On the Interface Dipole at the Pentacene−Fullerene Heterojunction: A Theoretical Study

Abstract

The electronic structure at organic/organic interfaces plays a key role, among others, in defining the quantum efficiency of organics-based photovoltaic cells. Here, we perform quantum-chemical and microelectrostatic calculations on molecular aggregates of various sizes and shapes to characterize the interfacial dipole moment at pentacene/C 60 heterojunctions. The results show that the interfacial dipole mostly originates in polarization effects due to the asymmetry in the multipolar expansion of the electronic density distribution between the interacting molecules, rather than in a charge transfer from donor to acceptor. The local dipole is found to fluctuate in sign and magnitude over the interface and appears as a sensitive probe of the relative arrangements of the pentacene and C 60 molecules (and of the resulting local electrical fields sensed by the molecular units).

BODIPY derivatives as n-type organic semiconductors: Isomer effect on carrier mobility

“…The development of single-crystal organic field effect transistors (SCOFETs) makes it possible to explore intrinsic properties of these materials [9][10][11]. p-Type organic semiconductors such as pentacene, rubrene and derivatives of them have been investigated widely [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. The recently improved theoretical understandings of organic semiconductors have even addressed the design rule of organics with high hole mobilities [28][29][30][31].…”

The (Non-)Local Density of States of Electronic Excitations in Organic Semiconductors

“…Even though electrostatic effects in organic semiconductors have been linked to the molecular quadrupole in a variety of theoretical and experimental studies [97,99,100,104,105,140,[144][145][146]148], the routine use of an interaction range cutoff resulted in a very different and significantly more local interpretation of electrostatic effects, as will be illustrated in the following section.…”

Noncovalent Interactions in Organic Electronic Materials

“…106 As we discussed in the Section 2.4, the locations of the fullerene molecules over the conjugated polymer backbones depend on the nature and position of the alkyl side-chains. 162 Furthermore, intermolecular interactions between polymer chains and fullerene molecules are known to play crucial roles on the electron-transfer rates, 163 exciton binding energies, 164 and processes of charge separation and charge recombination. 163 Hence, the performance of OPV devices does depend on the intermolecular arrangements and resulting energy landscapes at the interfaces between the polymer and fullerene phases.…”