Experimental Studies of Plasmonic Nanoparticle Effects on Organic Solar Cells - Organic Solar Cells: Materials and Device Physics - page 235

Fig. 8.23 Representative
cross-section SEM image of
the film structure
PEDOT:PSS ? Au NPs/
P3HT:PCBM ? Au NPs [ 35 ]
8.4.5 Section Summary
In conclusion, by incorporating Au NPs into all organic layers in the OSCs, the
efficiency can be improved by 22 %. The improvement is attributed to the accu-
mulated enhancements in device performance due to addition of NPs into indi-
vidual layers. NPs doped into PEDOT:PSS mainly contributes to more efficient
hole collection due to increased PEDOT:PSS/P3HT:PCBM interfacial area, while
NPs doped into the active layer improves optical absorption by LSPR effects and
improves the hole mobility of the active layer. No optical coupling was observed
between NPs in PEDOT:PSS and P3HT:PCBM. As the effects of NPs in PE-
DOT:PSS or P3HT:PCBM are separated, the PCE improvement was attributed to
the accumulated benefits of NPs in the individual organic layers. Although the NPs
in different layer did not interact to achieve extra improvements in PCE, this study
shows that the advantages of incorporating NPs in individual layers can be utilized
together to achieve larger increases of OSC performance and the role of NPs play
when incorporated into OSCs has been further clarified, which is highly useful in
designing high efficiency OSCs in the future.
8.5 Conclusions
We have discussed in detail that the effect of incorporation of NPs into various
layers of an OSC. In Sect. 8.2 , it has been reported [ 36 ] that about 13 %
improvement in PCE for PSCs incorporating PEG-capped Au NPs in PEDOT:PSS,
with enhancements mainly originating from J sc and FF. A peak in PCE perfor-
mance is obtained at an Au NP concentration of 0.32 wt% [ 35 ]. The contribution
of LSPR effect to performance improvement has been theoretically and experi-
mentally described. Both theoretical and experimental results show that absorption