Multiple-Route Exciton Recombination Dynamics and Improved Stability of Perovskite Quantum Dots by Plasmonic Photonic Crystal

Abstract

We have studied the excited-state exciton recombination dynamics of perovskite quantum dots (QDs) through time-resolved photoluminescence (PL), PL blinking, PL intensity-dependent lifetime modulation, and long-term photostability tests. The various spectroscopic characterizations elucidate that the perovskite QDs have multiple intrinsic exciton recombination routes even in a single QD, i.e., exciton, biexciton, and positive/negative trions, which are dissimilarly contributed to ON and OFF state emissions. We also find that the enhanced radiative recombination from placing green QDs on a photonic Ag nanotip array induces notably improved long-term PL stability. We consider that the accelerated radiative recombination of QDs by strong coupling with the plasmonics of the photonic Ag nanotip array, while eliminating nonradiative pathways, is proven to be a critical factor for improved long-term stability.

Unraveling chirality transfer mechanism by structural isomer-derived hydrogen bonding interaction in 2D chiral perovskite

“…A bi-exponential fitting was used to extract the lifetimes and relevant parameters were presented in Table S4 . Both of chiral RP OIHPs have slow lifetime components associated with recombination in the lattice interior in the range of a few nanoseconds (2.068 ns for 1NEA sample and 1.985 ns for 2NEA sample) 7 , 44 . This reveals that free exciton relaxes very fast due to the large exciton binding energy in 2D chiral RP OIHPs.…”

Off-State-Free and Stable InP/ZnSe/ZnS Quantum Dots Enabled by Effectively Suppressing the Leakage of Charge Carriers

“…In QDs with a thin ZnS shell (InP/ZnSe/ZnS-1.1 ML), the average lifetime decreased to 80 ns after purifications compared to the unpurified QDs (86 ns), primarily due to the emergence of the new fast decay component (τ1 = 2.4 ns) (Figure a and Table S1). This fast decay component observed after purifications can be attributed to a nonradiative process (presumably charge trapping) associated with surface traps created after purification, possibly due to the detachment of surface ligands. ,− We note that, based on electron paramagnetic resonance (EPR) data, the number of traps generated after purifications can be small (Figure S8). Also note that the contribution of the fast component is remarkably high (9.2%) in InP/ZnSe/ZnS-1.1 ML (Table S1).…”