The temperature ranges where a pure simple-cubic blue phase (BPII) emerges are quite narrow compared to the body-centered-cubic BP (BPI) such that the polymer stabilization of BPII is much more difficult. Hence, a polymer-stabilized BPII possessing a wide temperature range has been scarcely reported. Here, we fabricate a polymer-stabilized BPII over a temperature range of 50 °C including room temperature. The fabricated polymer-stabilized BPII is confirmed via polarized optical microscopy, Bragg reflection, and Kossel diagram observations. Furthermore, we demonstrate reflective BP liquid-crystal devices utilizing the reflectance-voltage performance as a potential application of the polymer-stabilized BPII. Our work demonstrates the possibility of practical application of the polymer-stabilized BPII to photonic crystals.

A well-aligned dye-doped blue phase II laser shows tunable emission wavelength and much lower emission threshold energy.

In this work, a systematic approach to controlling the orientation of a liquid-crystalline simple cubic blue phase (BPII) was carried out using a conventional surface rubbing treatment method. A more uniform lattice plane alignment in BPII was produced than in the liquid-crystalline-body-centered blue phase (BPI) using rubbed polyimide (PI) films on glass substrates. A single-color monodomain-like BPII was achieved regardless of the rubbed PI substrate pretilt angle. Additionally, singlecolor monodomain-like BPIIs with three elementary colors (red, green, and blue) were prepared, simply by changing the percentage of the chiral dopant.

We measured the helical twisting power (HTP) of nonchiral bent-core molecules doped in a chiral nematic liquid crystal, and found that HTP increases with the terminal chain length.