Charge-transfer dynamics and nonlocal dielectric permittivity tuned with metamaterial structures as solvent analogues

Abstract

Charge transfer (CT) is a fundamental and ubiquitous mechanism in biology, physics and chemistry. Here, we evidence that CT dynamics can be altered by multi-layered hyperbolic metamaterial (HMM) substrates. Taking triphenylene:perylene diimide dyad supramolecular self-assemblies as a model system, we reveal longer-lived CT states in the presence of HMM structures, with both charge separation and recombination characteristic times increased by factors of 2.4 and 1.7-that is, relative variations of 140 and 73%, respectively. To rationalize these experimental results in terms of driving force, we successfully introduce image dipole interactions in Marcus theory. The non-local effect herein demonstrated is directly linked to the number of metal-dielectric pairs, can be formalized in the dielectric permittivity, and is presented as a solid analogue to local solvent polarity effects. This model and extra PH3T:PC60BM results show the generality of this non-local phenomenon and that a wide range of kinetic tailoring opportunities can arise from substrate engineering. This work paves the way toward the design of artificial substrates to control CT dynamics of interest for applications in optoelectronics and chemistry.

Ultrafast direct electron transfer at organic semiconductor and metal interfaces

“…Lastly, the overall efficiency of charge transfer of this complex interface is not as high as that observed in other nanomaterials ( 7 , 15 ). Yet, it could be enhanced by optical engineering, for example, using mesoscopic framework ( 66 ) to prepare interfaces with a larger surface area or using hyperbolic metamaterials ( 67 ) to enhance charge transfer rate.…”

Building an Organic Solar Cell: Fundamental Procedures for Device Fabrication

“…AFM 3D images for PEDOT:PSS films had revealed areas of smaller and larger heights which are represented in the image by light and dark areas respectively. These bright and dark areas are commonly associated with PEDOT and PSS rich regions [25,26]. The low RMS value for the pristine PEDOT:PSS film of 1.124 nm implied its smooth surface (Figure 9).…”

Study of the effect of excited state concentration on photodegradation of the p3ht polymer

“…Recently, the reduction of both charge separation and charge recombination rates in the triphenylene: perylene diimide dyad {TriPh(donor): PerDi(acceptor)} has been observed in vicinity of metallic surfaces and lamellar metal-dielectric metamaterials 31 . The qualitatively similar effect (reduction of the recombination rate) has been reported in the p3ht:PC 60 BM polymer blend 31 . These two experiments show the generality of our recent finding 17 (reduction of the rate of a chemical reaction in vicinity of metal).…”

“…The results of ref. 31 have been explained in terms of the modified Marcus theory. In particular, it has been shown that interaction of molecular dipoles with their mirror images reduces the dipole energy the same way as modification of the local dielectric permittivity does, leading to the reduction of the reaction rates.…”