Tunable Semiconductors: Control over Carrier States and Excitations in Layered Hybrid Organic-Inorganic Perovskites

TL;DR

This paper predicts how changing organic and inorganic parts in layered hybrid organic-inorganic perovskites can systematically control carrier states, energy levels, and excitations, enabling tunable optoelectronic properties.

Contribution

It introduces a first-principles approach to predict and control carrier states and energy level alignments in layered hybrid perovskites through organic-inorganic component variation.

Findings

Carrier states can be tuned via organic-inorganic component variation.

Energy level alignments can be systematically controlled.

Transport and recombination properties are adjustable.

Abstract

For a class of 2D hybrid organic-inorganic perovskite semiconductors based on $\pi$-conjugated organic cations, we predict quantitatively how varying the organic and inorganic component allows control over the nature, energy and localization of carrier states in a quantum-well-like fashion. Our first-principles predictions, based on large-scale hybrid density-functional theory with spin-orbit coupling, show that the interface between the organic and inorganic parts within a single hybrid can be modulated systematically, enabling us to select between different type-I and type-II energy level alignments. Energy levels, recombination properties and transport behavior of electrons and holes thus become tunable by choosing specific organic functionalizations and juxtaposing them with suitable inorganic components.