A compound represented by the structure of Formula (I), or a salt thereof suitable for use as a buffer in an electrochromic device is disclosed.

An optical film includes: a transparent substrate; and a colored layer laminated on at least one side of the transparent substrate, the colored layer containing a dye (A), the dye (A) containing a colorant having a wavelength of maximum absorption in the range of 470 nm to 530 nm, the colorant containing a dipyrromethene cobalt complex having a structure represented by formula (I), in which R.sup.1 to R.sup.7 are combined such that a free energy change between before and after the reaction, calculated by applying R.sup.1 to R.sup.7 in the formula (I) to a predetermined reaction formula (II) using a quantum chemical calculation program Gaussian 16 with a calculation method B3LYP and a basis function 6-31G (d,p) (however, a basis function LanL2DZ is assigned to elements having an atomic number greater than that of Kr in the periodic table), is 0.92 kcal/mol or greater.

Provided are compounds of Formula I

##STR00001##

that are useful as emitters in OLEDs.

The invention relates to electrochemical devices comprising complexes of cobalt comprising at least one ligand with a 5- or six membered, N-containing heteroring. The complex are useful as p- and n-dopants, as over of electrochemical devices, in particular in organic semiconductors. The complexes are further useful as over-discharge prevention and overvoltage protection agents.

The invention describes electronic devices comprising a metal complex compound having at least one tetradentate ligand having N and/or P donors, in particular a ligand having a PPPP, NNNN, PNNP or NPPN structure, and uses of a complex of this type in the electronic field and for the generation of light.

A light emitting device includes a first electrode, a hole transporting layer in contact with the first electrode, a second electrode, an electron transporting layer in contact with the second electrode; and an emissive layer between the hole transporting layer and the electron transporting layer. The emissive layer includes a metal-assisted delayed fluorescent (MADF) emitter, a fluorescent emitter, and a host, and the MADF emitter harvests electrogenerated excitons and transfers energy to the fluorescent emitter.

A printing material particle for a printing apparatus may include a colorant, a binder resin, and a metal-salen complex compound. The metal-salen complex compound may absorb ultra-violet (UV) light to emit visible light to be fluorescent.

A metallo-supramolecular polymer is formed by alternately linking metal cations and organic ligands through coordinate bonds, wherein a metallo-supramolecular polymer containing tris(terpyridine) compounds represented by a formula (B) and bis(terpyridine) compounds represented by a formula (L) as the organic ligands has high coloration efficiency.

A display panel and an electronic device are provided. The electronic device includes the display panel, the display panel includes a color filter layer, and the color filter layer includes a green photoresist. By adding a pigment A shown in a structural formula (I) to a color material of the green photoresist, the influence of illumination on the green photoresist can be reduced, and therefore, the transmittance of the green photoresist is improved.

The present invention relates to an electroluminescent device comprising an electron injection layer comprising a compound of formula (I) and a metal and a display device comprising the organic electroluminescent device.

##STR00001##