How the Number of Layers and Relative Position Modulate the Interlayer Electron Transfer in π-Stacked 2D Materials

Abstract

Understanding the interfacial electron transfer (IET) between 2D layers is central to technological applications. We present a first-principles study of the IET between a zinc phthalocyanine film and few-layer graphene by using our recent method for the calculation of electronic coupling in periodic systems. The ultimate goal is the development of a predictive in silico approach for designing new 2D materials. We find IET to be critically dependent on the number of layers and their stacking orientation. In agreement with experiment, IET to single-layer graphene is shown to be faster than that to double-layer graphene due to interference effects between layers. We predict that additional graphene layers increase the number of IET pathways, eventually leading to a faster rate. These results shed new light on the subtle interplay between structure and IET, which may lead to more effective "bottom up" design strategies for these materials.

Charge transfer dynamics at the boron subphthalocyanine chloride/C60 interface: non-adiabatic dynamics study with Libra-X

“…A similar effect has been discussed in a number of other works. In particular, in the recent work of Biancardi et al, 20 a similar rationalization of the decrease of the CT rates in zinc phthalocyanine/graphene sheets when the number or graphene layers is increased was suggested. The decrease of the NACs in the systems with larger number of C 60 molecules also correlates with the increased average distances between the SubPc molecule and the nearby C 60 units (Table 5), which also contributes to lowering the overlaps of the donor and acceptor orbitals.…”

“…For these reasons, phthalocyanines and their derivatives have been attracting continuous interest as potential template chromophores that could be used in OPV materials. [19][20][21][22][23][24][25][26][27] Boron subphthalocyanine chloride (SubPc)/fullerene (C 60 ) heterojunctions have been recently attracting a lot of interest because of the high open-circuit voltages and power conversion efficiencies of such systems. [28][29][30][31][32][33][34] SubPc is composed of three nitrogen-fused diiminoisoindole rings that are connected around a boron atom and form a cone-shaped structure.…”

Dependence of electron transfer dynamics on the number of graphene layers in π-stacked 2D materials: insights from ab initio nonadiabatic molecular dynamics

“…The planar geometry of the ZnPc/FLG systems has been reported in the previous theoretical works, 29,52 which employed DFT with a range-separated hybrid functional, which would account for the eff ects we describe above. In the present work, the DFT+U approach is chosen for MD simulations because it delivers the best compromise between the accuracy of hybrid functionals and the computational efficiency of pure functionals (which exhibit very poor scaling in the PW-based implementations).…”

“…1). We utilize the atomistic setups previously used by Biancardi et al 29 In these simulation cells, the ZnPc molecule covers the FLG surface almost completely, which mimics the thin film geometry used in the experiment. 27,36 For both interfaces, a vacuum of 20 Å in the c direction is set to avoid artificial interactions between the interface and its periodic replica in this direction.…”

“…These observations reveal that interlayer coupling within the FLG is in a large part responsible for driving hot electrons from the donor molecule to the FLG. 29 In previous studies, approximate approaches have been implemented and used to investigate the eff ects of the FLG inter-layer coupling on the charge transfer dynamics. These inexpensive approaches evaluate the coupling between electronic states in a way that may erroneously contribute to the charge transfer dynamics.…”