Tailoring Interlayer Charge Transfer Dynamics in 2D Perovskites with Electroactive Spacer Molecules
Abstract
The family of hybrid organic-inorganic lead-halide perovskites are the subject of intense interest for optoelectronic applications, from light-emitting diodes to photovoltaics to X-ray detectors. Due to the inert nature of most organic molecules, the inorganic sublattice generally dominates the electronic structure and therefore optoelectronic properties of perovskites. Here, we use optically and electronically active carbazole-based Cz-Ci molecules, where Ci indicates an alkylammonium chain and i indicates the number of CH2 units in the chain, varying from 3-5, as cations in the 2D perovskite structure. By investigating the photophysics and charge transport characteristics of (Cz-Ci)2PbI4, we demonstrate a tunable electronic coupling between the inorganic lead-halide and organic layers. The strongest interlayer electronic coupling was found for (Cz-C3)2PbI4, where photothermal deflection spectroscopy results remarkably demonstrate an organic-inorganic charge transfer state. Ultrafast transient absorption spectroscopy measurements demonstrate ultrafast hole transfer from the photoexcited lead-halide layer to the Cz-Ci molecules, the efficiency of which increases by varying the chain length from i=5 to i=3. The charge transfer results in long-lived carriers (10-100 ns) and quenched emission, in stark contrast with the fast (sub-ns) and efficient radiative decay of bound excitons in the more conventional 2D perovskite (PEA)2PbI4, in which phenylethylammonium (PEA) acts as an inert spacer. Electrical charge transport measurements further support enhanced interlayer coupling, showing increased out-of-plane carrier mobility from i=5 to i=3. This study paves the way for the rational design of 2D perovskites with combined inorganic-organic electronic proper-ties through the wide range of functionalities available in the world of organics.
Cite
@article{arxiv.2306.09811,
title = {Tailoring Interlayer Charge Transfer Dynamics in 2D Perovskites with Electroactive Spacer Molecules},
author = {Yorrick Boeije and Wouter T. M. Van Gompel and Youcheng Zhang and Pratyush Ghosh and Szymon J. Zelewski and Arthur Maufort and Bart Roose and Zher Ying Ooi and Rituparno Chowdhury and Ilan Devroey and Stijn Lenaers and Alasdair Tew and Linjie Dai and Krishanu Dey and Hayden Salway and Richard H. Friend and Henning Sirringhaus and Laurence Lutsen and Dirk Vanderzande and Akshay Rao and Samuel D. Stranks},
journal= {arXiv preprint arXiv:2306.09811},
year = {2023}
}
Comments
16 main text pages + 20 supplemental text pages, 5 main text figures + 19 supplemental figures