A semiconductor light emitting device includes a first cladding layer, a second cladding layer, and an active layer formed between the first and second cladding layers. The chelates contain either three acetates and one methylphosphonic arm or three acetates and one methylphosphonic arm enabling to link the chelate through P-alkyl within phosphoric acid derivative or through PO-alkyl within phosphonic derivative to any organic back-bone suited for targeting. The differential gloss is provided by coating a substrate with a UV-curable coating composition, subjecting a first region of the surface coating to polymerization under a first set of conditions, and subjecting a second region of the surface coating to polymerization under a second set of conditions. The direct travel times are subtracted from the total travel time to produce the actual travel time between the points on the surface.