Recently, circularly polarized luminescence (CPL)-active systems have become a very hot and interesting subject in chirality- and optics-related areas. The CPL-active systems are usually available by two approaches: covalently combining a luminescent centre to chiral motif or associating the guest of luminescent probe to a chiral host. However, all the chiral components in CPL materials were organic, although the luminescent components were alternatively organics or inorganics. Herein, the first totally inorganic CPL-active system by "luminescent guest-chiral host" strategy is proposed. Luminescent sub-10 nm lanthanide oxides (Eu O or Tb O ) nanoparticles (guests) were encapsulated into chiral non-helical SiO nanofibres (host) through calcination of chiral SiO hybrid nanofibres, trapping Eu (or Tb ). These lanthanide oxides display circular dichroism (CD) optical activity in the ultraviolet wavelength and CPL signals around at 615 nm for Eu and 545 nm for Tb . This work has implications for inorganic-based CPL-active systems by incorporation of various luminescent guests within chiral inorganic hosts.

What prompted you to investigate this topic/problem?Chirality is av ery attractive subject for chemists, physicists, and biologists. The chemist'sa pproach toward chiral materials often follows instinctive feeling rather than conscious reasoning. Although there are precise chiral rules in stereochemistry,t he rules could not dissuade us from looking for exceptional chirality,e ven if these exceptions are not obvious at present. The structures of silica frameworks are very complex, but tetrahedron-based stereochemistry can invoke chirality.O ur motivation is to find chiral features hidden within silica frameworks and to use this as ag eneral tool for the development of chiral materials. What was the inspiration for this cover design?When we were invited to submit the cover design, corresponding author Jin envisioned av iolently burning flame from which ap air of structured skeleton inside appear and emit beams of helical light. Jin asked professional graphic designer Mr.T akashi Ts ujino to conceptualize these motifs on ab alanced scene. The resulting cover picture shows ap air of enantiomeric sand grains encapsulating lanthanide nanoparticles that can resist high temperatures of up to 1000 8C, and which undergo left-handed and right-handed circularly polarized luminescence (CPL). In contrast, non-encapsulated lanthanide nanoparticles show no CPL emission.In one word,h ow would you describe your research?Beauty always comes from simple processes even if the target seems complex. Our research shown herein can be described as "self-sufficient". The formation of unique siliceous sands with special optical features comprises three "self" steps:s elf-organization, self-deposition, and self-encapsulation. Such sufficiency enables us to produce ceramic art:apair of sands hidden in at artrate "kilt" on the cluster-scale responds to external irradiation and exhibits brilliant circularly polarized luminescence.

Excellent ceramic materials emit colorful circularly polarized luminescence (CPL) in spite of their high‐temperature syntheses of up to 1000 °C. The process consists of three very simple self‐controlled steps: 1) self‐generation of a nanofibrous polymeric complex polyethylenemine/tartrate (PEI/tart) in water; 2) self‐deposition of silica around the complex to form chiral SiO2@PEI/tart hybrids; 3) self‐encapsulation of lanthanide ions into the hybrid to form a precursor of SiO2@PEI/tart/Ln3+. Final sintering of the precursors affords the circularly polarized light (CPL)‐active ceramics with chiral silica hosts and emissive lanthanide guests. More information can be found in the Communication by R.‐H. Jin et al. on page 6519.