Charge carrier mobility of mixed-layer organic light-emitting diodes

Abstract

The authors report the investigation of the charge transport behaviors in mixed thin films of N , NЈ-diphenyl-N , NЈ-bis͑1-napthyl͒-1,1Ј-biphenyl-4 , 4Ј-diamine and tris͑8-hydroxyquinoline͒ aluminum. The extracted electron and hole drift mobility were found to be sensitive to the compositional fraction and interpreted by energy levels, charge mobilities of neat compounds, and microscopic networks within the mixed systems. The carrier conduction characteristics, therefore, were used to illustrate the electrical and optical properties of the organic light emitting devices with a mixed layer and present direct evidences on the role of the mixed layer in these devices.

Magnetic field modulated exciton generation in organic semiconductors: An intermolecular quantum correlated effect

“…To confirm the relation between MEL and blending ratio, Fig. 1(c [21]. The ratio of 30% agrees well with the ratio in the present experiments in which MEL reaches its maximum.…”

High Efficiency Red Phosphorescent Organic Light-Emitting Diodes with Simple Structure

“…Here, devices A and B were realized using two different hole transporting host materials having different charge carriers transport abilities, particularly the hole mobility. α-NPB has an ambipolar transporting ability with the hole mobility faster than that of m-MTDATA (S. W. Liu et al, 2007). Thus, mobilities of hole carriers in these mixed host single layer systems rather than hole injection barrier at the ITO/mixed host interface seems to be crucial in deciding the driving voltage.…”

“…The interesting and intriguing results on J-V in mixed host single layer devices may be explained on the basis of existing knowledge on carrier mobilities in organic materials. α-NPB exhibits an ambipolar transporting ability with electron and hole mobility values of 9×10 -4 and 6×10 -4 cm 2 /Vs, respectively (S. W. Liu et al, 2007), while the hole mobility value in m-MTDATA www.intechopen.com is 3×10 -5 cm 2 /Vs. Earlier, it was shown that the charge transport behaviors in mixed thin films of -NPB and Alq 3 are sensitive to (i) compositional fraction, and (ii) charge carriers mobilities of neat compounds (S. W. Liu et al, 2007).…”

“…α-NPB exhibits an ambipolar transporting ability with electron and hole mobility values of 9×10 -4 and 6×10 -4 cm 2 /Vs, respectively (S. W. Liu et al, 2007), while the hole mobility value in m-MTDATA www.intechopen.com is 3×10 -5 cm 2 /Vs. Earlier, it was shown that the charge transport behaviors in mixed thin films of -NPB and Alq 3 are sensitive to (i) compositional fraction, and (ii) charge carriers mobilities of neat compounds (S. W. Liu et al, 2007). The 1:1 mixed layer of -NPB and Alq 3 appeared to give lower charge carrier mobility of 10 -2~1 0 -3 order than neat films (S. W. Liu et al, 2007).…”

“…Earlier, it was shown that the charge transport behaviors in mixed thin films of -NPB and Alq 3 are sensitive to (i) compositional fraction, and (ii) charge carriers mobilities of neat compounds (S. W. Liu et al, 2007). The 1:1 mixed layer of -NPB and Alq 3 appeared to give lower charge carrier mobility of 10 -2~1 0 -3 order than neat films (S. W. Liu et al, 2007). As a consequence, the fast current flow in the device B despite the large hole injection barrier is attributed to the high hole mobility value and ambipolar nature of -NPB.…”