Theoretical studies on anisotropic charge mobility, band structure, and non-linear optical calculations of ambipolar type organic semiconductors

TL;DR

This paper uses first-principle calculations and Marcus-Hush theory to analyze anisotropic charge mobility, band structure, and non-linear optical properties of phenancene-based organic semiconductors, highlighting TBT's ambipolar behavior and stability.

Contribution

It provides a theoretical analysis of charge mobility, band structure, and NLO properties of phenancene compounds, emphasizing the role of molecular packing and stability.

Findings

TBT exhibits high anisotropic charge mobility and ambipolar semiconducting behavior.

TBT shows superior non-linear optical response compared to DBP.

The studied compounds have higher HOMO levels and better air-stability than pentacene.

Abstract

The anisotropic charge carrier mobilities of two phenancene series compounds such as dibenzo[a,c]picene (DBP) and tribenzo[a,c,k]tetraphene (TBT) is investigated based on the first-principle calculations and Marcus-Hush theory. The molecular packing patterns in organic crystal play an important role for determing the charge carrier mobility and hence the device efficiencies designed from the organic materials. Among the studied molecules, TBT shows a maximum anisotropic hole ($\mu_h=0.129\ cm^2V^{-1}s^{-1}$) and electron ($\mu_h=1.834\ cm^2V^{-1}s^{-1}$) mobility, hence possesses an ambipolar semiconducting character. The frontier molecular orbital analyses proved the better air-stability of the studied compounds than the conventional pentacene, because of their higher HOMO energy levels. Band structure calculations of the studied compounds have also been investigated. From non-linear optical (NLO) properties anysis, we found the TBT compound shows more NLO response than DBP.