullerene solar cells has been explored using
titanium dioxide nanolayers which invert the polarity of the cell and may relax the necessity to
have a hole-collecting buffer layer poly(styrene sulfonate)-doped poly(ethylene dioxy-thiophene)
(PEDOT:PSS). This work particularly focuses on the performance of the inverted devices with dense
TiO2 nanolayers as a function of temperature, illumination intensity and time. We find that both
temperature and illumination intensity slightly influence the power conversion efficiency of devices
with the PEDOT:PSS layer. However, the inverted solar cells without the PEDOT:PSS layer showed
very different characteristics regarding the power conversion efficiency which increased significantly
with the operating temperature from 30 C to 65 C. This was attributed to a consequence from the
strong and positive temperature dependence of open-circuit voltage which may be due to a “kink”
in the current–voltage characteristics near the open-circuit voltage.
