Poole-Frenkel mobility field dependence in molecularly doped polymers revisited

Are Transport Models Able To Predict Charge Carrier Mobilities in Organic Semiconductors?

“…The free charge carriers generated are, of course, sensitive to the film morphology, and the exciton breakup is facilitated by intermolecular electronic coupling and site energy disorder . Beyond static disorder effects in charge transport, the effect of thermal (phonon) fluctuations has been shown to be important in describing the mobility in low-mobility (μ < 10 –3 ) organic crystals and recently with semicrystalline polymer films. − In the context of charge transport in disordered low-mobility materials, it is commonly thought that transport is governed by thermally assisted hops over localized barriers (e.g., Poole-Frenkel or Mott hopping , ) and then the electron–phonon interaction is treated with a polaron model (e.g., a Holstein model). In particular, hole transport in disordered polymer films has been shown to localize as a result of disorder in π-bond lengths, and torsion disorder that led to polaron reorganization and models without such dynamic disorder fail to quantitatively predict the hole mobilities .…”

Analytic Modeling of Field Dependence of Charge Mobility and Applicability of the Concept of the Effective Transport Level to an Organic Dipole Glass

“…The essential role of energetic correlations in the genesis of the so-called Poole–Frenkel- (PF-) type field dependence of mobility is widely acknowledged for organic materials − and is specifically stressed in refs and . The following expression is commonly used where F is the electric field strength, e is the elementary charge, and a is the average intermolecular distance.…”