Elucidating the Size‐dependent FRET Efficiency in Interfacially Engineered Quantum Dots Attached to PBSA Sunscreen

Abstract

Applying sunscreen on human skin provides photoprotection against the harmful ultraviolet (UV) radiation of the sun. Sunscreen absorbs UV radiations and dissipates the absorbed energy through various radiative and nonradiative pathways. The attachment of functionalized quantum dots (QDs) to the sunscreen component is a novel idea to enhance the absorption cross-section of UV radiations. Therefore, the attachment of the sunscreen component to the ligand functionalized biocompatible QDs and the absorbed energy transfer from sunscreen to the QDs could work as a model system to overall improve the efficiency of the sunscreen. This study elucidates the mechanism of size-dependent Förster resonance energy transfer (FRET) efficiency and its rate between 2phenylbenzimidazole-5-sulfonic acid (PBSA) and mercaptoacetic acid (MAA) functionalized CdS QDs. In the PBSA-QDs dyad, the PBSA (donor) dissipates UV-absorbed energy to the CdS QDs (acceptor). Following excitation at 306 nm, the steady-state photoluminescence (SSPL) and time-resolved photoluminescence (TRPL) techniques measurements demonstrate that both the nonradiative energy transfer efficiency and rate are QDs size-dependent in addition to donoracceptor distance, and suggest that bigger sized-QDs result in an increase of the FRET efficiency.

Enhancing the FRET by tuning the bandgap of acceptor ternary ZnCdS quantum dots

“…6(a), suggesting the large magnitude of FRET efficiency (69.74%), Table 2, which is significantly higher than the previously reported literature values 67.3% (ref. 42) and 64.05%. 44 It is evident from Table 2 that MAA functionalized ZnCdS QDs coupled with ensulizole have a high value of energy dissipation through the non-radiative FRET pathway.…”

“…The UV-absorbed energy transfer efficiency from ensulizole sunscreen to the QDs is ∼70%, which is significantly higher than the efficiencies of 67.3% (ref. 42) and 64.05% (ref. 44) reported in the previous works.…”

“…41 Recently, the effect of size of CdS QDs as a FRET acceptor antagonist on a sunscreen donor has been reported. 42 Very recently, the work of Cowden et al 43 reveals that the combination of two sunscreen molecules into one composite sunscreen forms a product with good stability towards UV light absorption and its dissipation in ethanol and bestows advantages over single-component of sunscreens. 43 In this article, we investigate the surface modication of ZnCdS QDs by varying the concentration of capping ligand that tunes the photophysical properties of QDs.…”

Cu-Enhanced Efficient Förster Resonance Energy Transfer in PBSA Sunscreen-Associated Ternary CuxCd1–xS Quantum Dots

“…To further understand the FRET process, the PL quenching analysis of PBSA is performed by measuring its PL intensity and PL decay kinetics in both the absence and presence of various concentrations of CCS QDs (5,10,15,20, and 25 mM) in phosphate buffer. To determine the mechanism of PL quenching, the well-known Stern−Volmer's (SV) equation 30 is used (eq 7) ) where τ o and τ are the PL decay lifetimes of the donor in the absence and presence of the acceptor, respectively.…”

“…Owing to the distinct and unique properties of QDs, they are widely used in fluorescence biosensors, photocatalysts, drug delivery, bioimaging, and optoelectronic devices, such as solar cells, light-emitting diodes, and lasers . Although the binary semiconductor QDs are widely used, recently, alloyed (ternary and quaternary) QDs have been at the prime focus because of their potential applications that can be tuned by controlling the constituent stoichiometries and internal structure. ,, More recently, Cu-based II–VI semiconductor nanocrystals such as Cu x Cd 1− x S (CCS) have emerged as promising candidates due to their specific advantages relative to their corresponding binary counterparts CuS and CdS, which allow tuning the desirable optoelectronic properties . In addition, Cu chalcogenide QDs are inexpensive, stabilized under photoirradiation, moisture and oxygen, biocompatible, and durable. − …”