A material comprising an electron-accepting unit of formula (I): wherein Ar1 and Ar2 independently is a 5- or 6-membered aromatic or heteroaromatic ring or is absent; and each X is independently H or a substituent with the proviso that at least one X is an electron-withdrawing group and wherein X groups bound to adjacent carbon atoms may be linked to form an electron-withdrawing group. The material further comprises an electron-donating unit D comprising a fused or unfused furan or thiophene. The material may be a polymer comprising repeat units of formula (I). The material may be a non-polymeric compound. An organic photodetector may contain a bulk heterojunction layer containing an electron acceptor or an electron donor wherein at least one of the electron acceptor and electron donor contains a unit of formula (I).

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A material comprising an electron-accepting unit of formula (I): wherein Ar1 and Ar2 independently is a 5- or 6-membered aromatic or heteroaromatic ring or is absent; and each X is independently H or a substituent with the proviso that at least one X is an electron-withdrawing group and wherein X groups bound to adjacent carbon atoms may be linked to form an electron-withdrawing group. The material further comprises an electron-donating unit D comprising a fused or unfused furan or thiophene. The material may be a polymer comprising repeat units of formula (I). The material may be a non-polymeric compound. An organic photodetector may contain a bulk heterojunction layer containing an electron acceptor or an electron donor wherein at least one of the electron acceptor and electron donor contains a unit of formula (I).

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A composition comprising a first organic electron donor material having an absorption maximum greater than 900 nm; a second organic electron donor material having an absorption maximum at a shorter wavelength than the first organic electron donor material; and an organic electron acceptor material. The composition may be used in an organic photodetector.

An exemplary imaging device according to the present disclosure includes: an imaging region including a plurality of pixels; a peripheral region located outside of the imaging region; and a blockade region located between the imaging region and the peripheral region. Each of the plurality of pixels includes a photoelectric conversion layer, a pixel electrode to collect a charge generated in the photoelectric conversion layer, and a first doped region electrically connected to the pixel electrode. In the peripheral region, a circuit to drive the plurality of pixels is provided. The blockade region includes a second doped region of a first conductivity type located between the imaging region and the peripheral region and a plurality of first contact plugs connected to the second doped region.

An exemplary imaging device according to the present disclosure includes: an imaging region including a plurality of pixels; a peripheral region located outside of the imaging region; and a blockade region located between the imaging region and the peripheral region. Each of the plurality of pixels includes a photoelectric conversion layer, a pixel electrode to collect a charge generated in the photoelectric conversion layer, and a first doped region electrically connected to the pixel electrode. In the peripheral region, a circuit to drive the plurality of pixels is provided. The blockade region includes a second doped region of a first conductivity type located between the imaging region and the peripheral region and a plurality of first contact plugs connected to the second doped region.

An imaging element according to an embodiment of the present disclosure includes: a first electrode; a second electrode; an organic layer; a first semiconductor layer; and a second semiconductor layer. The second electrode is disposed to be opposed to the first electrode. The organic layer is provided between the first electrode and the second electrode. The organic layer includes at least a photoelectric conversion layer. The first semiconductor layer is provided between the second electrode and the organic layer. The first semiconductor layer includes at least one of a carbon-containing compound or an inorganic compound. The carbon-containing compound has a greater electron affinity than a work function of the first electrode. The inorganic compound has a greater work function than the work function of the first electrode. The second semiconductor layer is provided between the second electrode and the first semiconductor layer. The second semiconductor layer has an absolute value B of a difference between a HOMO (Highest Occupied Molecular Orbital) level and a Fermi level of the second electrode or has, near the Fermi level, an in-gap level having a state density of 1/10000 or more as compared with the HOMO level. The absolute value B is greater than or equal to an absolute value A of a difference between a first LUMO (Lowest Unoccupied Molecular Orbital) level and the Fermi level. The first LUMO level is calculated from an optical band gap.

The present invention further improves the measurement accuracy of the viscosity of an ink composition. An ink composition for forming a functional layer of an organic photoelectric conversion element, wherein an electron spin concentration per 1 L of volume of the ink composition is 250×10.sup.16 or less. The ink composition may be an ink composition containing a solvent and a p-type semiconductor material. The ink composition may be an ink composition in which the p-type semiconductor material contains a polymer compound having an electron spin concentration per 1 g of weight of 70×10.sup.16 or less. The ink composition may be an ink composition in which the solvent contains one or more types of organic solvents and the p-type semiconductor material contains a π-conjugated polymer compound containing a donor constitutional unit and an acceptor constitutional unit.

A photoelectric conversion device includes a first electrode, a photoelectric conversion layer, and a second electrode in sequence. The photoelectric conversion device includes a sealing member on a non-facing surface side of one electrode selected from the first electrode and the second electrode, the non-facing surface side not facing the photoelectric conversion layer. The sealing member includes an insulating layer, a metal layer, and a base in sequence from the one electrode. In an end of the sealing member in a surface direction, a length of the insulating layer in the surface direction is equal to or longer than a length of the metal layer in the surface direction, and the length of the metal layer in the surface direction is longer than a length of the base in the surface direction by 0.1 μm or more.

An organic photoelectric conversion device and an image sensor, the organic photoelectric conversion device including an upper electrode; a lower electrode; and an active layer between the upper electrode and the lower electrode, wherein the active layer includes bis-(4-dimethylaminodithiobenzyl)-Ni(II) (BDN) and [6,6]-Phenyl-C71-butyric acid methyl ester (PC70BM).

A composition comprising an electron-donating polymer and an electron acceptor wherein the electron-donating polymer comprises a benzo[1,2-b:4,5-b′]dithiophene repeat unit and wherein a film of the electron-accepting material has a peak absorption wavelength greater than 1000 nm. The composition may be used as a photosensitive layer of an organic photodetector.