a lesser degree of control over the properties is required. This voyage of exploration
towards the precise synthesis of conjugated phenylene-based polymers has thus had
the dual objectives of fundamental research and practical materials science. En route
we have had to meet the sometimes conflicting gauntlets thrown down by these two
aims, which has at times involved trade-offs between the theoretically desirable and
the reasonably accessible.
Keywords Bottom-up synthesis Á Cyclodehydrogenation Á Graphene Á Nanoribbon Á
Polyphenylene
Contents
1 Graphene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
2 Expanding Synthetic Chemistry to Complex Macromolecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3 Ribbon (or Ladder) Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4 Polycyclic Aromatic Hydrocarbons as Nanographenes: The Precursor Route . . . . . . . . . . . . 70
5 Dendritic (3D) Polyphenylenes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6 Graphene Nanoribbons: The “Solution” Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
7 Graphene Nanoribbons: The Surface-Bound Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
8 From Precision Polymer Synthesis to “Cook-and-Bake” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
9 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
1 Graphene
Graphene, the monolayer subunit of the graphite lattice, has recently attracted
great attention in fundamental and applied research. Only the future will tell
whether the current excitement is just “hype” or whether there are real hopes for
new, significantly improved applications; but, the physical properties of graphene
are truly remarkable. What stands out is its unique band structure with a Brioullin
zone and very high charge carrier mobility. While this would suggest high-tech
applications in electronic devices, graphene and materials derived thereof are also
expected to play a key role in energy technologies such as batteries, supercapacitors, and catalysts for fuel cells [1, 2] (see Sect. 8).
What has almost generated as much excitement, especially among non-scientists,
is how this wonder-material was first produced. Andre Geim and Konstantin
Novoselov [3–5] simply peeled graphene sheets off bulk graphite using cellophane
tape! Their breakthrough idea, which has earned them a Nobel Prize, was to deposit
this layer on suitable substrates for further physical characterization. This exfoliation technique, although it has produced samples enabling outstanding physical
studies, cannot be the basis for robust technologies and, indeed, other preparation
methods such as chemical vapor deposition (CVD) have been applied, particularly
in attempts at fabricating transparent window electrodes [6–8]. One process
62
K. Mu ¨llen
towards the precise synthesis of conjugated phenylene-based polymers has thus had
the dual objectives of fundamental research and practical materials science. En route
we have had to meet the sometimes conflicting gauntlets thrown down by these two
aims, which has at times involved trade-offs between the theoretically desirable and
the reasonably accessible.
Keywords Bottom-up synthesis Á Cyclodehydrogenation Á Graphene Á Nanoribbon Á
Polyphenylene
Contents
1 Graphene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
2 Expanding Synthetic Chemistry to Complex Macromolecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3 Ribbon (or Ladder) Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4 Polycyclic Aromatic Hydrocarbons as Nanographenes: The Precursor Route . . . . . . . . . . . . 70
5 Dendritic (3D) Polyphenylenes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6 Graphene Nanoribbons: The “Solution” Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
7 Graphene Nanoribbons: The Surface-Bound Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
8 From Precision Polymer Synthesis to “Cook-and-Bake” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
9 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
1 Graphene
Graphene, the monolayer subunit of the graphite lattice, has recently attracted
great attention in fundamental and applied research. Only the future will tell
whether the current excitement is just “hype” or whether there are real hopes for
new, significantly improved applications; but, the physical properties of graphene
are truly remarkable. What stands out is its unique band structure with a Brioullin
zone and very high charge carrier mobility. While this would suggest high-tech
applications in electronic devices, graphene and materials derived thereof are also
expected to play a key role in energy technologies such as batteries, supercapacitors, and catalysts for fuel cells [1, 2] (see Sect. 8).
What has almost generated as much excitement, especially among non-scientists,
is how this wonder-material was first produced. Andre Geim and Konstantin
Novoselov [3–5] simply peeled graphene sheets off bulk graphite using cellophane
tape! Their breakthrough idea, which has earned them a Nobel Prize, was to deposit
this layer on suitable substrates for further physical characterization. This exfoliation technique, although it has produced samples enabling outstanding physical
studies, cannot be the basis for robust technologies and, indeed, other preparation
methods such as chemical vapor deposition (CVD) have been applied, particularly
in attempts at fabricating transparent window electrodes [6–8]. One process
62
K. Mu ¨llen