474
18 Organic Semiconductors
Fig. 18.1 Various organic
compounds: 1: naphtalene,
2: anthracene, 3: tetracene,
4: pentacene, 5: pyrene, 6:
perylene, 7: chrysene, 8:
pyranthrene, 9:
isoviolanthrene, 10:
anthanthrene, 11:
coronene, 12: ovalene, 13:
violanthrene, 14:
p-terphenyl, 15: rubrene,
16: m-dinaphthanthrene,
17: anthanthrone, 18:
m-dinaphthanthrone, 19:
violanthrone, 20:
pyranthrone, 21:
isoviolanthrone
(a)
(b)
(c)
(d)
(e)
Al
N
O
N
O
N
O
(f)
Fig. 18.2 Organic compounds: a thiophene, b pyridine, c poly-(p-phenyl), d poly-(p-phenylvinyl), e Alq 3 (tris-(8hydroxyquinolate)-aluminum) and f a three-dimensional view of the Alq 3 molecule. Part (f) reprinted with permission
from [1556], ©1998 AIP
18.2.2 Organic Semiconductor Crystals
Small organic molecules can crystallize into solids, so-called organic molecular crystals (OMC), due
to van-der-Waals interaction. In Fig. 18.4a, the monoclinic unit cell of an anthracene crystal [1558]
is shown as an example. Also tetracene and pentacene (Fig. 18.4b) have this layered ’herringbone‘
structure. A comparison of the unit cells of oligoacene crystals is given in Table 18.1.
Crystal growth of single crystal OMC is achieved with a variety of methods, among them sublimation, Bridgman- and Czochralski-type methods [1560, 1561], vapor phase growth [1562, 1563]
18 Organic Semiconductors
Fig. 18.1 Various organic
compounds: 1: naphtalene,
2: anthracene, 3: tetracene,
4: pentacene, 5: pyrene, 6:
perylene, 7: chrysene, 8:
pyranthrene, 9:
isoviolanthrene, 10:
anthanthrene, 11:
coronene, 12: ovalene, 13:
violanthrene, 14:
p-terphenyl, 15: rubrene,
16: m-dinaphthanthrene,
17: anthanthrone, 18:
m-dinaphthanthrone, 19:
violanthrone, 20:
pyranthrone, 21:
isoviolanthrone
(a)
(b)
(c)
(d)
(e)
Al
N
O
N
O
N
O
(f)
Fig. 18.2 Organic compounds: a thiophene, b pyridine, c poly-(p-phenyl), d poly-(p-phenylvinyl), e Alq 3 (tris-(8hydroxyquinolate)-aluminum) and f a three-dimensional view of the Alq 3 molecule. Part (f) reprinted with permission
from [1556], ©1998 AIP
18.2.2 Organic Semiconductor Crystals
Small organic molecules can crystallize into solids, so-called organic molecular crystals (OMC), due
to van-der-Waals interaction. In Fig. 18.4a, the monoclinic unit cell of an anthracene crystal [1558]
is shown as an example. Also tetracene and pentacene (Fig. 18.4b) have this layered ’herringbone‘
structure. A comparison of the unit cells of oligoacene crystals is given in Table 18.1.
Crystal growth of single crystal OMC is achieved with a variety of methods, among them sublimation, Bridgman- and Czochralski-type methods [1560, 1561], vapor phase growth [1562, 1563]