Size‐Distribution Control of Exfoliated Nanosheets Assisted by Machine Learning: Small‐Data‐Driven Materials Science Using Sparse Modeling (Adv. Theory Simul. 10/2021)

Nanosheet‐Based Uneven Thin Film Exhibiting Angle‐Independent Structural Color and Its Application to Detection of Biogenic Amines

“…The combination of host (niobate), guest (4‐(aminomethyl)benzonitrile, CN‐BA), and dispersion medium (water) was chosen based on the prediction results in our previous work to obtain polydispersed nanosheets. [ 26 ] Although the structural color was observed on the thin film based on the polydispersed nanosheets, [ 26 ] the angle independence and its mechanisms have not been fully studied in the previous work. The layered composite of niobate and CN‐BA was dispersed in purified water to induce exfoliation.…”

“…The surface‐modified nanosheets 2.63 ± 2.41 µm in lateral size and 13.1 ± 10.5 nm in thickness were obtained by the filtration of the unexfoliated bulky objects through sanitary cotton (Figure 2a and Figure S1, Supporting Information). [ 26 ] The filtered dispersion liquid was drop‐cast onto a cleaned silicon wafer under heating. The thin film was blue (Figure 2b), whereas the precursor layered material and colloidal liquid were white.…”

“…Niobate nanosheets were synthesized by the methods according to the previous report. [ 26 ] Briefly, 4‐(aminomethyl)benzonitrile hydrochloride (CN‐BA, TCI, 85.0%) was intercalated in potassium niobate. The layered (CN‐BA)‐niobate (30 mg) was dispersed in 12 cm 3 of purified water and stirred at 300 rpm and 60 °C for 5 days.…”

“…The prediction models for the yield, size, and size distribution were constructed through the extraction of the descriptors by a combination of machine learning and chemical insight on small experimental data. [ 23–28 ] These predictors contributed to the efficient exploration of appropriate experimental conditions, such as host–guest–medium combinations that yield the monodispersed and polydispersed nanosheets. [ 26 ] In the present work, surface‐modified nanosheets with polydispersed lateral sizes and thicknesses were used to prepare an uneven thin film exhibiting an angle‐independent structural color ( Figure ).…”

“…[ 23–28 ] These predictors contributed to the efficient exploration of appropriate experimental conditions, such as host–guest–medium combinations that yield the monodispersed and polydispersed nanosheets. [ 26 ] In the present work, surface‐modified nanosheets with polydispersed lateral sizes and thicknesses were used to prepare an uneven thin film exhibiting an angle‐independent structural color ( Figure ). The corresponding host–guest–medium combinations were selected based on the prediction model.…”