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The low thermal conductivity and poor shape stability of phase change materials (PCMs) limit their application in the field of energy-saving buildings. Lauric-myristic acid (LA-MA)/modified expanded vermiculite (MEV) composites as form-stable phase change materials (FS-PCMs) were prepared in this study. To improve their heat transfer properties, expanded vermiculite (EV) was impregnated with sucrose, starch and glucose solutions and then carbonized at a high temperature to attain MEVs, which act as a matrix in the PCMs. LA-MA was adsorbed into the MEVs to obtain the LA-MA/MEV FS-PCMs. Scanning electron microscopy (SEM) shows that both EV and MEV have highly porous structures and can be used as PCMs carriers. The composite PCMs impregnated with starch obtain the best heat transfer properties in comparison with the other two samples. The melting temperature of the composite PCMs is 34.2 °C and the melting latent heat value is 141.9 J/g. Thermogravimetric analysis (TGA) shows that the composite PCMs present good thermal stability. Overall, LA-MA/MEV FS-PCMs are promising energy efficient materials that can be used as building materials. [ABSTRACT FROM AUTHOR]

A series of color-tunable warm white-emitting phosphors Ca 3 Y(AlO) 3 (BO 3) 4 :Dy3+,Eu3+ were synthesized and characterized for their crystal structure, luminescence properties, thermal stability, fluorescence decay and energy transfer mechanism. The results show that the optimal excitation wavelength and doping concentration of Ca 3 Y(AlO) 3 (BO 3) 4 :Dy3+ phosphor are 350 nm and 0.05 mol%, respectively, and its concentration quenching is mainly caused by the interaction between nearest neighbor ions. Under the excitation at 350 nm, the Ca 3 Y(AlO) 3 (BO 3) 4 :Dy3+,Eu3+ phosphor showed prominent emission peaks at 471 nm, 576 nm and 622 nm. The photoluminescence spectrum and lifetime decay curves confirmed the presence of Dy3+→Eu3+ energy transfer in Ca 3 Y(AlO) 3 (BO 3) 4. The phosphor of Ca 3 Y 0·85 (AlO) 3 (BO 3) 4 :0.05Dy3+,0.1Eu3+ exhibited remarkable thermal stability and could maintain 87.68% of the emission intensity at 150 °C. By adjusting the doping ratio of Dy3+ and Eu3+ ions, the CIE coordinates and the related color temperature of Ca 3 Y(AlO) 3 (BO 3) 4 :Dy3+,Eu3+ phosphors can be adjusted. The w-LED device packaged with Ca 3 Y 0·85 (AlO) 3 (BO 3) 4 :0.05Dy3+,0.1Eu3+ phosphor can emit warm-white light (Tc = 3284 K, Ra = 72.7). These results suggest that Ca 3 Y(AlO) 3 (BO 3) 4 :Dy3+,Eu3+ phosphor can provide a potential alternative for the warm w-LED market. [Display omitted] • Synthesis of Ca 3 Y(AlO) 3 (BO 3) 4 :Dy3+, Eu3+ phosphors was successful. • The energy transfer between Dy3+ and Eu3+ in Ca 3 Y(AlO) 3 (BO 3) 4 was studied. • Ca 3 Y(AlO) 3 (BO 3) 4 :Dy3+, Eu3+ co-doped phosphors display exceptional thermal stability. • The CCT and color coordinates of warm white Ca 3 Y(AlO) 3 (BO 3) 4 :Dy3+, Eu3+ phosphors can be modified. [ABSTRACT FROM AUTHOR]