Performance evaluation of phosphor-based luminescent bricks using different coating methods

This study investigates the luminescence and durability properties of SrAl2O4: Eu/Dy phosphor (SP) coated bricks incorporating different coating materials, such as glaze powders (Fx200 and TranspG) and epoxy resin. The luminescent brick specimens were differentiated by materials and methods used for coating, including only SP (S1), SP with low content of glaze powders (S2), SP with high content of glaze powder (S3), and SP with epoxy resin (S4). The performance of specimens was evaluated through surface brightness, spectral analysis, decay characteristics, UV-VIS diffuse absorbance spectral (DAS) analysis, solar light aging resistance, and freeze-thaw resistance. The results revealed that S1, S2, and S4 exhibit the highest surface brightness and radiate slowly for more than 45 s after exciting specimens for 2 min. The peak excitation spectra of S1, S2, S3, and S4 exist between 517.5 nm and 519.5 nm, representing the electron transition between 4d and 5f in Eu2+. The decay characteristics and UV-VIS DAS analysis revealed that all specimens can absorb incident light energy and emit it for a longer time, and the capability of absorbing light energy and afterglow duration of S1 and S4 outperformed that of S2 and S3. Moreover, S1 and S4 exhibit high resistance against solar light aging and freeze-thaw cycles. However, such bricks may lead to a cost increase of 38-75 % compared to conventional bricks, which can be offset by energy conservation. This study suggests that luminescent bricks can be used as a multi-functional building material and contribute towards sustainable development goals.