Charge Transfer Dynamics of Two-Dimensional Ruddlesden Popper Perovskite in the Presence of Short-Chain Aromatic Thiol Ligands

Abstract

Two-dimensional (2D) Ruddlesden Popper perovskites (RPP) are highly important in light-harvesting and photovoltaic applications. The formation of a repetitive quantum well structure by alternating organic and inorganic layers leads to dielectric confinement of charges, which essentially inhibits the effective charge transport. In this work, we have investigated the impact of bifunctional short-chain aromatic ligands, namely, 4-aminothiophenol (ATP) and 4-nitrothiophenol (NTP), on the charge transfer dynamics of 2D RPP. The electron transfer from 2D RPP to NTP and the hole transfer from 2D RPP to ATP are evident from ultrafast transient absorption spectroscopy, depending on the nature of ligands, and the electron transfer and hole transfer occur in 900 fs and 1.9 ps, respectively. Our results provide insights for understanding the charge transfer dynamics in the presence of short-chain aromatic thiol ligands with 2D RPP, which will facilitate the performance of next-generation optoelectronic devices.

Impacts of Exciton Binding Energy and Dielectric Confinement of Layered Lead Halide Perovskites on Carrier Relaxation and Exciton Phonon Interactions

“…9,48 The PIA 1 signal arises for absorption of the carrier in the band edge state, and PIA 2 appears due to the band gap renormalization process. 6,26,49,50 For our case, the GSB signals are located at 522, 517, and 510 nm for (BA) 2 PbI 4 , (HA) 2 PbI 4 , and (OA) 2 PbI 4 LPs, respectively, which are matched with steady-state optical absorption results. The bleach and its consequent recovery are fitted by the Gaussian modified exponential function and the time constant with its contribution associated with this ultrafast process yields.…”

“…1−5 In general, the twodimensional (2D) nature of LPs is constructed with alternating layers between negatively charged inorganic layers (well) and positively charged organic layers (barrier). 3,5,6 The photophysical properties of LPs, such as hot carrier relaxation dynamics, carrier recombination process, charge transfer dynamics, etc., are tuned by engineering inorganic and organic layers. 7−9 Notably, the barrier cations noncovalently interact with the inorganic layers and accelerate to distort the packing of the inorganic layer in the quantum well structure that affects the optical properties.…”

Tailoring Interlayer Charge Transfer Dynamics in 2D Perovskites with Electroactive Spacer Molecules

“…Moreover, it rationalizes the weak PL (Figure f) as the hole transfer process results in the electron and hole wavefunctions being spatially separated, giving rise to a reduced radiative decay probability. This observation is similar to the CT-induced PL quenching observed in napthalenediimide-based , and thiophene-based 2D perovskites, and in a thiol-coupled 2D perovskite . In contrast, the electron and hole remain strongly bound and localized on the inorganic layer in (PEA) 2 PbI 4 , resulting in efficient PL at the exciton transition .…”

Electron Transfer Dynamics from CsPbBr3 Nanocrystals to Au144 Clusters

“…Hence, the faster HC relaxation in the hybrid system occurs due to hot electron transfer from CsPbBr 3 nanocrystal to Au NCs, not due to the surface-related defect/trap states. Besides, we have estimated the hot electron transfer rate by the following equation k hot‐electron = 1 τ hybrid growth − 1 τ CsPbBr 3 growth The calculated hot-electron transfer rate from CsPbBr 3 nanocrystals to Au 144 NCs in a hybrid system is 1.05 × 10 12 s –1 .…”