Journal: ACS Nano

Article Title: Controlled Synthesis of Perovskite Nanocrystals at Room Temperature by Liquid Crystalline Templates

doi: 10.1021/acsnano.4c13217

Figure Lengend Snippet: Controlled synthesis of perovskite nanocrystals in a liquid crystalline antisolvent. Chemical structures of (a) perovskite precursors (CH 3 NH 3 Br and PbBr 2 ) and organic ligands ( n -octylamine and oleic acid) and (b) the nematic liquid crystal (LC), E7. Schematic illustrations for reconstructed profiles of LC molecules (purple ellipsoids) around growing perovskite nanocrystals (PNCs) when their size L (blue double arrows) is (c) smaller and (d) larger than the extrapolation length ξ (red double arrows and circles) of the LCs. n indicates the director of LC. (e) Ultraviolet–visible absorbance (purple and blue lines) and photoluminescence (PL) spectra (red and black lines) measured from the LC-PNC (top) and T-PNC (bottom) solutions before (dashed lines) and after (solid lines) size purification processes. The PNCs are synthesized for 720 min at T = 25 °C. The insets show photographs of the as-synthesized PNC solutions under ambient light. a.u.: arbitrary units. (f) Size distribution of LC-PNCs (top) and T-PNCs (bottom) measured from electron micrographs. n ≥ 1000 measurements. L = 8 ± 2 nm (mean ± SD) for LC-PNCs. Micrographs of (g, h) LC-PNCs and (i, j) T-PNCs obtained by (g, i) scanning and (h, j) transmission electron microscopy.

Article Snippet: Ultraviolet–visible absorption spectra of the PNC solutions were obtained by using JASCO V-770.

Techniques: Purification, Synthesized, Transmission Assay, Electron Microscopy

Journal: ACS Nano

Article Title: Controlled Synthesis of Perovskite Nanocrystals at Room Temperature by Liquid Crystalline Templates

doi: 10.1021/acsnano.4c13217

Figure Lengend Snippet: Synthesis mechanism and optical properties of LC-PNCs. (a) Mean values of ξ (red circles, n ≥ 5) and L (blue squares, n ≥ 500) with respect to synthesis T . (b) PL spectra of LC-PNCs synthesized at T = 25 °C (black squares), 30 °C (red triangles), and 35 °C (blue circles) and (c) the corresponding λ peak with respect to synthesis T . PL spectra from the PNC solutions that are synthesized at T = 25 °C for (d) t s = 10 min and (e) 720 min. PL spectra of T-PNC solutions (black) are normalized by the maximum peak intensity of LC-PNC solutions (red). (f) λ peak for the LC-PNC (red stars) and T-PNC (black squares) solutions with respect to t s . PL spectra are measured with the PNC solutions (e) with and (d, f) without size purification processes.

Article Snippet: Ultraviolet–visible absorption spectra of the PNC solutions were obtained by using JASCO V-770.

Techniques: Synthesized, Purification

Journal: ACS Nano

Article Title: Controlled Synthesis of Perovskite Nanocrystals at Room Temperature by Liquid Crystalline Templates

doi: 10.1021/acsnano.4c13217

Figure Lengend Snippet: Compatibility of LC-LARP with other synthetic techniques. Controlled shape transformation of LC-PNCs using different concentrations of n -octylamine ( C OAm ): (a–d) transmission electron micrographs and (e) PL spectra from the LC-PNCs synthesized with C OAm = 0.12 (a, red line in e), 0.13 (b, yellow line in e), 0.15 (c, blue line in e), and 0.24 mmol (d, purple line in e). (f) Schematic illustration and (g) the corresponding fluorescence micrograph for LC-LARP applied into the microfluidic platform. The fluorescence signal (green in panel (g)) indicates the synthesis of LC-PNCs. In situ modification on PL spectra of the resulting LC-PNCs by precisely controlling their size via (h) the flow rate of the precursor solution (h and Figure S7a,b ) or (i) their shape via C OAm in the precursor solution. The inset of panel (i) is the photograph of the LC-PNC solutions excited by 365 nm light. All measurements are done with LC-PNCs without any size purification processes.

Article Snippet: Ultraviolet–visible absorption spectra of the PNC solutions were obtained by using JASCO V-770.

Techniques: Transformation Assay, Transmission Assay, Synthesized, Fluorescence, In Situ, Modification, Purification