A spirobifluorene compound and a perovskite solar cell including the spirobifluorene compound are disclosed. More particularly, a spirobifluorene compound which can be used as a hole transport material of a perovskite solar cell is disclosed. A perovskite solar cell including the spirobifluorene compound as a hole transport material is further disclosed.

A spirobifluorene compound and a perovskite solar cell including the spirobifluorene compound are disclosed. More particularly, a spirobifluorene compound which can be used as a hole transport material of a perovskite solar cell is disclosed. A perovskite solar cell including the spirobifluorene compound as a hole transport material is further disclosed.

The present invention relates to certain fluorenes, to the use of the compounds in an electronic device, and to an electronic device comprising at least one of these compounds. The present invention furthermore relates to a process for the preparation of the compounds and to a formulation and composition comprising one or more of the compounds.

The present invention relates to certain fluorenes, to the use of the compounds in an electronic device, and to an electronic device comprising at least one of these compounds. The present invention furthermore relates to a process for the preparation of the compounds and to a formulation and composition comprising one or more of the compounds.

A photosensitive layer of an electrophotographic photosensitive member is a single layer and contains a charge generating material, a hole transport material, a first electron transport material, a second electron transport material, and a binder resin. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units (1), (2), (3), and (4).

##STR00001##

A percentage of the number of repeats of the repeating unit (3) relative to the total of the number of repeats of the repeating units (1) and the number of repeats of the repeating unit (3) is greater than 0% and less than 20%. The first electron transport material includes a compound represented by formula (A15) or (A16).

##STR00002##

The second electron transport material includes a compound represented by formula (B10), (B11), (B12), (B13), or (B14)

##STR00003##

An object of the present invention is to provide a novel squarylium dye that can achieve an equivalent chromaticity value of even a colored resin composition having a low content of the squarylium dye as compared with a colored resin composition comprising a conventional squarylium dye. The present invention provides a compound represented by the formula (I) wherein R.sup.4 to R.sup.4 each independently represent a hydrogen atom or the like; R.sup.5 to R.sup.8 each independently represent a hydrogen atom or the like; R.sup.9 and R.sup.10 each independently represent a monovalent saturated hydrocarbon group having 1 to 20 carbon atoms or the like; R.sup.11 and R.sup.12 each independently represent a halogen atom or an alkyl halide group having 1 to 6 carbon atoms; and m1 and m2 each independently represent an integer of 1 to 5. ##STR00001##

An object of the present invention is to provide a novel squarylium dye that can achieve an equivalent chromaticity value of even a colored resin composition having a low content of the squarylium dye as compared with a colored resin composition comprising a conventional squarylium dye. The present invention provides a compound represented by the formula (I) wherein R.sup.4 to R.sup.4 each independently represent a hydrogen atom or the like; R.sup.5 to R.sup.8 each independently represent a hydrogen atom or the like; R.sup.9 and R.sup.10 each independently represent a monovalent saturated hydrocarbon group having 1 to 20 carbon atoms or the like; R.sup.11 and R.sup.12 each independently represent a halogen atom or an alkyl halide group having 1 to 6 carbon atoms; and m1 and m2 each independently represent an integer of 1 to 5. ##STR00001##

The triarylamine compound is represented by the following general formula (1), and the material, the optical element, and the optical apparatus each include a polymerized product (cured product) of the triarylamine compound. ##STR00001##
(In the general formula (1), R.sup.1 and R.sup.2 are each independently selected from a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, and a substituted or unsubstituted alkylene group having 1 to 8 carbon atoms, the alkylene group having a polymerizable functional group, and R.sup.3 to R.sup.12 are each independently selected from a hydrogen atom, a cyano group, a trifluoromethyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkylene group having a polymerizable functional group, and a polymerizable functional group, provided that at least one of R.sup.3 to R.sup.12 represents an electron-withdrawing group, and at least one of R.sup.1 to R.sup.12 has a polymerizable functional group.)

A method for producing a nitroso compound of the following formula (3), comprising reacting a compound of the following formula (1) with a compound of the following formula (2) by using a tertiary alcohol and a base. ##STR00001## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are each independently a hydrogen atom, a halogen atom, a (C1-C4) alkyl, or a (C1-C4) alkoxy.

A method for producing a nitroso compound of the following formula (3), comprising reacting a compound of the following formula (1) with a compound of the following formula (2) by using a tertiary alcohol and a base. ##STR00001## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are each independently a hydrogen atom, a halogen atom, a (C1-C4) alkyl, or a (C1-C4) alkoxy.