Influence of the Underlying Substrate on the Physical Vapor Deposition of Zn-Phthalocyanine on Graphene

Abstract

Graphene shows great promise not only as a highly conductive flexible and transparent electrode for fabricating novel device architectures but also as an ideal synthesis platform for studying fundamental growth mechanisms of various materials. In particular, directly depositing metal phthalocyanines (MPc’s) on graphene is viewed as a compelling approach to improve the performance of organic photovoltaics and light-emitting diodes. In this work, we systematically investigate the ZnPc physical vapor deposition (PVD) on graphene either as-grown on Cu or as-transferred on various substrates including Si(100), C-plane sapphire, SiO2/Si, and h-BN. To better understand the effect of the substrate on the ZnPc structure and morphology, we also compare the ZnPc growth on highly crystalline single- and multilayer graphene. The experiments show that, for identical deposition conditions, ZnPc exhibits various morphologies such as high-aspect-ratio nanowires or a continuous film when changing the substrate supporting graphene. ZnPc morphology is also found to transition from a thin film to a nanowire structure when increasing the number of graphene layers. Our observations suggest that substrate-induced changes in graphene affect the adsorption, surface diffusion, and arrangement of ZnPc molecules. This study provides clear guidelines to control MPc crystallinity, morphology, and molecular orientations which drastically influence the (opto)­electronic properties.

ZnPc based multifunctional devices designed as fast capacitors, rectifiers, infrared detectors and microwave resonators adequate for 6 G technology applications

“…The subscripts 1 and 2 related to Ag/n Si and Au n Si / Schottky-type interfaces, respectively. In equations (5) )), L n p , = t D n p n p , , is the characteristic length, N D and N A are the density of donors and acceptors in respective layers and n and p are the free carrier concentrations.…”

“…Literature data reported strong effect of the underlying substrates on the performance of ZnPc based devices [5]. As for examples ZnPc coated onto graphene/Cu or Si(100), C-plane sapphire and SiO 2 /Si displayed different structures and morphologies which strongly affected the optoelectronic properties of the films [5].…”

“…Literature data reported strong effect of the underlying substrates on the performance of ZnPc based devices [5]. As for examples ZnPc coated onto graphene/Cu or Si(100), C-plane sapphire and SiO 2 /Si displayed different structures and morphologies which strongly affected the optoelectronic properties of the films [5]. ZnPc deposited onto indium tin oxide substrates showed structural phase transitions that resulted in enhanced light absorption and novel photovoltaic properties [6].…”

Exploring Vacuum-Assisted Thin Films toward Supercapacitor Applications: Present Status and Future Prospects

“…The crystallinity improves with the increase in grain size. 96 studied the morphology of ZnPc films grown over different substrates such as Cu, Si, SiO 2 /Si, and carbon plane sapphire by physical vapor deposition. The SEM images (Figure 18) of ZnPc showed almost similar morphology when deposited over the bare substrate, but a clear distinction was observed when grown over a substrate using single-layer graphene as a growth template.…”

“…The substrate affects several growth mechanisms like physical adsorption, surface adsorption, and crystal arrangement of the atoms, which decides the crystallinity, morphology, atomic and molecular arrangement, etc. Mirabito et al 96 studied the morphology of ZnPc films grown over different substrates such as Cu, Si, SiO 2 /Si, and carbon plane sapphire by physical vapor deposition. The SEM images ( Figure 18 ) of ZnPc showed almost similar morphology when deposited over the bare substrate, but a clear distinction was observed when grown over a substrate using single-layer graphene as a growth template.…”