A dual-emissive optical sensor based on the fluorescence intensity ratio (FIR) technique has been demonstrated to have significant advantages of high sensitivity and reliability. Here, we designed and successfully prepared a selfcalibrated optical luminescent thermometer of CsPbBr 3 quantum dot (QD) encapsulated lanthanide metal−organic frameworks (Eu-BTC), and their phase compositions and luminescence properties have been characterized. Different thermo-response luminescence behaviors originating from the photoluminescence of CsPbBr 3 QDs at 528 nm and the 5 D 0 − 7 F 2 emission of Eu 3+ at 618 nm were investigated in the temperature range of 20−100 °C, in which the dual-emissive temperature-dependent emissions can serve as a ratiometric thermometer for accurate temperature monitoring applications. Significantly, the as-obtained CsPbBr 3 @ Eu-BTC hybrid exhibited a high relative sensitivity (S r ) of 3.9% °C−1 at 20 °C and excellent temperature resolution of 0.004 °C in the measured temperature range, indicating its superiority as a ratiometric luminescent thermometer for temperature sensing. The related luminescent sensing mechanism of the CsPbBr 3 @Eu-BTC is also discussed, and this work provides an effective strategy for the rational design of a reliable and stable thermometer by integrating CsPbBr 3 QDs and a carrier of a luminescent lanthanide organic framework.

To develop highly reliable noncontact optical thermometer probe with excellent sensitivity and multi-mode temperature sensing behaviours is always a great challenge. Here, dual-emitting luminescent composites fabricated by europium-based metal organic...

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Controlled synthesis of rare-earth metal−organic frameworks (RE-MOFs) is of great significance to match their emerging multifunctional luminescence applications. Herein, we propose a green and general solventfree synthetic strategy for the adjustment of morphology and dimension of various RE-MOFs (RE = Eu, Tb, Er, Dy, Y, Tm) by using a tetraethylammonium bromide-assisted thermal-heating method. These selfassembled RE-MOF materials possess controllable morphologies and hierarchical structures while retaining the structural topology of MIL-78, proving that the strategy is a feasible and effective way in opening up largescale synthesis of RE-MOFs. It is further found that the tetraethylammonium could be carbonized into carbon dots and encapsulated in Eu/Tb-MIL-78 to enhance the fluorescence emission intensities significantly, making the hierarchical Eu/Tb-MIL-78 MOF materials good candidates for the latent fingerprints recognition application. This work provides a novel strategy for effectively controlling the morphology and dimension of RE-MOFs materials with enhanced photoluminescence and has great potential in their scaling-up syntheses and exploring the new luminescence applications.

Structural delamination of bulk layered metal–organic frameworks (MOFs) remains a great challenge, largely owing to a lack of general synthetic strategies. Here, we reported a simple solvent-free intercalation strategy for the delamination of rare-earth-based MOF (RE-MOF) with a topology structure of MIL-78 by tuning the chain length of quaternary ammonium salts. Four types of quaternary ammonium salts, involving tetraethylammonium bromide (TEAB), tetrapropylammonium bromide (TPAB), tetrabutylammonium bromide (TBAB), and hexadecyl trimethyl ammonium bromide (CTAB) were introduced to investigate their intercalation capabilities. It is evident in our case that the interruption/intercalation behavior of quaternary ammonium salts differs with their steric structures, and the chain-like CTAB can induce obvious delamination of MIL-78 crystals. Particularly, the CTAB-intercalated ultrathin Eu-based MIL-78 nanosheets exhibited unique selective photoelectrochemical sensing property toward trace amounts of Fe3+ ions in aqueous solution with a detection limit of 0.0899 μM at a signal-to-noise ratio of 3. These results demonstrated a green bottom-up strategy to obtain high-quality RE-MOF nanosheets for potential photocurrent response applications.