Insulating CsPbBr₃ Quantum Dots via Encapsulation with SiO_x: Interfacial Electron Trafficking and Interaction beyond the Insulating Boundary

Abstract

Dense and long-chain ligands on the surface of lead halide perovskite quantum dots (PQDs) hinder charge transport. Thus, it is extremely challenging to achieve environmentally stable PQDs with an appropriate ligand, optimal density, and successful charge transfer to charge acceptors. Through comprehensive material development and photophysical experiments, rapid crystallization of CsPbBr 3 PQDs encapsulated in crude silica shells at room temperature was achieved using (3aminopropyl)triethoxysilane as the key coordinating ligand. Following the control post-annealing treatment, highly stable PQDs wrapped in robust insulating silica shells were obtained; they exhibited phenomenal electron transfer characteristics beyond silica shell coverage. Based on the electron transfer phenomenon from the core−shell PQDs to the electron transport media, the formation of photoinduced superoxide ions was demonstrated. These ions triggered the photocatalytic degradation of 2-mercaptobenzothiazole. This study presents advanced insights into core− shell CsPbBr 3 PQDs covered in silica shells and their detailed photochemistry for renewable energy applications.

Effect of the surroundings on the photophysical properties of CsPbBr3 perovskite quantum dots embedded in SiOx matrices

“…The PQD‐to‐PQD interdot energy transfer process can be speculated based on the corresponding PL peak shift phenomena. Furthermore, statistical demonstration of fluorescence lifetime shortening supported the additional evidence on the interaction of PQDs with the surroundings obtained by our preliminary study 31 . This work could contribute to the utilization of core–shell PQDs in solar‐driven chemistry and optoelectronic devices by elucidating the fundamental aspects of the dot‐to‐surrounding interactions.…”

“…Therefore, was longer than . The silica coverage edge thickness shown in Figure 1a was approximately 1.5 nm, according to our previous study 31 . Note that CsPbBr 3 @SiO x PQDs were identically synthesized in our previous study.…”

“…Core–shell PQDs were applied to both solar‐driven chemistry and LEDs. Our group recently elucidated the formation mechanism of the core–shell CsPbBr 3 PQD s @SiO x and the charge transfer kinetics of ETMs (TiO 2 and O 2 ) and successfully used the PQDs@SiO x for the photocatalytic degradation of carcinogens 31 . Our results demonstrated that the PQD core could interact with ETMs/carcinogens beyond silica shell coverage.…”

“…The basic material aspects of CsPbBr 3 @SiO x PQDs were studied before the effect of the surroundings on CsPbBr 3 @SiO x PQDs. Following our previous synthetic procedure to fabricate CsPbBr 3 @SiO x PQDs, 31 we identically synthesized the CsPbBr 3 @SiO x PQDs, as perovskite cores were covered in the amorphous SiO x shells and the core–shell PQDs were physically aggregated. Figure 1 shows the formation of 5–10 nm PQDs in the SiO x matrix, cubic CsPbBr 3 core structure, and absorption band edge with the PL spectrum appearing at 510 nm.…”

“…We adopted the synthetic procedure from our recent study 31 . In summary, the aforementioned 0.1 ml CsPbBr 3 DMF precursor solution was quickly added into 10 ml of toluene and placed in a 50 ml centrifuge tube under stirring.…”