Since Tang et al.¹ introduced the 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) laser dye, a great number of scientists around the world have been extensively studying the chemistry and physics of the mentioned dye. The number of citations (ISI Web of Science) of the first paper where DCM was reported¹ has reached over 2700. Various synthetic modifications of DCM-type derivatives have been obtained and investigated, mostly for potential applications in OLEDs, as dopants in the electroluminescence layer² 3. ^{– 4} and in DCM:Alq3 (tris(8-hydroxyquinolinato) aluminum) solid-state laser systems as the light-amplification or gain medium.^1,5 6. ^{– 7} To maintain a high transparency and optical clarity of such systems, those are usually obtained by expensive and technologically complicated thermal evaporation in vacuum on the glass/indium tin oxide (ITO) substrates.^{6 – 7}

In this work we present simple preparation of original trityl group containing glassy luminescent 6-styryl substituted derivatives of 2-(2-tert-butyl-4H-pyran-4-ylidene)malononitrile (DWK-1TB), 2-(2-tert-butyl-4H-pyran-4-ylidene)-2- ethyl-2-cyanoacetate (KWK-1TB), 2-(2-tert-butyl-4H-pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK-1TB) and 5-(2-tert-butyl-4H-pyran-4-ylidene)pyrimidine-2,4,6(1H,3H,5H)-trione (JWK-1TB). Their optical properties have been investigated. The absorption maxima of synthesized glasses is in region from 425 nm to 515 nm and emission maxima is from 470 nm to 625 nm in solution of dichloromethane. But absorption maxima of their solid films is from 425 nm to 500 nm and emission maxima is in range from 570 nm to 710 nm. Incorporation of bulky trityloxy ethyl groups combining with existing tert-butyl groups results in thin solid films formation of synthesized glasses from volatile organic solvents (chloroform, dichloromethane) without them being doped in any polymer. This makes them perspective for potential applications in organic light-emitting diodes and organic lasers by simple luminescent layer composition with cheap wet-casting approaches. All glasses show good thermal stability with thermal decomposition temperatures from 264° to 318°C and glass transition values up to 158°C for DWK-1TB. These thermal properties of synthesized glasses could make them also useful for potential applications in other optical materials such as materials for nonlinear optics.

A series of 2,6-bis-styryl-4H-pyran-4-ylidene fragment containing glassy organic compounds with chemically stable bonding of amorphous phase promoting bulky triphenyl moieties through piperazine structural fragment (DWK-T dyes) in a form of 2-(5,5,5-triphenylpentyl)piperazin-1-yl)styryl)-substituent have been synthesized and investigated as the potential gain medium component for organic solid state laser applications. Physical properties of the dyes vary and are mostly depending from the other styryl-substituent attached to the 4H-pyran-4-ylidene backbone fragment in 6-position. Thermal stability of synthesized dyes is above 312°C with the glass transitions from 97°C to 109°C. Obtained neat spin-cast films based on these compounds exhibit photoluminescence with λmax in range from 672 nm to 695 nm, ASE λmax from 690 nm to 704 nm with ASE threshold values in range from 327 μJ/cm2 to 1091 μJ/cm2. Parameters are mostly influenced by the electron affinities of various 4-substituents in 6-styryl-fragment. The proposed synthetic approach could be useful for obtaining stable covalently bonded bulky triphenyl group containing glassy dyes while the synthetic design allows to acquire different non-symmetric 2,6-bis-styryl-4H-pyran-4-ylidene fragment containing compounds for infra-red light-emitting and light amplification systems.

The organic light-emitting diode (OLED) has promising applications in flat-panel displays and novel light sources. Thus far, OLED structures have mostly been made by thermal evaporation in vacuum. An alternative approach is to use small molecules that form amorphous (glassy) structures from solutions. Such compounds can be used in ink-jet printing technologies and result in reduced OLED prices. We present an original red fluorescent organic compo-und 2-(2-(4-(bis(2-(trityloxy)ethyl)amino)styryl)-6-methyl-4H-pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK1), and its derivative 2-(2,6-bis(4-(bis(2-(trityloxy)ethyl) amino)styryl)-4H-pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK2), where the methyl group is replaced with a 4-substituted-styryl group. This change could improve the formation of glassy structures. The thickness of the electroluminescent layer in the device is optimized to the higher power efficiency and obtains: ITO/PEDOT:PSS (40 nm)/ZWK1 (95 nm)/LiF (1 nm)/Al (100 nm), and ITO/PEDOT:PSS (40 nm)/ZWK2 (85 nm)/LiF (1 nm)/Al (100 nm). The maximum of electroluminescence (EL) spectra for the device with the ZWK1 compound is 667 nm, which corresponds to the CIE coordinates x = 0.65 and y = 0.34. The power and luminance efficiency at a luminance of 100 cd/m² is 0.63 lm/W and 1.78 cd/A, respectively. Adding an additional 4-substituted-styryl group to the ZWK1 molecule shifts the maximum of EL spectra to the red region (705 nm) and decreases the efficiencies by one order.

Organic solid-state lasers are highly promising devices known for their low-cost fabrication processes and compact sizes and the tunability of their emission spectrum. These lasers are in high demand across various industries including biomedicine, sensors, communications, spectroscopy, and military applications. A key requirement for light-emitting materials used in a light-amplifying medium is a low threshold value of the excitation energy of the amplified spontaneous emission (ASE). A newly synthesized non-symmetric red-light-emitting laser dye, Ethyl 2-(2-(4-(bis(2-(trityloxy)ethyl)amino)styryl)-6-tert butyl-4H-pyran-4-ylidene)-2-cyanoacetate (KTB), has shown great promise in meeting this requirement. KTB, with its attached bulky trityloxyethyl groups, has the ability to form amorphous thin films from a solution using a wet-casting method. Recent experiments have demonstrated that KTB exhibits a low ASE threshold value. This study focused on investigating the optical and amplified spontaneous emission properties of KTB in poly(N-vinylcarbazole) (PVK), polysulfone (PSU), and polystyrene (PS) matrices at various concentrations. The results showed that as the concentration of the dye increased, a redshift of the photoluminescence and ASE spectra occurred due to the solid-state solvation effect. The lowest ASE threshold value of 9 µJ/cm² was achieved with a 20 wt% concentration of KTB in a PVK matrix, making it one of the lowest excitation threshold energies reported to date.