An organic photodiode is presented. The organic photodiode includes a first electrode; an organic absorber layer disposed on the first electrode; a second electrode disposed on the organic absorber layer; and a first charge blocking layer including a metal fluoride disposed between the organic absorber layer and one of the first electrode or the second electrode. The metal fluoride comprises lithium, sodium, potassium, rubidium, cesium, berrylium, magnesium, calcium, strontium, barium, iron, yttrium, ytterbium, or combinations thereof. The charge blocking layer is substantially free of an electrically conductive material, and the thickness of the charge blocking layer is greater than about 10 nanometers. A method of making an organic photodiode and an organic x-ray detector are also presented.