An organometallic compound represented by Formula 1:

M(L.sub.1).sub.n1(L.sub.2).sub.n2  Formula 1

In Formula 1, M is a transition metal; L.sub.1 is a ligand represented by Formula 2 as disclosed herein; L.sub.2 is a monodentate ligand, a bidentate ligand, a tridentate ligand, or a tetradentate ligand; n1 is 1, 2, or 3, wherein, when n1 is 2 or greater, two or more ligands L.sub.1 are identical to or different from each other; n2 is 0, 1, 2, 3, or 4, wherein, when n2 is 2 or greater, two or more ligands L.sub.2 are identical to or different from each other; and L.sub.1 and L.sub.2 are different from each other.

A photoelectric conversion element including: a first electrode; an electron-transporting layer; a hole-transporting layer; and a second electrode. The electron-transporting layer, the hole-transporting layer, and the second electrode are on or above the first electrode. The second electrode includes a charge-collecting layer. The charge-collecting layer includes a conductive nanowire and a conductive polymer that covers at least part of the conductive nanowire and is stacked on the hole-transporting layer.

Methods for preparation of surfactant-free ultra-small spinel ternary metal oxide nanoparticles are provided. A method comprises dissolving first and second metal salts in deionized water in a specific mole ratio to form a solution comprising two different metal ions, applying a coprecipitation method and adding an alkaline solution to the solution to form a colloidal suspension, wherein a colloid of the colloidal suspension is a metal hydroxide, adjusting the amount and the addition rate of the alkaline solution to form a specific structure of metal hydroxide precipitate; washing and drying the metal hydroxide to form a structured metal hydroxide powder, and applying a calcination method to the structured metal hydroxide powder to form a surfactant-free spinel-type (AB.sub.2O.sub.4) ternary metal oxide, wherein A and B each respectively comprise a metal element.

A ferroelectric enhanced solar cell, including a conductive substrate, and a hole blocking layer, a mesoporous nanocrystalline layer, a mesoporous spacer layer and a mesoporous back electrode sequentially deposited in that order on the conductive substrate. The mesopores of at least one of the mesoporous nanocrystalline layer, the mesoporous spacer layer and the mesoporous back electrode are filled with a photoactive material. At least one of the hole blocking layer, the mesoporous nanocrystalline layer and the mesoporous spacer layer includes a ferroelectric material or a ferroelectric nanocomposite.

A method for making a polymer solar cell includes placing a carbon nanotube array into a polymer solution. The carbon nanotube array includes a plurality of carbon nanotubes. Each carbon nanotube includes a first end and a second end opposite to the first end. The polymer solution is cured to form a polymer layer including a first polymer surface and a second polymer surface opposite to the first polymer surface. The first end is exposed from the polymer layer, and the second end is embedded in the polymer layer. An insulating layer is formed on the first polymer surface. A cathode electrode is formed on a surface of the insulating layer away from the polymer layer, and the first end passes through the insulating layer and is in direct contact with the cathode electrode. An anode electrode is formed on the second polymer surface.

A photoelectric conversion element including: a first electrode; a hole blocking layer; a photoelectric conversion layer; a second electrode; a third electrode; a photoelectric conversion part in which the first electrode, the hole blocking layer, the photoelectric conversion layer, and the second electrode are stacked; an electrode contact part in which the second electrode is in contact with the third electrode; and a division part dividing the photoelectric conversion part and the electrode contact part, wherein an area (S1) where the second electrode is in contact with the third electrode in the electrode contact part and an area (S2) of the photoelectric conversion part satisfy expression (1) below: 1.0×10.sup.−5≤100×(S1/S2) . . . expression (1).

An imaging device includes a first electrode, a second electrode, a photoelectric conversion layer that is arranged between the first electrode and the second electrode, and an electron blocking layer that suppresses movement of electrons from the first electrode to the photoelectric conversion layer. The electron blocking layer contains carbon and an oxide of chromium and is arranged between the first electrode and the photoelectric conversion layer.

Photoelectric conversion element including: substrate; first electrode; hole-blocking layer; photoelectric conversion layer; and second electrode, the photoelectric conversion layer including electron-transporting layer and hole-transporting layer, wherein in photoelectric conversion element edge part in direction orthogonal to stacking direction of the substrate, first electrode, hole-blocking layer, photoelectric conversion layer, and second electrode, electron-transporting layer outermost end is positioned inside than first electrode outermost end, hole-transporting layer outermost end is positioned outside than second electrode outermost end, and the second electrode outermost end is positioned inside than the electron-transporting layer outermost end, and height of edge part including the first electrode outermost end in the stacking direction is smaller than total of average thicknesses of first electrode, hole-blocking layer, and electron-transporting layer, where the height is distance between substrate surface at first electrode side and portion of first electrode closest to second electrode side in the photoelectric conversion element edge part.

A photoelectric conversion element including: a first electrode; a photoelectric conversion layer; and a second electrode, wherein the photoelectric conversion layer includes an electron-transporting layer and a hole-transporting layer, the electron-transporting layer includes a lithium ion, the hole-transporting layer includes an organic hole-transporting material and a lithium salt, and lithium included in the electron-transporting layer is more than lithium included in the hole-transporting layer.

Provided are a condensed cyclic compound represented by Formula 1 and an organic light-emitting device including the same:

##STR00001##

wherein, in Formula 1, X.sub.1, A.sub.1, L.sub.11, a11, Ar.sub.11, Ar.sub.12, b11, R.sub.11, R.sub.12, c11, and c12 are the same as defined in the specification.