Optical temperature sensing is a promising method to achieve the contactless temperature measurement and large-scale imaging. The current status of optical thermometry of rare-earth ions doped phosphors is reviewed in detail.

This work presents a new method to effectively improve the optical temperature behavior of Er³⁺ doped Y₂O₃ microtubes by co-doping of Tm³⁺ or Ho³⁺ ion and controlling excitation power. The influence of Tm³⁺ or Ho³⁺ ion on optical temperature behavior of Y₂O₃:Er³⁺ microtubes is investigated by analyzing the temperature and excitation power dependent emission spectra, thermal quenching ratios, fluorescence intensity ratios, and sensitivity. It is found that the thermal quenching of Y₂O₃:Er³⁺ microtubes is inhibited by co-doping with Tm³⁺ or Ho³⁺ ion, moreover the maximum sensitivity value based on the thermal coupled ⁴S_3/2/²H_11/2 levels is enhanced greatly and shifts to the high temperature range, while the maximum sensitivity based on ⁴F_9/2(1)/⁴F_9/2(2) levels shifts to the low temperature range and greatly increases. The sensitivity values are dependent on the excitation power, and reach two maximum values of 0.0529/K at 24 K and 0.0057/K at 457 K for the Y₂O₃:1%Er³⁺, 0.5%Ho³⁺ at 121 mW/mm² excitation power, which makes optical temperature measurement in wide temperature range possible. The mechanism of changing the sensitivity upon different excitation densities is discussed.

The helicene is constructed by twisted benzene or other aromatic rings, exhibiting a helical structure. Using first-principles calculations, we investigate the electronic transport of helicenes under stretching or compressing. Interestingly, a U-shaped curve of the current against d (the pitch of a helicene) is observed. Further analysis shows that, it is the result of the nonmonotonic change of HOMO-LUMO gap with d. The change of overlap between orbitals induced by conformational deformation is found to be the underlying mechanism. Moreover, the U-curve phenomenon is an intrinsic feature of the helicene molecules, being robust to the electrode materials or doping. This U-curve behavior is expected to be extended to helical graphene or other related structures, showing great application potential.

Two-probe systems of transition metal atom (X)-encapsulated B₄₀fullerene contacted with Au electrodes, where X = Fe, Mn, Ni, and Co.