Energy Funneling from Water-Dispersed Perovskites to Chromophores

Abstract

Cesium lead halide perovskite nanocrystals (PNCs) have enjoyed enormous attention in optoelectronics and photovoltaics. However, instability under polar conditions and limited energy/charge transport due to long-chain capping ligands restrict their large-scale applications. We have engineered a short-chain multidentate bolaamphiphilic ligand (NKE-3), which provides synergistic passivation of the perovskite surface by one multidentate ionic terminal and localizes water molecules by another multidentate ionic terminal, leading to a watersuspended colloidal solution of PNCs. NKE-3 allows efficient long-range dipole-based fluorescence resonance energy transfer (FRET) from perovskites to Rhodamine B isothiocyanate (RITC) in water, with FRET efficiencies ranging from 96% to 98%. We calculated the FRET rate using the acceptor's rise-time component, as it ensures no contamination from FRET-inactive donors. Moreover, we tuned the emission maxima of PNCs through halide exchange to optimize FRET efficiency. Such energy funneling to a suitable molecular photocatalyst is imperative for PNCs' potential applications.

Synergistic binding between an engineered interface and functionalized ferrocene offers remarkable charge extraction efficiency in lead halide perovskites

“…Moreover, a signicant decrease in the intensity of the peaks at 1399 cm −1 and 1527 cm −1 indicating the symmetric and asymmetric vibrations of the carboxylate group from the complexed oleate anions, as well as the appearance of a weak peak at 1738 cm −1 due to free oleic acid (-C]O stretching), conrm the desorption of the oleic acid ligand from the surface of CPB NK-12. Additionally, the strong absorbance at 1662 cm −1 and 1635 cm −1 in CPB NK-12 corresponds to the -C]O stretch from amide 70 and NH 3 + stretch, respectively, which are also present in pure NK-12 (Fig. S3a †).…”

“…S11b †) were tted with two binding energy peaks at 399.74 eV and 401.65 eV, corresponding to -NH 2 and -NH 3 + , respectively. 73 The well-dened N 1s peaks in CPB NK-12 suggest an effective ligand exchange between NK-12 and more dynamic native OAm/OAc ligands. We used the time-resolved PL (TRPL) technique to understand the effect of ligand exchange on different electron-hole recombination channels and determine the PL lifetime of CPB.…”

“…Although PLQY values are comparable for CPB and CPB NK-12, the NK-12 ligand has been shown to enhance passivation of CPB (OAm/OAc capped) in toluene as discussed in our previous report. 73 Next, we performed a series of experiments to study the effect of NK-12 on interfacial interactions with our previously designed ferrocene-based surfactant having a COOH anchoring group (FcS4). 49 The absorbance spectra of CPB and CPB NK-12 (∼12.9 nM for both NCs) in toluene were recorded with the progressive addition of FcS4 (Fig.…”

Design Principle of a Water-Dispersed Photocatalytic Perovskite through Ligand Deconstruction

“…However, the ligands employed as capping agents majorly include long-chain oleyl amine/oleic acid (OAm/OAc) dispersed in organic solvents, inhibiting charge transport due to their insulating nature. Therefore, ligand exchange strategies with short-chain ligands were explored to instigate better charge transport properties. ,, However, LHP NCs with short-chain ligands exhibited relatively lower colloidal stability. ,, In a nutshell, there exists a trade-off between colloidal stability and charge carrier transport from LHP NCs due to their ligand shells. So far, multidentate ligands have been deemed promising due to their multiple binding sites and improved surface coverage. − A few studies have also explored encapsulation strategies utilizing polymer, SiO 2 , semiconductor, or metal–organic framework matrixes to protect LHPs from moisture and the solvent environment. − However, designing an LHP system with purely ligand-dependent colloidal stability and intact photocatalytic activity in an aqueous medium remains a huge challenge.…”

“…21,38,39 However, LHP NCs with short-chain ligands exhibited relatively lower colloidal stability. 21,40,41 In a nutshell, there exists a trade-off between colloidal stability and charge carrier transport from LHP NCs due to their ligand shells. So far, multidentate ligands have been deemed promising due to their multiple binding sites and improved surface coverage.…”