Short and Long-Range Electron Transfer Compete to Determine Free-Charge Yield in Organic Semiconductors

Abstract

Understanding how Frenkel excitons efficiently split to form free-charges in low-dielectric constant organic semiconductors has proven challenging, with many different models proposed in recent years to explain this phenomenon. Here, we present evidence that a simple model invoking a modest amount of charge delocalization, a sum over the available microstates, and the Marcus rate constant for electron transfer can explain many seemingly contradictory phenomena reported in the literature. We use an electron-accepting fullerene host matrix dilutely sensitized with a series of electron donor molecules to test this hypothesis. The providing a mechanistic explanation for why Marcus-inverted-behavior is rarely observed in device studies.

A Theoretical Investigation of Charge Transfer Dynamics from Sensitized Molecule D35CPDT Dye to SnO_2 and TiO_2 Semiconductor

“…It further influences on charge transfer rate. Furthermore, we find the results in for D35CPDT / 𝑇𝑖𝑂 2 .Table (5) shows the potential in both systems increasing with the decrease of the transition energy and the charge transfer rate will be increasing tremendously with the decrease of the potential energy. The results in Table (6) indicate that D35CPDT contact to 𝑆𝑛𝑂 2 with Methanol solvents at driving energy 0.6eV giving us a large rate compared to the results in a table (7) or D35CPDT contact to 𝑇𝑖𝑂 2 with Methanol solvent and the D35CPDT / 𝑆𝑛𝑂 2 is a good system and can be used in electronic devices.…”

“…(11). Results are listed in the table (5) for D35CPDT / 𝑆𝑛𝑂 2 the system with the driving energy ∆𝐹 0 (𝑒𝑉) = 0.6 eV and D35CPDT / 𝑇𝑖𝑂 2 system with the driving energy∆𝐹 0 (𝑒𝑉) = 1.25 𝑒𝑉, respectively . To understand the charge transfer properties, it has been pointed to calculate the charge transfer rate (Κ 𝐶𝑇𝑅 ) associated with the transition energy Λ(eV)of D35CPDT/ 𝑆𝑛𝑂 2 and D35CPDT/ 𝑇𝑖𝑂 2 .…”

“…Since O'Regan and Gratzel introduced a work in1990s,dye-sensitized solar cell DSSCs are attracting more attention to convert light to electricity at a low cost [4]. The dye-sensitized had been excitation by light-induced due to absorbed light and the electrons will be transferred from the dye to the conduction band of the semiconductor [5]. The electron transfer process is an important fundamental reaction in different devices and dye-sensitized solar cell devices [6].…”

“…A basic classical theory for the charge transfer process was introduced by Rudolph Marcus to describe the transfer between two states donor and acceptor and was awarded Nobel Prize in 1992 [7]. The dye-sensitized had been excited by light-induced due to absorbed light, and the electrons will be transferred from the dye to the semiconductor's conduction band [5]. The electron transfer process is an important fundamental reaction in different devices and dye-sensitized solar cell devices [6].…”