Hole transport in polyfluorene-based sandwich-type devices: Quantitative analysis of the role of energetic disorder

Monte Carlo study of charge transport in organic sandwich-type single-carrier devices: Effects of Coulomb interactions

“…It was shown that the mobility obtained from that study can provide an excellent quantitative explanation of measured currentvoltage characteristics of hole-only devices of two derivatives of the semiconducting polymer poly(p-phenylenevinylene) (PPV), 8 as well as a derivative of polyfluorene. 9 It was found that in these devices at room temperature the density dependence of the hole mobility is more important than the field dependence. We will refer to this extension of the GDM, regarding the inclusion of the density dependence of the mobility, as the extended Gaussian disorder model (EGDM).…”

“…In the above device-modeling studies within the EGDM and ECDM, a one-dimensional (1D) continuum drift 8 or drift-diffusion equation 9,14 was solved using a mobility with a parametrization of the dependence on temperature, electric field, and carrier density based on a numerical solution for the mobility obtained by solving the Pauli master equation for the site-occupational probabilities. 8,10 In order to investigate the consistency of this approach and to study the injection of carriers in more detail, we recently performed a computational study of single-carrier devices by solving the Pauli master equation for a collection of sites representing a full three-dimensional (3D) device, including its electrodes.…”

Effects of disorder on the current density and recombination profile in organic light-emitting diodes

“…[10][11][12] We will refer to the parametrization of the temperature, field, and density-dependent mobility as given by Pasveer et al, 11 based on the results of a master-equation ͑ME͒ study, as the "extended Gaussian disorder model" ͑EGDM͒. Successful quantitative descriptions of hole transport in paraphenylene-vinylene and polyfluorene-based sandwich-type devices, assuming a Gaussian DOS, were given by Pasveer et al 11 and Van Mensfoort et al, 13 respectively.…”

Relation between the built-in voltage in organic light-emitting diodes and the zero-field voltage as measured by electroabsorption

“…For the devices studied, the charge-carrier density and electric field dependence of the mobility is well-known from an analysis of steady-state current density versus voltage ͓J͑V͔͒ measurements. 8 This makes it possible to accurately determine V bi from such measurements, using a drift-diffusion device model. Section II contains a description of the material and device structures, and of the experimental methods.…”

“…The built-in voltage may be determined using, for example, capacitance-voltage measurements, 5 photovoltaic measurements, 6 steady-state current-voltage measurements, 8 and electroabsorption ͑EA͒ measurements. [9][10][11][12][13][14][15][16][17][18][19][20] The latter method, which probes the electric field in OLEDs, is the subject of this paper.…”