Advanced Functional Materials and Devices (AFMD) Group

Abstract:

The data is in-situ spectroscopic ellipsometry data (mainly for psi and delta) used in the development and application of the DART method. CompleteEASE software from J.A.Woollam company was used for acquisition using RC2 Woollam ellipsometer, and exported in text document format. It can be imported using excel or in python.

Abstract:

Simultaneous control over both the energy levels and Fermi level, a key breakthrough for inorganic electronics, has yet to be shown for organic semiconductors. Here, energy level tuning and molecular doping are combined to demonstrate controlled shifts in ionisation potential and Fermi level of an organic thin film. This is achieved by p-doping a blend of two host molecules, zinc phthalocyanine and its eight-times fluorinated derivative, with tunable energy levels based on mixing ratio. The doping efficiency is found to depend on host mixing ratio, which is explained using a statistical model that includes both shifts of the host's ionisation potentials and, importantly, the electron affinity of the dopant. Therefore, the energy level tuning effect has a crucial impact on the molecular doping process. The practice of comparing host and dopant energy levels must consider the long-range electrostatic shifts to consistently explain the doping mechanism in organic semiconductors.