Solid-State Infrared Upconversion in Perylene Diimides Followed by Direct Electron Injection

In this contribution we demonstrate a solid-state approach to triplet-triplet annihilation upconversion for application in a solar cell device in which absorption of near-infrared light is followed by direct electron injection into an inorganic substrate. We use time-resolved microwave photoconductivity experiments to study the injection of...

Interplay between Charge Carrier Mobility, Exciton Diffusion, Crystal Packing, and Charge Separation in Perylene Diimide-Based Heterojunctions

Two of the key parameters that characterize the usefulness of organic semiconductors for organic or hybrid organic/inorganic solar cells are the mobility of charges and the diffusion length of excitons. Both parameters are strongly related to the supramolecular organization in the material. In this work we have investigated the relation...

Charge Carrier Dynamics in Cs₂AgBiBr₆ Double Perovskite

Double perovskites, comprising two different cations, are potential nontoxic alternatives to lead halide perovskites. Here, we characterized thin films and crystals of Cs₂AgBiBr₆ by time-resolved microwave conductance (TRMC), which probes formation and decay of mobile charges upon pulsed irradiation. Optical excitation...

Computational Design of Two-Dimensional Perovskites with Functional Organic Cations

Two-dimensional (2D) halide perovskites are a class of materials in which 2D layers of perovskite are separated by large organic cations. Conventionally, the 2D perovskites incorporate organic cations as spacers, but these organic cations also offer a route to introduce specific functionality in the material. In this work, we demonstrate, by...

Band-Like Charge Transport in Cs₂AgBiBr₆ and Mixed Antimony-Bismuth Cs₂AgBi_{1- x}Sb_xBr₆ Halide Double Perovskites

Recently, halide double perovskites (HDPs), such as Cs₂AgBiBr₆, have been reported as promising nontoxic alternatives to lead halide perovskites. However, it remains unclear whether the charge-transport properties of these materials are as favorable as for lead-based perovskites. In this work, we study the mobilities of...

Interconversion between Free Charges and Bound Excitons in 2D Hybrid Lead Halide Perovskites

The optoelectronic properties of hybrid perovskites can be easily tailored by varying their components. Specifically, mixing the common short organic cation (methylammonium (MA)) with a larger one (e.g., butyl ammonium (BA)) results in 2-dimensional perovskites with varying thicknesses of inorganic layers separated by the large organic cation...

Direct-indirect character of the bandgap in methylammonium lead iodide perovskite

Metal halide perovskites such as methylammonium lead iodide (CH₃ NH₃ PbI₃) are generating great excitement due to their outstanding optoelectronic properties, which lend them to application in high-efficiency solar cells and light-emission devices. However, there is currently debate over what drives the second...

Effect of cation rotation on charge dynamics in hybrid lead halide perovskites

Organic-inorganic hybrid halide perovskites are a promising class of materials for photovoltaic application with reported power efficiencies over ∼22%. However, not much is known about the influence of the organic dipole rotation and phase transitions on charge carrier dynamics. Here, we report substantial changes in mobility and lifetime of...

High charge carrier mobility and efficient charge separation in highly soluble perylenetetracarboxyl-diimides

In this communication we report on the synthesis and charge mobility of highly soluble perylenebisimid derivatives.We show that introduction of alkylester side chains results in compounds combining a high solubility with charge mobilities up to 0.22 cm2 V_1 s_1. These materials are therefore interesting as an electron acceptor for solution...

Effect of intermolecular disorder on the intrachain charge transport in ladder-type poly( p -phenylenes)