404
A. Mishra
based on PTB7-Th/PC 71 BM active layer, a higher value than the control device without linker (8.47%). The aminosilane linker plays dual function to enhance the PCE,
which includes (1) passivating the ZnO surface via silane groups and decreasing
the surface WF of ZnO to 3.9 eV and (2) interaction with active layer to reduce the
interface contact resistance. Recently, Ma and co-workers used the similar strategy to
prepared air stable 3-aminopropyltrimethoxysilane (APTMS)-capped ZnO nanoparticle, which reduced the surface adsorbed oxygen defects, improved the charge transfer efficiency and most importantly suppressed the light-soaking effect of ZnO (Wei
et al. 2018). The PCE of PTB7-Th/PC 71 BM using ZnO@APTMS gave a PCE of
9.07%, much higher than the bare ZnO (4.39%). It is interesting to note that the PCE
of modified ZnO-based device does not influenced by the light soaking, however,
the ZnO-based device was almost doubled after UV light soaking. The devices with
modified interlayer also showed excellent air stability for a year.
Various polythiophene derivatives were prepared using pendant amino functionalities, such as t–butylpyridinium (P3TBPHT), trimethylammonium (P3TMAHT)
and imidazolium (P3IMDHT). The polymers were synthesized by quaternization
reaction of poly[3-(6-bromohexyl)thiophene] with the corresponding amines. The
P3TBPHT and PEDOT:PSS were deposited on the ITO surface using eLbL technique discussed above. The number of layers control the WF of ITO from 4.6 to
3.8 eV and successfully used as cathode buffer layer. The OSCs prepared using
P3TBPHT:PEDOT layer gave excellent PCEs of 5.6% and outstanding device stability retaining >90% of initial performance when stored over 1000 h in air compared
to other metal oxides (Worfolk et al. 2012). Yang and co-workers P3TMAHT:SDS
(sodium dodecylbenzene sulfonate) complex by simple mixing of both compounds
and successfully used as polyelectrolyte in P3HTP:C 61 BM BHJ achieving PCE of
4.0% almost double compared to only Al (2.12%) due to large improvement in the
V OC and FF (Chang et al. 2012). Kesters et al. used an imidazolium-substituted polythiophene P3IMDHT as ETL, which perform close to the value of other analogous
conjugated polyelectrolytes (CPE) (Kesters et al. 2013). The device performance
also depends on the molecular weight (MW) of P3IMDHT and high MW gave the
best performance. The interlayer creates an extra built-in electric field promoting
charge transfer from the BHJ layer into the interlayer as investigated by scanning
probe microscopy (Drijkoningen et al. 2014). Zilberberg et al. used an ultrathin layer
of P3IMDHT as CIL in an PCDTBT:PC 71 BM inverted device which achieved very
similar PCE (~4.8%) to that obtained for device with TiO 2 interlayer (Zilberberg
et al. 2013). P3MAHT CPE when used over ITO/AZO layer an improved device
performance was observed (Min et al. 2013).
A. Mishra
based on PTB7-Th/PC 71 BM active layer, a higher value than the control device without linker (8.47%). The aminosilane linker plays dual function to enhance the PCE,
which includes (1) passivating the ZnO surface via silane groups and decreasing
the surface WF of ZnO to 3.9 eV and (2) interaction with active layer to reduce the
interface contact resistance. Recently, Ma and co-workers used the similar strategy to
prepared air stable 3-aminopropyltrimethoxysilane (APTMS)-capped ZnO nanoparticle, which reduced the surface adsorbed oxygen defects, improved the charge transfer efficiency and most importantly suppressed the light-soaking effect of ZnO (Wei
et al. 2018). The PCE of PTB7-Th/PC 71 BM using ZnO@APTMS gave a PCE of
9.07%, much higher than the bare ZnO (4.39%). It is interesting to note that the PCE
of modified ZnO-based device does not influenced by the light soaking, however,
the ZnO-based device was almost doubled after UV light soaking. The devices with
modified interlayer also showed excellent air stability for a year.
Various polythiophene derivatives were prepared using pendant amino functionalities, such as t–butylpyridinium (P3TBPHT), trimethylammonium (P3TMAHT)
and imidazolium (P3IMDHT). The polymers were synthesized by quaternization
reaction of poly[3-(6-bromohexyl)thiophene] with the corresponding amines. The
P3TBPHT and PEDOT:PSS were deposited on the ITO surface using eLbL technique discussed above. The number of layers control the WF of ITO from 4.6 to
3.8 eV and successfully used as cathode buffer layer. The OSCs prepared using
P3TBPHT:PEDOT layer gave excellent PCEs of 5.6% and outstanding device stability retaining >90% of initial performance when stored over 1000 h in air compared
to other metal oxides (Worfolk et al. 2012). Yang and co-workers P3TMAHT:SDS
(sodium dodecylbenzene sulfonate) complex by simple mixing of both compounds
and successfully used as polyelectrolyte in P3HTP:C 61 BM BHJ achieving PCE of
4.0% almost double compared to only Al (2.12%) due to large improvement in the
V OC and FF (Chang et al. 2012). Kesters et al. used an imidazolium-substituted polythiophene P3IMDHT as ETL, which perform close to the value of other analogous
conjugated polyelectrolytes (CPE) (Kesters et al. 2013). The device performance
also depends on the molecular weight (MW) of P3IMDHT and high MW gave the
best performance. The interlayer creates an extra built-in electric field promoting
charge transfer from the BHJ layer into the interlayer as investigated by scanning
probe microscopy (Drijkoningen et al. 2014). Zilberberg et al. used an ultrathin layer
of P3IMDHT as CIL in an PCDTBT:PC 71 BM inverted device which achieved very
similar PCE (~4.8%) to that obtained for device with TiO 2 interlayer (Zilberberg
et al. 2013). P3MAHT CPE when used over ITO/AZO layer an improved device
performance was observed (Min et al. 2013).