Squarylium compound, light-emitting composition, and light-emitting film

Abstract

The present invention addresses the issue of providing: a novel squarylium compound that has high light-emission efficiency, in particular little reduction in light-emission efficiency in a solid membrane, and is capable of emitting a near-infrared light having excellent light resistance; and a light-emitting composition and a light-emitting film that contain said squarylium compound. This squarylium compound is characterized by having a structure indicated by general formula (1). ##STR00001##

Claims

1. A squarylium compound having a structure represented by Formula (1), ##STR00020## in Formula (1), a ring A and a ring B each respectively represent an aromatic hydrocarbon ring which may have a substituent; R.sup.1 represents an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group, or a halogen atom; R.sup.2 and R.sup.3 each respectively represent an alkyl group or a cycloalkyl group; R represents a substituent; R.sup.1 and R, or two Rs may be combined with each other to form a ring; R.sup.4 and R.sup.5 each respectively represent a hydroxy group or an amino group; and n1 and n2 each respectively represent an integer of 0 to 4.

2. The squarylium compound described in claim 1, wherein the compound having a structure represented by Formula (1) is a compound having a structure represented by Formula (2), ##STR00021## in Formula (2), a ring A and a ring B each respectively represent an aromatic hydrocarbon ring which may have a substituent; R.sup.1 and R.sup.6 each respectively represent an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group, or a halogen atom; R.sup.2 and R.sup.3 each respectively represent an alkyl group or a cycloalkyl group; R represents a substituent; R.sup.1 and R, R.sup.6 and R, or two Rs may be combined with each other to form a ring; R.sup.4 and R.sup.5 each respectively represent a hydroxy group or an amino group; and n1 and n2 each respectively represent an integer of 0 to 4.

3. The squarylium compound described in claim 1, wherein the compound having a structure represented by Formula (1) is a compound having a structure represented by Formula (3), ##STR00022## in Formula (3), a ring B represents an aromatic hydrocarbon ring which may have a substituent; R.sup.1 and R.sup.6 each respectively represent an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group, or a halogen atom; R.sup.2 and R.sup.3 each respectively represent an alkyl group or a cycloalkyl group; R represents a substituent; R.sup.1 and R, R.sup.6 and R, or two Rs may be combined with each other to form a ring; R.sup.5 represents a hydroxy group or an amino group; and n1 and n2 each respectively represent an integer of 0 to 4.

4. The squarylium compound described in claim 1, wherein the compound having a structure represented by Formula (1) is a compound having a structure represented by Formula (4), ##STR00023## in Formula (4), R.sup.1 and R.sup.6 each respectively represent an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group, or a halogen atom; R.sup.2 and R.sup.3 each respectively represent an alkyl group or a cycloalkyl group; R represents a substituent; R.sup.1 and R, R.sup.6 and R, or two Rs may be combined with each other to form a ring; and n1 and n2 each respectively represent an integer of 0 to 4.

5. A light-emitting composition containing the squarylium compound described in claim 1.

6. A light-emitting film containing the squarylium compound described in claim 1.

Description

EXAMPLES

(1) Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of “parts” or “%” is used, but unless otherwise specified, it indicates “parts by mass” or “% by mass”.

Example 1

(2) The compound used in a comparative example is shown below.

(3) ##STR00019##
<Measurement of Quantum Yield>

(4) With respect to squarylium compounds of the present invention D-1, D-3, D-5, D-6, D-7, D-10, D-12, D-17, D-21 and D-26, comparative compounds R-1 and R-4, the emission quantum yields in the solution and in the film were measured by the following methods, respectively.

(5) (1) Evaluation of Luminescence Quantum Yield in Solution

(6) The squarylium compound of the present invention or the comparative compound was dissolved in toluene so as to have a concentration of 10.sup.−6 M. The emission quantum yield of the obtained solution was measured using an absolute PL quantum yield measuring device (C11347 manufactured by Hamamatsu Photonics K.K.).

(7) (2) Evaluation of Emission Quantum Yield in the Film

(8) CBP (4,4′-N,N′-dicarbazolebiphenyl) and the squarylium compound of the present invention or the comparative compound were dissolved in chloroform so as to be contained at a ratio of 99.5% by mass and 0.5% by mass, respectively. The obtained solution was applied onto a quartz substrate by a spin coating method at 500 rpm for 30 seconds to form a thin film, and then dried at 50° C. for 30 minutes. The absolute PL quantum yield of the obtained thin film was measured using an absolute PL quantum yield measuring device (C11347 manufactured by Hamamatsu Photonics K.K.) and used as the emission quantum yield in the film. In Table I, the luminescence quantum yield of D-1 in the solution is shown as a relative value of 100.

(9) (Light Resistance)

(10) The film prepared under the same conditions as the measurement of emission quantum yield was covered with glass, and the decrease in absorption intensity at the maximum absorption wavelength from the sample after exposure to sunlight for 1 week with respect to the unexposed sample was calculated by the residual rate. The evaluation was made according to the following criteria. A spectrophotometer (U-3300 manufactured by Hitachi High-Tech Corporation) was used to measure the absorption intensity at the maximum absorption wavelength.
Residual rate (%)=(Maximum absorption wavelength intensity of exposed sample/Maximum absorption wavelength intensity of unexposed sample)×100

(11) AA: Residual rate is 90% or more

(12) BB: Residual rate is 80% or more and less than 90%

(13) CC: Residual rate is less than 80%

(14) Practically, a residual rate of 90% or more is preferable. The above evaluation results are shown in Table I.

(15) It should be noted that the exemplary compounds D-1, D-3, D-5, D-6, D-7, D-10, D-12, D-17, D-21 and D-26, which are the squarylium compounds of the present invention, were confirmed that they have a maximum emission wavelength in the near-infrared region of 700 to 850 nm in toluene. For the measurement, the above-mentioned Fluorescence Spectrophotometer F7000 manufactured by Hitachi High-Tech Corporation was used.

(16) TABLE-US-00001 TABLE I Emission quantum yield Measurement (Relative value) Light sample In solution In film resistance Remarks D-1 100 97 BB Present Invention D-3 103 105 BB Present Invention D-5 100 97 BB Present Invention D-6 114 111 AA Present Invention D-7 114 108 AA Present Invention D-10 121 119 AA Present Invention D-12 130 127 AA Present Invention D-17 122 124 AA Present Invention D-21 127 122 AA Present Invention D-26 124 125 AA Present Invention R-1 41 29 CC Comparative Example R-4 90 86 BB Comparative Example

(17) From Table I, it can be seen that the squarylium compound of the present invention has high luminous efficiency and excellent light resistance.

INDUSTRIAL APPLICABILITY

(18) The squarylium compound of the present invention emits near-infrared light having high luminous efficiency, particularly little decrease in luminous efficiency in a solid film, and excellent light resistance. It is possible to use it for infrared cameras, bioimaging, biosensing, and infrared communication.