TY - JOUR
T1 - Role of electron injection in polyfluorene-based light emitting diodes containing PEDOT:PSS
AU - Brewer, Paul J.
AU - Lane, Paul A.
AU - Huang, Jingsong
AU - DeMello, Andrew J.
AU - Bradley, Donal D.C.
AU - DeMello, John C.
N1 - Generated from Scopus record by KAUST IRTS on 2019-11-27
PY - 2005/12/1
Y1 - 2005/12/1
N2 - We report electromodulation (EM) studies of polyfluorene-based light-emitting diodes containing poly(3,4-ethylene-dioxythiophene)-poly(styrene- sulfonate) (PEDOT:PSS), in which the barrier to hole injection is large (∼0.7 eV). Measurements are reported on devices fabricated with aluminium and barium cathodes to provide respectively poor and efficient electron injection into the active layer. The Al devices exhibit low currents, indicating low rates of electron and hole injection, whereas the Ba devices exhibit high currents and high electroluminescence efficiencies, implying efficient injection of both electrons and holes despite the large hole injection barrier. The Al devices show conventional field-induced EM behavior consistent with the Stark effect (SE). The Ba devices show conventional SE behavior for low applied biases but, above turn-on, the (field-induced) SE features vanish, indicating suppression of the internal field, and are replaced by charge-induced bleaching and absorption features. The behavior of the devices is attributed to the presence of electron traps close to the PEDOT:PSS/organic interface. The experimental findings are consistent with earlier findings by Murata, Van Woudenbergh, Poplavskyy, and Lane © 2005 The American Physical Society.
AB - We report electromodulation (EM) studies of polyfluorene-based light-emitting diodes containing poly(3,4-ethylene-dioxythiophene)-poly(styrene- sulfonate) (PEDOT:PSS), in which the barrier to hole injection is large (∼0.7 eV). Measurements are reported on devices fabricated with aluminium and barium cathodes to provide respectively poor and efficient electron injection into the active layer. The Al devices exhibit low currents, indicating low rates of electron and hole injection, whereas the Ba devices exhibit high currents and high electroluminescence efficiencies, implying efficient injection of both electrons and holes despite the large hole injection barrier. The Al devices show conventional field-induced EM behavior consistent with the Stark effect (SE). The Ba devices show conventional SE behavior for low applied biases but, above turn-on, the (field-induced) SE features vanish, indicating suppression of the internal field, and are replaced by charge-induced bleaching and absorption features. The behavior of the devices is attributed to the presence of electron traps close to the PEDOT:PSS/organic interface. The experimental findings are consistent with earlier findings by Murata, Van Woudenbergh, Poplavskyy, and Lane © 2005 The American Physical Society.
UR - https://link.aps.org/doi/10.1103/PhysRevB.71.205209
UR - http://www.scopus.com/inward/record.url?scp=33344460072&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.71.205209
DO - 10.1103/PhysRevB.71.205209
M3 - Article
SN - 1098-0121
VL - 71
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 20
ER -