Dynamics of Photo-Generated Carriers across the Interface between CsPbBr₃ Nanocrystals and Au–Ag Nanostructured Film, and Its Control via Ultrathin MgO Interface Layer

Abstract

The dynamics and control of charge transfer between optoelectronically interesting and size-tunable halide perovskite quantum dots and other juxtaposed functional electronic materials are important issues for the emergent device interest involving such a family of materials in heterostructure configurations. Herein, we have grown bimetallic Au−Ag thin films on glass by pulsed laser deposition at room temperature, which bear nanoparticulate character, and the corresponding optical absorption spectra reveal the expected surface plasmon resonance signature(s). Subsequently, spin-coated CsPbBr 3 nanoparticle films onto the bimetallic Au−Ag films exhibit surface-enhanced Raman scattering as well as strong photoluminescence quenching, the latter reflecting highly efficient transfer of photo-generated carriers across the CsPbBr 3 /Au−Ag interface. Surprisingly, when an ultrathin MgO (insulating) layer of optimum thickness is introduced between the CsPbBr 3 and Au−Ag films, the charge transfer is further facilitated with the average lifetime of carriers becoming even shorter. By changing the thickness of the thin MgO layer, the carrier lifetime can in fact be tuned; with the charge transfer getting fully blocked for thick enough MgO layers, as expected. Our study thus throws light on the charge-carrier dynamics in halide perovskites, which is of importance to emergent optoelectronic applications.

An Organic–Inorganic Perovskitoid with Zwitterion Cysteamine Linker and its Crystal–Crystal Transformation to Ruddlesden‐Popper Phase

“…Also, the average life time (Figure 8 D) of compound 1 which was reduced from 37.84 ns to 12.34 ns with the addition of FLBP showed a significant recovery back to 29.97 ns (Table S3) upon addition of 1.79×10 −3 M concentration of Ni 2+ . The bi‐exponentially fitted slow component (for radiative recombination) [64] of compound 1 reduced from 39.11 ns (52.8 %) to 16.80 ns (21.0 %) upon compositing with FLBP, which upon addition of Ni 2+ ions is seen to recover to 32.70 ns (62.2 %). These findings corroborate well with the PL quenching and recovery discussed above.…”

“…Thep reparation procedure of metaloleates for this study was adopted from the reported literature. [62] ThePLmodification by the addition of different ) for other transition elements.Since for all the cases the nature of PL is similar to that of the parent compound 1,t he transition element interaction with the perovskitoid is of primary importance for PL changes.A lso,t he average life time (Figure 8D)o fc ompound 1 which was reduced from 37.84 ns to 12.34 ns with the addition of FLBP showed as ignificant recovery back to 29.97 ns (Table S3) upon addition of 1.79 10 À3 Mc oncentration of Ni 2+ .T he biexponentially fitted slow component (for radiative recombination) [64] of compound 1 reduced from 39.11 ns (52.8 %) to 16.80 ns (21.0 %) upon compositing with FLBP,w hich upon addition of Ni 2+ ions is seen to recover to 32.70 ns (62.2 %). These findings corroborate well with the PL quenching and…”

An Organic–Inorganic Perovskitoid with Zwitterion Cysteamine Linker and its Crystal–Crystal Transformation to Ruddlesden‐Popper Phase

“…Thec orresponding PL spectra are shown in Figure 8B for various cases of interest. It was noted that Ni 2+ renders ar emarkable (almost full) recovery of PL, while the recovery is either negligible (Cu 2+ )o rs mall (Zn 2+ and Co 2+ ) for other transition elements.Since for all the cases the nature of PL is similar to that of the parent compound 1,t he transition element interaction with the perovskitoid is of primary importance for PL changes.A lso,t he average life time (Figure 8D)o fc ompound 1 which was reduced from 37.84 ns to 12.34 ns with the addition of FLBP showed as ignificant recovery back to 29.97 ns (Table S3) upon addition of 1.79 10 À3 Mc oncentration of Ni 2+ .T he biexponentially fitted slow component (for radiative recombination) [64] of compound 1 reduced from 39.11 ns (52.8 %) to 16.80 ns (21.0 %) upon compositing with FLBP,w hich upon addition of Ni 2+ ions is seen to recover to 32.70 ns (62.2 %). These findings corroborate well with the PL quenching and 2+ detection is an important result because humans exposed to nickel inhalation or Ni internalization via oral, and dermal routes can cause several severe health problems if nickel exposure exceeds certain limit.…”

In-situ monitoring of plasmon-induced nanoscale photocatalytic activity from Au-decorated TiO2 microflowers

“…For the Au-decorated samples, the peaks are deconvoluted into two peaks, as shown in figure S2. Apart from the defect peak, the Au-decorated TiO 2 samples have another peak in the visible region, which corresponds to the LSPR of Au, as shown in the shaded square of figure 7(b) and re-plotted in the inset [53]. In the TA-2 sample, the SPR peak is at a higher wavelength (498 nm) than the TA-4 (495 nm) and TA-6 (489 nm) samples, as discussed in the supplementary information.…”