JPH0424397B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a fluorescent collector.

Fluorescent collectors can be used, for example, in conjunction with solar cells to convert solar energy into other types of energy. Whether a fluorescent collector can be used economically is largely determined by the usefulness of the dye used therein as a light converter. Extreme demands are placed on the optical properties of this dye [Applied Physics (Appl.
Phys.), vol. 14, pp. 123-139 (1977)].

The present invention is formulated as a light converter. It relates to a novel fluorescent collector characterized in that it comprises a dye of the formula: R' represents _C1 - _C10 alkyl.

Compounds that can be used in the novel fluorescence collector are known [for example Ullmann, 3rd edition, pp. 722 et seq., German Patent Application No. 2451781;
2451782 and German Patent Application No. 2139688].

A system of the indicated dye in a matrix of suitable structure, i.e. a ratio of emissive to absorbing surfaces of 1:100.
~1:1000 optical system, our new fluorescence collector absorbs an incoming diffuse electromagnetic wave and radiates it with little loss into a medium that is optically denser than its surroundings. Most of the emitted light remains totally reflected in the medium.

Only that portion of the emitted light with a largely unabsorbed emission band can be used for the purposes of the present invention.

It is therefore advantageous to subject the dyes of formula () to a specific purification before use in a fluorescent collector. The invention therefore preferably provides a layer thickness of 10 cm in a solution containing from 0.5 to 2 mmol of the dye that can be used according to the invention, with a change in wavelength from 25 to 200 nm, preferably from 35 to 100 nm. Concerning a fluorescent collector characterized in that it contains a dye of the formula giving an increase in transmittance to 90%.

If convenient, the dye can be purified by several careful crystallizations. Separation by column chromatography on a solid carrier such as Al ₂ O ₃ or SiO ₂ is generally required.
A high degree of purity is achieved by partition chromatography.
It is obtained under particularly mild conditions, for example by steady state (O'Keefe) or by Craig countercurrent distribution.

The novel fluorescence collectors can be used, for example, in combination with solar cells for harnessing solar energy and with scintillators of known types [see, for example, J.B. Birks, "The Theory and Practice of Scintillation Counting". The
Theory and Practice of Scintillation
``Counting'', Pergamon Press (Pergamon
Press), London, 1964; J.Opt.Am., vol. 39, p. 912 (1949); Journal of Applied Physics (J.
Appl. Phys., vol. 40, p. 3544 (1969); and Nuclear Instruments and Methods.
87, pp. 111-123 (1970)].
It is furthermore suitable for use as an indicator with very low energy consumption in combination with electronic regulation. Furthermore, without electronic components, they are suitable for many display, notification and symbol purposes, for example passive display elements such as lights, display signals and traffic signals.

The fluorescent collectors of the present invention contain a dye dissolved in a liquid or a solid, and a wide variety of constructions are possible depending on the field of application of the fluorescent collector. Examples of suitable solid media used for collecting light, e.g. in combination with solar cells and in passive display elements, are homopolymers and copolymers of acrylic acid and its derivatives, or optical media such as polycarbonates. It is a plastic that can be used for many purposes and is transparent to light. In addition, the fluorescent collector may contain a dye dissolved in a liquid, such as an alcohol, ketone, halogenated hydrocarbon or ether. Examples of particularly suitable solvents are ethanol, propanol, methyl ethyl ketone, acetone, cyclohexanone,
Chloroform, perchlorethylene and glycol monomethyl ether.

The use of dyes of formula () according to the invention shows that, in addition to good quantum yields and high enhancement factors, they also have excellent fastness to light, thus making the use of the novel fluorescent collector economical. This is very advantageous because it guarantees that

It must be noted that it is surprising that dyes of formula () can be used advantageously in fluorescent collectors, since many dyes which are markedly fluorescent, such as Rhodamine G, cannot be used. Similarly, even the very high standards required for the optical properties of laser dyes are often insufficient to encourage the use of these dyes in fluorescent collectors.

Example 1 For purification, 2 g of di-i-butyl-3,9-perylene dicarboxylate with suitable color-effect properties are dissolved in chloroform. This solution is discharged into a column (8 cmφ) containing 1 kg of silica gel (Merck). The column is eluted with a mixture of chloroform and methanol in a ratio of 5:2. Discard the first dye component that gives the dirty blue-purple color. The main fraction of the eluate is evaporated and the residue is recrystallized from chloroform. melting point
Obtain bright orange-red crystals at 198°C.

The product thus obtained is incorporated into a commercially available methacrylate and the mixture is cast to give a sheet. At an excitation wavelength of 430 nm, the system gives a quantum yield of 82%. Transmission is 0 at 525nm
%, 90% at 535 nm.

If the above instructions are followed and diethyl 3,9-perylene dicarboxylate and dinonyl 3,9-perylene dicarboxylate are used instead of di-i-butyl ester, good fluorescence collectors are obtained.

Claims (1)

[Claims] 1 formula A fluorescent collector characterized in that it contains a dye in which R′ represents C ₁ -C ₁₀ alkyl. 2 When the dye is in a 0.5 to 2 mmol solution and the layer thickness is 10 cm,
A fluorescence collector according to claim 1, which provides an increase in transmittance from 0% to 90% with a wavelength change from 25 to 200 nm, preferably from 35 to 100 nm.