Reorganization Energy upon Controlled Intermolecular Charge‐Transfer Reactions in Monolithically Integrated Nanodevices

Abstract

Intermolecular electron‐transfer reactions are key processes in physics, chemistry, and biology. The electron‐transfer rates depend primarily on the system reorganization energy, that is, the energetic cost to rearrange each reactant and its surrounding environment when a charge is transferred. Despite the evident impact of electron‐transfer reactions on charge‐carrier hopping, well‐controlled electronic transport measurements using monolithically integrated electrochemical devices have not successfully measured the reorganization energies to this date. Here, it is shown that self‐rolling nanomembrane devices with strain‐engineered mechanical properties, on‐a‐chip monolithic integration, and multi‐environment operation features can overcome this challenge. The ongoing advances in nanomembrane‐origami technology allow to manufacture the nCap, a nanocapacitor platform, to perform molecular‐level charge transport characterization. Thereby, employing nCap, the copper‐phthalocyanine (CuPc) reorganization energy is probed, ≈0.93 eV, from temperature‐dependent measurements of CuPc nanometer‐thick films. Supporting the experimental findings, density functional theory calculations provide the atomistic picture of the measured CuPc charge‐transfer reaction. The experimental strategy demonstrated here is a consistent route towards determining the reorganization energy of a system formed by molecules monolithically integrated into electrochemical nanodevices.

Impact of Planar and Vertical Organic Field‐Effect Transistors on Flexible Electronics

“…[73][74][75][76] This particular use is quite evident since the electron mobility of the electroactive organic materials is highly sensitive to the physical stimuli and the chemical environment surrounding them. [46,77] In addition, molecular engineering approaches make the sensitivity and selectivity of these materials possible by the precise adjustments of pendant groups, functionalization with molecular receptors, or even integration with biomolecular systems. [75,78] Here, we review the recent progress of the OFET technology and some of the exciting, flexible electronic applications addressed by it.…”

Pushing On-Chip Photosensitivity Forward Using Edge-Driven Vertical Organic Phototransistors

“…Figure a exhibits the confocal laser scanning (CLS) microscopy image (top view) of the entirely fabricated r -VOFET, also showing the labels of the source (S), drain (D), and gate (G) pads, and the rolled-up NM indicated by the arrow. On the active transistor area, the rolled-up NM mechanically contacts the DNTT thin film from the top, promoting a soft and reliable electrical contact, as previously described in the literature. − , At this region, all the layers are arranged vertically, with the vertical conducting channel formed within the OSC layer and between the source and drain electrodes. The material stacking along the dashed line is illustrated in the bottom schematics of Figure a, which also provides a complete cross-sectional view of the device’s active region.…”

“…In 2020, we proposed a novel approach, the rolled-up nanomembrane (NM)-based VOFET, referred to as r -VOFET, which employs a self-rolling NM as the top drain electrode, ensuring a soft and reliable electrical contact between the metal and the OSC ultra-thin film. − Thus far, the r -VOFET platform has one of the shortest conducting channels ( ca . 35 nm) ever reported in the literature .…”

Nonpolymer Organic Solar Cells: Microscopic Phonon Control to Suppress Nonradiative Voltage Loss via Charge-Separated State

“…The reorganization energies (λ = 0.89 eV in C4-DPP–H 2 BP +• :PC 61 BM –• and 0.55 eV in C4-DPP–ZnBP +• :PC 61 BM –• ) are required to self-consistently explain the gating effects for the different D:A systems and coincide with the broad 1 CT* emission bands in Figure . In addition, a recent study on the hole transfer reaction in copper-phthalocyanine crystalline films demonstrated that the reorganization energy for the intermolecular hopping is 0.93 eV . These strong reorganizations imply that the hole is not delocalized and undergoes quick hopping dissociation assisted by the phonon.…”

“…In addition, a recent study on the hole transfer reaction in copperphthalocyanine crystalline films demonstrated that the reorganization energy for the intermolecular hopping is 0.93 eV. 65 These strong reorganizations imply that the hole is not delocalized and undergoes quick hopping dissociation assisted by the phonon. As for V(r) = V 0 exp(−β(r − d)/2) of the separated RPs, McConnell's electron-tunneling model is applicable in β, as follows 66…”