TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Solar Collector: The solar collector comprises the fluorescent dye (0.001-1 wt.%), based on the total weight of the sheet.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The base comprises sodium or potassium.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Preparation of the fluorescent dye (Ia) or (Ib) involves condensing a tetrachloroperylene dianhydride with an o-phenylene diamine to form an intermediate; and reacting the intermediate with a base and a phenol of formula (IX) in an aprotic polar solvent. The condensing step is performed at 80-200 degrees C, over a period of 3-12 hours in organic solvent. The reacting step is performed at 80-200 degrees C, over a period of 4-36 hours. Preferred Compound: In the compound (Ia) and (Ib), each phenoxy ring is substituted in only the para position with an R group; and the four R groups in the para position are the same. Preferred Components: The organic solvent is selected from propionic acid, acetic acid, imidazole, quinoline, isoquinoline, N-methylpyrrolidone, dimethylformamide, orhalogenated solvents. The aprotic polar solvent is selected from dimethylformamide, n-methylpyrrolidone, dimethyl sulfoxide, dimethylacetamide, or halogenated solvents.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The thermoplastic polymer is a polycarbonate polymer or polymethyl methacrylate. Preferred Definitions:    R=8-18C alkyl.    SPECIFIC COMPOUNDS - 4 Compounds are specifically claimed as the compound (I) comprises aromatic ether compound of formulae (II)-(V).    EXAMPLE - 1,6,7,12-Tetrachloroperylene-3,4,9,10-tetradicarboxydianhydride (2 g) and o-phenylenediamine (1.85 g) were placed into a flask, and propionic acid (30 ml) was added. The mixture was stirred at 140 degrees C for 6 hours, then cooled to 80-90 degrees C. After work-up a intermediate product (234 g) was obtained. The intermediate product (3 g), nonyl phenol (5.85 g) and potassium carbonate (3.65 g) were added to N-methylpyrrolidone (60 ml). The reaction mixture was stirred at 150 degrees C for 24 hours, then cooled to room temperature. The reaction mixture was treated with chilled 10 ml concentrated hydrochloric acid in an ice bath until evolution of gas ceased. After work-up aromatic ether compound of formula (II) or (III) (0.61 g) was obtained.