The phase transition temperature (e.g., that of orthorhombic‐tetragonal TO‐T) of relaxor ferroelectrics are commonly obtained through electrical method (i.e., temperature dependence of dielectric constant), and the samples need to be coated with metal electrode and tested by a sophisticated impedance analyzer. This contact measuring method is inefficient, inconvenient and easy to damage the sample surface, inapplicable to transparent ferroelectrics. Here, we successfully fabricated Bi/Sm co‐doped K0.5Na0.5NbO3 transparent ceramics with photoluminescent behavior and relaxor‐like ferroelectricity, which simultaneously realized TO‐T monitoring and temperature sensing via fluorescence intensity ratio (FIR) technology. This simple, rapid, noncontact and nondestructive optical way displays small TO‐T deviation (merely 0.78%) compared to the electrical method. And the temperature‐dependent optical characteristics and coercive electric field all present abrupt changes, whose abnormal temperature regions are in accordance with that around TO‐T. In addition, the maximum absolute sensitivity and relative sensitivity of the ceramics reach 0.0072 K−1 (at 533 K) and 0.0111 K−1 (at 453 K), respectively, exhibiting superior optical temperature sensing performance. The tactical use of FIR technology is of great significance for widening the applications of luminescent‐ferroelectric transparent ceramics.

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Glucose sensing based on graphene conductance is investigated by the probe station and COMSOL Multiphysics. The current–voltage (I–V) results from the probe station show that there is a negative linear relationship between graphene conductance and glucose concentration. Using this relationship as the standard curve, the concentration of glucose on graphene can be obtained by measuring the conductance of graphene. The electrical behaviors of different glucose molecules on graphene simulated by COMSOL Multiphysics Toolbox indicate a scattering effect of glucose molecules on current and a more rapidly linear potential drop in the glucose region calculated from the equipotential line distribution, which is consistent with the experimental results. These results provide a new research perspective and method for the sensing of glucose and other biological substances.

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