Charge transport in lithium phthalocyanine

Abstract

Articles you may be interested inCorundumfilled resonator systems for highpressure and lowtemperature electron paramagnetic resonance studies Rev.Heating and failure of niobium tip cathodes due to a highdensity pulsed field electron emission currenta)The ac electrical properties of monoclinic lithium phthalocyanine ͑LiPc͒ and of the iodinated compound LiPcI have been investigated in the frequency and temperature regimes 20 Hzрр1 GHz and 1.5 KрTр300 K, respectively. Both compounds are semiconductors with dielectric constants ⑀ ϱ Ϸ6 ͑LiPc͒ and 20 ͑LiPcI͒. Up to room temperature tunneling of charge carriers is the dominant conduction process in both compounds, yielding intrinsic dc conductivities dc Ϸ5.3ϫ10 Ϫ4 ⍀ Ϫ1 cm Ϫ1 ͑LiPc͒ and 0.2 ⍀ Ϫ1 cm Ϫ1 ͑LiPcI͒. The frequency and temperature dependence of the complex ac conductivity suggests polarons as the dominant species of charge carriers. The higher conductivity of the iodinated compound can be attributed to an enhanced mobility of the polaronic charge carriers which is most probably due to a better overlap of the orbitals along the stacking direction of the molecules.

Polaronic behavior of MnO doped LiI-AgI-B2O3 glass

“…Below 150 K, the r 0 ðTÞ plateaus are strongly frequency-dependent, which suggests that the hopping or tunneling of localized charge carriers governs the electrical transport in the whole temperature range. 6 Similar temperature dependence of the ac electrical conductivity has been observed in many semiconductor systems, i.e., lithium phthalocyanine and its iodinated version, 7 and in many semiconductor glassy systems: bismuth-vanadate, 8 iron bismuthate, 9 vanadium germanate, 10 and silver vanadate 11 semiconductor glassy systems.…”

Polarons in boron doped iron phosphate glasses

“…Besides infrared excitation in optical conductivity [5,6], the fingerprint of polarons is usually connected with the temperature and frequency dependence of ac electrical conductivity [7][8][9][10]. The ac electrical conductivity and dielectric constant as the function of frequency and temperature of eleven boron doped iron phosphate glasses was measured recently [1], and different compositions were denoted as A1, A2, … A11.…”

Polaronic behavior of La0.8Te0.2MnO3

“…At higher temperatures 0 are strongly temperature dependent, but at low temperature the ac conductivity becomes temperature independent; 0 ðTÞ plateaus are strongly frequency-dependent, which suggests that the hopping or tunneling of localized charge carriers governs the electrical transport in the whole temperature range. 6 Like in many other amorphous materials 7-10 similar temperature dependence of the ac electrical conductivity has been observed in many semiconductor systems, i.e., lithium phthalocyanine and its iodinated version 11 and in many semiconductor glassy systems: bismuth-vanadate, 12 iron bismuthate, 13 vanadium germinate, 14 silver vanadate 15 and other semiconductor glassy systems. Figure 2(a) shows the frequency dependence of the logarithm of the real part of the ac electric conductivity, log 0 , at various temperatures and the logarithm of the real part of the dielectric constant, log " 0 , versus frequency at the same temperatures (Fig.…”