Hole transport in solid solutions of substituted triarylmethanes in bisphenol-A-polycarbonate

Pai, D. M.; Yanus, J. F.; Štolka, M.; Renfer, Dale S.; Limburg, W. W.

doi:10.1080/13642818308227552

Cited by 72 publications

(12 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To minimize this complication, a nearly nonpolar host polymer, polystyrene, was chosen. Similarly, charge-transporting molecules with big dipole moments tend to exhibit low mobilities, 10,11,13,[23][24][25][26][27][28]79,80 again probably because their randomly located and randomly oriented dipoles contribute to energetic disorder. 11,13,23,28 A low-polarity material such as TTA ͑dipole moment 0.9 D, Ref.…”

Section: A Choice Of Materialsmentioning

confidence: 99%

Effects of geometrical disorder on hole transport in molecularly doped polymers

Young

1995

The Journal of Chemical Physics

View full text Add to dashboard Cite

The mobility of holes is compared between two molecularly doped polymer systems. The charge-transporting material in one ͓TAPC, 1,1-bis͑di-4-tolylaminophenyl͒cyclohexane͔ is a dimeric analog of the other ͑TTA, tri-4-tolylamine͒. The charge-transport sites are essentially identical, but their packing is different because of their pairing in TAPC. The influence of packing and geometrical ͑off-diagonal͒ disorder is investigated, and current theories and notions of the effects of such disorder are tested. At equal, low site concentrations, TAPC probably has the greater degree of geometrical disorder. As expected on this basis, the mobility is a less rapidly increasing ͑or more rapidly decreasing͒ function of electric field strength in TAPC than in TTA. Contrary to predictions of the Gaussian Disorder Model ͓H. Bässler, Phys. Status Solidi B 175, 15 ͑1993͔͒, there is no concomitant effect on the magnitude of the mobility as extrapolated to zero field strength.Other predictions of the model, concerning the dependence of the mobility on field and temperature, are also not verified. The manner in which the field dependence in TTA varies with varying concentration is qualitatively consistent with the results of recent simulations ͓B. Hartenstein et al., Chem. Phys. 191, 321 ͑1995͔͒, but the specific field dependence is not. A comparison of TTA at very low concentrations with a tetrameric analog leads to a proposal on the specific influence of site clustering ͑dimeric or tetrameric͒ on transport. The low-concentration data also exhibit a drift velocity that decreases with increasing field strength, nondispersive transport at low field strengths, and dispersive transport at high field strengths. The relative importance of molecular packing in general and the implications for the interpretation of transport data on other systems are discussed.

show abstract

Section: A Choice Of Materialsmentioning

confidence: 99%

Effects of geometrical disorder on hole transport in molecularly doped polymers

Young

1995

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…[1][2][3] As amorphous materials with widely adjustable compositions and properties, they are interesting systems for investigating the effects of disorder on hopping transport. 1,3,4 It has been found that the mobility of charge carriers is dramatically affected by the presence of polar moieties in the monomeric [5][6][7][8][9][10][11] or the polymeric [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] components. To investigate the mechanism, it is advantageous to hold constant the two major components and evaluate the effect of adding a third, polar component.…”

Section: Introductionmentioning

confidence: 99%

Effect of polar additives on charge transport in a molecularly doped polymer: Survey of various additives

Young¹,

Fitzgerald²

1995

The Journal of Chemical Physics

View full text Add to dashboard Cite

We have investigated the mobility of holes in a molecularly doped polymer, polystyrene doped with tri-p-tolylamine and small amounts of polar additives. The additives come from several chemical families ͑including cyano, nitro, and sulfonyl compounds͒ and range in dipole moment from 0 to 6.6 D. The mobility is dramatically reduced and its dependence on electric field strength is greatly increased by some of them. The size of both effects depends mainly on the concentration and net dipole moment of the additive; structure-specific variations are secondary. The results are compared with two current models. A model in which the additive acts as a ''dipole trap'' predicts the wrong dependence on the concentration of the additive. Attempts to interpret the effects with the Gaussian disorder model of Bässler and co-workers ͓H. Bässler, Phys. Status Solidi B 175, 15 ͑1993͔͒ are only partially successful. Possible reasons are described.

show abstract

“…Such a log l % E p dependency is observed for many organic semiconductors [92][93][94][95][96][97][98]. For other polymers with an extraordinarily high mobility, such as m-LPPP (l&10 -3 cm 2 V -1 s -1 ) [99], which is at least one order of magnitude higher than the highest mobility observed in PPV and its derivatives [38,100,101], only a weak dependence l (E) is observed [99].…”

Section: Field-induced Injectionmentioning

confidence: 92%

Solid‐State Aspects of Conjugated Semiconductors

Graupner

Tasch

Leising

1999

Semiconducting Polymers

View full text Add to dashboard Cite

Conjugated semiconductors can exhibit energy bandgaps of 1 eV up to several eVs depending on the choice of the (1) building blocks, (2) the number of such building blocks, and (3) their precise arrangement with respect to each other. Therefore, they cover the region of narrow bandgap materials which absorb and emit light in the infrared region (a) and show reasonable charge transport properties. However, via the visible region (b), they even extend to the ultraviolet spectral range (c), performing like inorganic wide bandgap materials. This versatility and several other advantages such as mechanical flexibility, very high photoluminescence quantum yields (PL QY), easy production of large areas outweigh the intrinsic instability of conjugated molecules to photo-oxidation. Except for applications where long-term stability is not required [1], a proper encapsulation has to be used to introduce conjugated semiconductors for technical applications; such an encapsulation is for example intrinsic to applications such as capacitors and batteries [2].This chapter is organized as follows: after a brief introduction into the class of conjugated semiconductors we will discuss the solid state properties needed in order to achieve the functionalities required for efficient device operation, based on this class of materials. Very different degrees of short and long range order can be obtained in conjugated semiconductors; we will describe them and discuss their consequences on macroscopic properties of films of these materials. Since the properties of the excited states in conjugated semiconductors are both a highly relevant question of fundamental research and essential for applications we will treat the field of excited states spectroscopy in a separate section. This section will be followed by a treatise of device aspects of light emitting devices made from conjugated molecules. Before concluding we will briefly discuss the photophysics of excitation energy transfer and the properties of highly emissive conjugated systems under high excitation densities.

show abstract

Hole transport in solid solutions of substituted triarylmethanes in bisphenol-A-polycarbonate

Cited by 72 publications

References 20 publications

Effects of geometrical disorder on hole transport in molecularly doped polymers

Effects of geometrical disorder on hole transport in molecularly doped polymers

Effect of polar additives on charge transport in a molecularly doped polymer: Survey of various additives

Solid‐State Aspects of Conjugated Semiconductors

Contact Info

Product

Resources

About