The photoluminescence (PL) of the GaAs substrate excited by the electroluminescence of the active layer is adopted to determine the junction temperature in AlGaInP∕GaAs light emitting diodes. Based on the Varshni equation for GaAs, the temperature measured by this approach is consistent with that obtained by the emission peak energy shift approach. As the PL signal is generated within the substrate, no calibration dependent on the device structure is necessary to determine the junction temperature of the device.

A novel metal‐organic framework (MOF) assembled by a semi‐rigid tricarboxylate, namely, 5‐(3,4‐dicarboxylphenoxy) nicotic acid (H3L) has been solvothermally synthesized: [Zn3(L)2(H2O)2] ⋅ 3H2O 1. Single‐crystal X‐ray diffraction analysis indicates that MOF 1 shows 2‐D layer with quadrangle channels along the a axis (ca. 7.0×8.3 Å2). The 2‐D layer self‐assembles into a final 3‐D supramolecular network via the interlayer π⋯π interactions. The photoluminescence investigations indicate that 1 can selectively and sensitively detect acetylacetone (acac) with high KSV value of 3.597×104 M−1 and low limit of detection (LOD) of 50.77 ppb. Further mechanism studies have shown that static photo‐competitive absorption, photoinduced electron transfer and H‐bonding interaction between chemosensor and the analyte may be the primary causes of the fluorescence quenching effect for acac.