Ultrafast charge transfer enhanced nonlinear optical properties of CH₃NH₃PbBr₃ perovskite quantum dots grown from graphene

Abstract

Halide perovskite quantum dots (PQDs) have exhibited significantly superior nonlinear optical properties compared to traditional semiconductor materials thanks to their peculiar physical and electronic structures. By further improving the nonlinear optical properties of PQDs, it is expected to adapt to ultrafast photonics applications. This work reported the nonlinear optical properties of methylammonium lead bromide-graphene (CH3NH3PbBr3-G) composites synthesized by growing CH3NH3PbBr3 quantum dots directly from a graphene oxide lattice. Our experiments indicate that the combined advantages of the ultrafast charge transport properties from graphene and the strong charge generation efficiency of perovskite can be integrated together. The CH3NH3PbBr3-G composite exhibited enhanced saturable absorption properties with large modulation depth and very low saturation intensity. The transient absorption spectra and carrier dynamics analysis revealed that the enhancement of the saturated absorption properties of the composites mainly arose from the ultrafast charge transfer between G and CH3NH3PbBr3 which promoted the coupling between different states. The results pave the way for the design of optical switches or mode lockers based on saturable absorbers with good performance.

Indium-Tin-Oxide-Induced Tunability of Nonlinear Optical Absorption from CH3NH3PbBr3 Nanostructure-Based Films: Implications for Nonlinear Optical Devices

“…Figure a shows the full XPS spectrum of MAPbBr 3 film samples with and without ITO buffer layers. The successful preparation of MAPbBr 3 films was demonstrated by the two typical XPS peaks of Pb 4f and Br 3d and the XPS peaks of C 1s and N 1s. , The characteristic peaks of the Pb 4f, Br 3d, and N 1s energy states of MAPbBr 3 and MAPbBr 3 /ITO were essentially the same, as shown in Figure b–d. The Br 3d spectra show two fitting peaks at 68.4 and 67.3 eV, corresponding to Br 3d 3/2 and Br 3d 5/2 , respectively.…”

“…The energy band gap of the film can be calculated by linear extrapolation of the Tauc plot to zero. , According to Figure b, it can be seen from the inset that the band gap of ITO was about 3.87 eV, while the band gaps of MAPbBr 3 and MAPbBr 3 /ITO were 2.29 and 2.31 eV, respectively. These values were very similar to the reported ones. ,, The band gaps of MAPbBr 3 and MAPbBr 3 /ITO are almost constant. This is due to fact that both exhibit the same absorption edge, and ITO does not change the phase of MAPbBr 3 .…”

“…MAPbBr 3 -G composite has saturable absorption characteristics with a high modulation depth. 19 nonlinear properties of samples with such lead halide perovskite composites were rarely reported.…”

Solvent Effect on the Photoinduced Intramolecular Charge–Transfer and Redox Potentials of Three Difuranones

“…At the molecular level PCT plays an important role in various natural systems for sustaining life, like photosystems I and II reactions , involved in photosynthesis, among various photoautotrophs. The PCT process also plays a key role in the working efficiency of various light-harvesting photovoltaic systems, , OLEDs, NLO, , photocatalytic materials for production and processing of various gases for cleaner fuels, , etc. Especially for light-harvesting applications, a fast charge-transfer (CT) process with a small driving force and a slow back CT is desirable .…”

Mass ratio-dependently tunable enhancement of the optical nonlinearities of SnO2/RGO composites

“…Zhao et al obtained superior optical limiting properties of graphene-PbS nanohybrid [14]. So far, this strategy has been applied in many studies and proved to be effective [15,16].…”