15 π-Conjugated Polymers Incorporating Naphthalene-Based …
557
15.3.5 NOT-Based Polymer
Among the hybrid naphthalene-based units, NOT was used as the acceptor unit for a
polymer in combination with the quaterthiophene donor unit (PNOT4T) (Fig. 15.10e)
(Mikie and Osaka 2018). The solubility of PNOT4T was significantly higher than that
of the parent polymers, PNTz4T and PNOz4T, likely originating from the unsymmetrical structure of NOT that would lead to a regiorandom polymer backbone.
Nevertheless, PNOT4T had high crystallinity with the edge-on orientation in the
polymer-neat film, and with the face-on orientation in the blend film, similar to the
parent polymers. The absorption range and the E g (1.56 eV) were also similar to
those of the parent systems. Interestingly, the HOMO and LUMO energy levels were
in between those of PNTz4T and PNOz4T. The OPV cells with the inverted structure fabricated using PC 71 BM as the n-type material exhibited the maximum PCE of
8.9% (J SC = 17.7 mA cm
–2 , V OC = 0.77 V, and FF = 0.65), which was reasonably
high when the electronic properties and the film structures were considered.
15.4 Summary
This section highlighted a series of naphthalene-based nitrogen-containing heteroaromatics with symmetrical and unsymmetrical structures for π-conjugated polymers
that are useful for organic electronic devices, in particular, OPVs. Due to the electron deficiency and the rigid structure, these heteroaromatics provide highly optically active π-conjugated polymers with broad absorption ranges, relatively deep
HOMO and LUMO energy levels, and highly crystalline structures, all of which are
very important for organic electronic applications. π-Conjugated polymers based on
these building units have provided very high efficiencies of over 10% in OPVs when
blended with both fullerene and non-fullerene materials.
References
Adachi C, Hattori R, Kaji H, Tsujimura T (2019) Handbook of organic light-emitting diodes.
Springer
Bao Z, Locklin J (2007) Organic field-effect transistors. CRC Press
Biniek L, Schroeder BC, Nielsen CB, McCulloch I (2012) Recent advances in high mobility donoracceptor semiconducting polymers. J Mater Chem 22:14803–14813
Boudreault P-LT, Najari A, Leclerc M (2011) Processable low-bandgap polymers for photovoltaic
applications. Chem Mater 23:456–469
Brabec C, Scherf U, Dyakonov V (2014) Organic photovoltaics. Wiley-VCH
Dong Y, Hu X, Duan C, Liu P, Liu S, Lan L, Chen D, Ying L, Su S, Gong X, Huang F, Cao Y (2013)
A series of new medium-bandgap conjugated polymers based on naphtho[1,2-c:5,6-c]bis(2-octyl[1,2,3]triazole) for high-performance polymer solar cells. Adv Mater 25:3683–3688
557
15.3.5 NOT-Based Polymer
Among the hybrid naphthalene-based units, NOT was used as the acceptor unit for a
polymer in combination with the quaterthiophene donor unit (PNOT4T) (Fig. 15.10e)
(Mikie and Osaka 2018). The solubility of PNOT4T was significantly higher than that
of the parent polymers, PNTz4T and PNOz4T, likely originating from the unsymmetrical structure of NOT that would lead to a regiorandom polymer backbone.
Nevertheless, PNOT4T had high crystallinity with the edge-on orientation in the
polymer-neat film, and with the face-on orientation in the blend film, similar to the
parent polymers. The absorption range and the E g (1.56 eV) were also similar to
those of the parent systems. Interestingly, the HOMO and LUMO energy levels were
in between those of PNTz4T and PNOz4T. The OPV cells with the inverted structure fabricated using PC 71 BM as the n-type material exhibited the maximum PCE of
8.9% (J SC = 17.7 mA cm
–2 , V OC = 0.77 V, and FF = 0.65), which was reasonably
high when the electronic properties and the film structures were considered.
15.4 Summary
This section highlighted a series of naphthalene-based nitrogen-containing heteroaromatics with symmetrical and unsymmetrical structures for π-conjugated polymers
that are useful for organic electronic devices, in particular, OPVs. Due to the electron deficiency and the rigid structure, these heteroaromatics provide highly optically active π-conjugated polymers with broad absorption ranges, relatively deep
HOMO and LUMO energy levels, and highly crystalline structures, all of which are
very important for organic electronic applications. π-Conjugated polymers based on
these building units have provided very high efficiencies of over 10% in OPVs when
blended with both fullerene and non-fullerene materials.
References
Adachi C, Hattori R, Kaji H, Tsujimura T (2019) Handbook of organic light-emitting diodes.
Springer
Bao Z, Locklin J (2007) Organic field-effect transistors. CRC Press
Biniek L, Schroeder BC, Nielsen CB, McCulloch I (2012) Recent advances in high mobility donoracceptor semiconducting polymers. J Mater Chem 22:14803–14813
Boudreault P-LT, Najari A, Leclerc M (2011) Processable low-bandgap polymers for photovoltaic
applications. Chem Mater 23:456–469
Brabec C, Scherf U, Dyakonov V (2014) Organic photovoltaics. Wiley-VCH
Dong Y, Hu X, Duan C, Liu P, Liu S, Lan L, Chen D, Ying L, Su S, Gong X, Huang F, Cao Y (2013)
A series of new medium-bandgap conjugated polymers based on naphtho[1,2-c:5,6-c]bis(2-octyl[1,2,3]triazole) for high-performance polymer solar cells. Adv Mater 25:3683–3688