Photon-Energy-Dependent Reversible Charge Transfer Dynamics of Double Perovskite Nanocrystal-Polymer Nanocomposites

Abstract

Combining steady-state photoluminescence and transient absorption (TA) spectroscopy, we have investigated the photoinduced charge transfer dynamics between lead-free Mn-doped Cs2NaIn0.75Bi0.25Cl6 double perovskite (DP) nanocrystals (NCs) and conjugated poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV). Upon ultraviolet-A excitation, the photoinduced absorption feature of DP NCs/MDMO-PPV nanocomposites disappeared, and the stimulated emission weakened in the TA spectrum. This was due to charge transfer from the MDMO-PPV polymers to DP NCs. Upon a higher photon-energy ultraviolet-C excitation, stimulated emission and photoinduced absorption features vanished, indicating there existed a reversible charge transfer from DP NCs to MDMO-PPV polymers. Reversible charge transfer of Mn-doped DP NCs/MDMO-PPV nanocomposites was tuned by varying the excitation photon-energy. The manipulation of reversible charge transfer dynamics in the perovskite-polymer nanocomposites opens a new avenue for optical and optoelectronic applications.

Transient Absorption Analysis on Energy Transfer from Carbon Quantum Dots to Tungsten Disulfide

“…In order to avoid interference, the TA kinetics at 440 and 570 nm had been considered as the intrinsic state and defect state in TA experiment. TA kinetic containing both SE and PIA features can be well fitted by the following biexponent decay formula 39 (2)…”

“…In order to avoid interference, the TA kinetics at 440 and 570 nm had been considered as the intrinsic state and defect state in TA experiment. TA kinetic containing both SE and PIA features can be well fitted by the following biexponent decay formula f ( t ) = f 0 + p 1 exp ( − t / τ PIA ) − p 2 exp ( − t / τ SE ) where τ PIA and τ SE were their lifetimes, and p 1 and p 2 were the corresponding weight factors, respectively. The single exponential decay function can be used to better fit the SE feature with only p 1 = 0.…”