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Professor Dong Xiangting & Associate Professor Xie Yunrui from Changchun University of Science and Technology in Matter: "Parallel+Uniaxial" Conjugated Electrospinning for Dual-Function Analogous-Tricolor Microfiber Film with Multicolor Emission and Magnetism
Lead halide perovskite CsPbX3 (X = Cl, Br, I) quantum dots (QDs) have attracted researchers' interest due to their applications in light-emitting diodes (LEDs), solar cells, fluorescent sensors, and photocatalysis. However, to further expand their applications, developing multifunctional materials based on perovskite QDs is significant. Notably, conventional preparation methods often directly blend different functional substances, which may cause undesirable interactions that compromise multifunctionality. Therefore, it's necessary to design and construct special one-dimensional structures that effectively separate luminescent substances from dark magnetic materials or different perovskite QD components at the microscale to avoid direct contact and achieve better multifunctionality.
Recently, Professor Dong Xiangting and Associate Professor Xie Yunrui from Changchun University of Science and Technology published their latest research in Matter: ""Parallel+uniaxial" conjugated electrospinning for dual-function analogous-tricolor microfiber film with multicolor emission and magnetism". The researchers proposed an innovative "parallel+uniaxial" conjugated electrospinning technique to synthesize a unique {[CsPbBr3/polystyrene (PS)]//[CoFe2O4/PS]}||[CsPb(Br0.06/I0.94)3/PS] analogous-tricolor microfiber film (ATMF) with multicolor emission and tunable magnetism. Figure 1 shows the synthesis of CsPbBr3 QDs, CsPb(Br0.06/I0.94)3 QDs, spinning solutions, and the preparation flowchart and composition diagram of ATMF. The design concept and preparation technology may provide new ideas for synthesizing other novel perovskite QD multifunctional materials. Ph.D. candidate Huo Xintong is the first author, with Professor Dong Xiangting and Associate Professor Xie Yunrui as corresponding authors.
Figure 1: Schematic diagrams of synthesis processes for CsPbBr3 QDs, CsPb(Br0.06/I0.94)3 QDs and spinning solutions, and preparation of tricolor-like microfibers and ATMF.
As shown in Figure 2, the prepared ATMF exhibits excellent fiber morphology. The tricolor-like microfibers as building units achieve three independent microscopic compartments, confining green-emitting CsPbBr3 QDs, red-emitting CsPb(Br0.06/I0.94)3 QDs, and magnetic CoFe2O4 to their respective partitions, thereby avoiding the adverse effects of dark CoFe2O4 on the fluorescence of both perovskite QDs. The microspatial separation of the two perovskite QDs prevents halogen anion exchange between them, achieving fluorescence-magnetism dual functionality.
Figure 2: SEM image of ATMF (a); Optical microscope (LM) and fluorescence microscope (FM) images of tricolor-like microfibers (b); EDS line analysis (c).
As shown in Figure 3, in ATMF, while changing the content of magnetic CoFe2O4 and green-emitting CsPbBr3 QDs, the emission peak positions and shapes of perovskite QDs remain essentially unchanged, but the fluorescence intensity at 517 nm varies, enabling ATMF to transition from green to yellow emission for multicolor luminescence.
Figure 3: Fluorescence spectra and CIE chromaticity diagrams of ATMF with different CoFe2O4 contents (A, B) and different CsPbBr3 contents (C, D).
Fluorescence performance comparisons show that compared with control samples, this specially designed tricolor-like structure has structural advantages and better fluorescence performance, avoiding both the adverse effects of magnetic materials on fluorescent substances and halogen anion exchange between perovskite QDs, achieving two goals with one action.
Figure 4: Fluorescence spectra of ATMF and control samples (a); CIE chromaticity diagram of control samples (b); Schematic diagram of fluorescence emission from tricolor-like microfibers in ATMF (c).
As shown in Figure 5, by adjusting the content of magnetic CoFe2O4 in ATMF, tunable magnetism can be obtained while maintaining fluorescence performance (Figures 5a and 5c-5e). Additionally, as an application demonstration, LEDs packaged with blue chips and ATMF can achieve white light emission (Figure 5b).
Figure 5: Hysteresis loops of ATMF with different CoFe2O4 contents (a); Electroluminescence (EL) spectrum of ATMF with blue chip (b); Visual demonstrations of magnetism (c, d) and fluorescence (e) for ATMF doped with different ratios of perovskite QDs under no magnet contact (c), magnet attraction (d), and magnet attraction under UV lamp irradiation (e).
