Photodiode arrays
A technique comprising: forming on a support film a first stack of layers defining an array of photodiodes; forming over the first stack of layers in situ on the support film a second stack of layers defining electrical circuitry by which the photoresponse of each photodiode is independently detectable via an array of conductors outside the array of photodiodes; wherein forming the first stack of layers comprises depositing an organic semiconductor material over a first electrode, and depositing a second electrode over the organic semiconductor material, wherein the electrical circuitry comprises transistors including photosensitive semiconductor channels, and the second electrode also functions to substantially block the incidence of light on the photosensitive semiconductor channels from the direction of the support film.
1. A method comprising:
forming on a support film a first stack of layers defining an array of photodiodes, wherein forming the first stack of layers comprises: i) depositing an organic semiconductor material over a first electrode, and ii) forming pixel electrodes over the organic semiconductor material, wherein forming the pixel electrodes comprises (a) depositing a continuous layer of organic conductor material over the organic semiconductor material, (b) depositing a continuous layer of reflective conductor material over the continuous layer of organic conductor material, (c) patterning the continuous layer of reflective conductor material to produce a reflective conductor material pattern, and (d) thereafter patterning the continuous layer of organic conductor material using the reflective conductor material pattern as a mask to produce an organic conductor material pattern having edges substantially aligned with edges of the reflective conductor pattern in the region of each pixel electrode; and
forming over the first stack of layers in situ on the support film a second stack of layers defining electrical circuitry by which the photoresponse of each photodiode is independently detectable via an array of conductors outside the array of photodiodes, wherein the electrical circuitry comprises transistors including photosensitive semiconductor channels, and the pixel electrodes also function to substantially block the incidence of light on the photosensitive semiconductor channels from the direction of the support film.
2. A method comprising:
forming on a support film a first stack of layers defining an array of photodiodes;
forming over the first stack of layers in situ on the support film a second stack of layers defining electrical circuitry by which the photoresponse of each photodiode is independently detectable via an array of conductors outside the array of photodiodes;
wherein forming the first stack of layers comprises coating an organic semiconductor material with a cathode material comprising at least one ionomer, without any plasma pre-treatment of the organic semiconductor material.
3. The method according to claim 2 , wherein the electrical circuitry comprises transistors including photosensitive semiconductor channels;
wherein the method comprises coating the cathode material with a reflective conductor material; and
wherein the cathode material and the reflective conductor material together substantially block the incidence of light on the photosensitive semiconductor channels from the direction of the support film.
4. The method according to claim 2 , wherein the cathode material comprises PEDOT:PSS.
5. The method according to claim 3 , wherein the reflective conductor material comprises an inorganic metal.