NOVELTY - The organic photosensitive optoelectronic device (30) comprises an anode (312), an organic photosensitive layer formed on the anode, a hole blocking layer (315) formed on the organic photosensitive layer such that the organic photosensitive layer is sandwiched between the anode and the hole blocking layer, and a cathode (313) formed on the hole blocking layer such that the hole blocking layer is sandwiched between the cathode and the organic photosensitive layer. The organic photosensitive layer has an acceptor portion and a donor portion, which are mixed.    USE - The organic photosensitive optoelectronic device is useful in a light detection device (claimed), where the optoelectronic device is a LED and a solar cell.    ADVANTAGE - The organic photosensitive optoelectronic device efficiently suppresses dark current by effectively blocking injection of holes from the cathode to the photosensitive layer and provides options of metal electrodes of more stable materials thus enhancing the lifetime and sensitivity of the light detection device.    DETAILED DESCRIPTION - The organic photosensitive optoelectronic device (30) comprises an anode (312), an organic photosensitive layer formed on the anode, a hole blocking layer (315) formed on the organic photosensitive layer such that the organic photosensitive layer is sandwiched between the anode and the hole blocking layer, and a cathode (313) formed on the hole blocking layer such that the hole blocking layer is sandwiched between the cathode and the organic photosensitive layer. The organic photosensitive layer has an acceptor portion and a donor portion, which are mixed. A highest occupied molecular orbital (HOMO) of the hole blocking layer is 0.3 eV higher than that of a work function of the cathode or the donor portion such that injection of holes from the cathode to the organic photosensitive layer is blocked to suppress dark current. An electron blocking layer (317) is formed between the organic photosensitive layer and the anode. A lowest unoccupied molecular orbital (LUMO) of the electron blocking layer is 0.3 eV lower than that of the acceptor portion or the work function of the anode. The hole blocking layer has a porous surface structure or an irregular surface. An INDEPENDENT CLAIM is included for a light detection device.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic sectional view of an organic photosensitive optoelectronic device.    Organic photosensitive optoelectronic device (30)    Organic photosensitive layer (311)    Anode (312)    Cathode (313)    Hole blocking layer (315)    Electron blocking layer. (317)