126
3 Fundamentals of the Analysis Tools
n
1D polymer
Wave vector (k)
Conduction
band (CB)
Valence band
(VB)
Unoccupied
orbital level
Occupied
orbital level
π/a
−π/a
Fig. 3.13 Relationship of energy levels and energy band
HO band
ε s (k)
0
k
π/a
s = 4
LU band
s = 3
s = 2
s = 1
Vacuum
level
Ionization
potential
Electron
affinity
LU bandwidth
HO bandwidth
Band gap
Fig. 3.14 Simplified picture of an energy band with the derived electronic properties
The top point of the HO band implies the energy of the HOCO and the bottom point
of the LU band that of the LUCO. The energy bands are often plotted in the “half
Brillouin zone”,
0 ≤ k ≤
π
a
, since they have the mirror symmetry with respect to
the plane at k = 0 due to energy degeneracies originating from the time-reversal
3 Fundamentals of the Analysis Tools
n
1D polymer
Wave vector (k)
Conduction
band (CB)
Valence band
(VB)
Unoccupied
orbital level
Occupied
orbital level
π/a
−π/a
Fig. 3.13 Relationship of energy levels and energy band
HO band
ε s (k)
0
k
π/a
s = 4
LU band
s = 3
s = 2
s = 1
Vacuum
level
Ionization
potential
Electron
affinity
LU bandwidth
HO bandwidth
Band gap
Fig. 3.14 Simplified picture of an energy band with the derived electronic properties
The top point of the HO band implies the energy of the HOCO and the bottom point
of the LU band that of the LUCO. The energy bands are often plotted in the “half
Brillouin zone”,
0 ≤ k ≤
π
a
, since they have the mirror symmetry with respect to
the plane at k = 0 due to energy degeneracies originating from the time-reversal