Long-Lived Hot Carriers in Two-Dimensional Perovskites: The Role of Alternating Cations in Interlayer Space

Abstract

Solar absorbers featuring prolonged hot-carrier (HC) cooling are highly desired for the development of HC solar cells. Two-dimensional (2D) hybrid perovskites are known for their exceptional stability and tunable optoelectronic properties. Nevertheless, their hot-carrier dynamics have been inadequately investigated. Here, we demonstrate ultraslow hot-carrier cooling with a lifetime >2 ns and long HC diffusion length in 2D (ACA)(MA)PbI 4 (ACA = acetamidinium) with alternating cations in the interlayer space (ACI), surpassing those of 3D MAPbBr 3 and 2D Ruddlesden−Popper (PEA) 2 PbI 4 . Our nonadiabatic molecular dynamics simulations with spin−orbit coupling show that the enhanced HC cooling in the ACI-phase 2D perovskite is due to multiple split-off bands and reduced electron−phonon coupling. Furthermore, the hot electrons can be efficiently extracted from (ACA)(MA)PbI 4 and then transferred to the electron-transporting layer. These new insights highlight the benefit of manipulating interlayer cations in 2D perovskites as an advantageous approach to control long-lived hot carriers, thus potentially enhancing photovoltaic device performance.

Structural Diversity in 2-(2-Aminoethyl)pyridine-Based Lead Iodide Hybrids

“…Our findings showcase that a similarity in molecular shape cannot be the only consideration when selecting donor–acceptor pairs. While most known ACI phases are mixed with organic cations of similar molecular shape, − Yan et al were able to achieve ACI phases by mixing alkyl and aryl cations, which have different molecular shapes . The presence of a dipole and hydrogen bonding should also be considered.…”

Cu–Zn Cation Disorder in Kesterite Cu2ZnSn(SxSe1–x)4 Solar Cells

“…NAMD simulations were performed with the decoherence-induced surface hopping (DISH) approach, as implemented in the PYXAID , package. This method has been proven to be reliable in simulating excited-state dynamics in CZTS/Se and other materials. − More theory details can be found in the Supporting Information (SI).…”