Bulk and interface properties of molybdenum trioxide-doped hole transporting layer in organic light-emitting diodes

Simplified phosphorescent organic light-emitting diodes with a WO3-doped wide bandgap organic charge transport layer

“…An increased absorption in doped CBP at long wavelengths beyond 750 nm was observed as compared to undoped CBP. Similar features have been seen in other metal oxide-doped organic materials and are often regarded as an indicator of the formation of charge transfer complexes [5,7,10]. The enhanced conductivity in CBP is clearly seen in Fig.…”

“…Electrical doping has been developed to enhance the charge transport capability of organic materials, and led to high-efficiency OLEDs based on a simple p-i-n structure [1]. Introducing organic or inorganic dopants in organic charge transport layers can dramatically increase the free carrier density by several orders of magnitude and thus improve their electrical conductivity, giving rise to a reduced operation voltage of OLEDs [2][3][4][5][6][7][8][9][10][11][12][13]. Doping can also remarkably reduce the interfacial energy barriers between the electrodes and charge transport layers [1], and therefore eliminate the need for additional charge injection layers.…”

“…They are thus well suited for p-type doping in organic materials with a deep HOMO level. Successful p-type doping of CBP, N, N 0 -bis(Inaphthyl)-N,N 0 -diphenyl-1,1 0 -biphenyl-4,4 0 -diamine (NPB), and Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) with MoO 3 has been realized [3][4][5][6][7][8][9]. The doping effect has been attributed to the formation of charge transfer (CT) complexes through electrons transferring from organic host molecules to the inorganic dopants.…”

Organic light-emitting diodes using 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane as p-type dopant

“…Regarding molecules served as the p-dopant in organic semiconductors, several strong electron acceptors or oxidants had been used, such as 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane ͑F4-TCNQ͒, 6 SbCl 5 , 15 I 2 , 16 WO 3 , 17 ReO 3 , 18 and MoO x . [19][20][21] Despite the intensively explored p-type electrical doping system, problematic issues still remain. The problems related to inorganic materials include noncompatible high deposition temperature, pixel crosstalk, low optical transparency, or material toxicity.…”

Tungsten oxide doped N,N′-di(naphthalen-1-yl)-N,N′-diphenyl-benzidine as hole injection layer for high performance organic light-emitting diodes

“…[2][3][4][5][6] Furthermore, the utilization of p doped HTL on anode electrode is also a key technique to enhance hole injection and interface stability, thus obtaining good device performance. [7][8][9][10] Recently, transition metal oxides such as WO 3 , V 2 O 5 , and MoO 3 have been frequently used as HIL in OLEDs due to the significant enhancement in device efficiency and stability. [11][12][13][14][15][16][17][18][19][20] As dopant in HTL, the efficiency of fabricated OLEDs also obtains significant improvement.…”