Materials, systems and methods for optoelectronic devices
A photodetector is described along with corresponding materials, systems, and methods. The photodetector comprises an integrated circuit and at least two optically sensitive layers. A first optically sensitive layer is over at least a portion of the integrated circuit, and a second optically sensitive layer is over the first optically sensitive layer. Each optically sensitive layer is interposed between two electrodes. The two electrodes include a respective first electrode and a respective second electrode. The integrated circuit selectively applies a bias to the electrodes and reads signals from the optically sensitive layers. The signal is related to the number of photons received by the respective optically sensitive layer.
1. A photodetector comprising:
a pixel region comprising an optically sensitive material;
pixel circuitry electrically coupled to the optically sensitive material, the pixel circuitry establishing a voltage over an integration period of time, wherein a signal is generated based on the voltage after the integration period of time, the signal having a noise level;
wherein a rate of the current flow through the optically sensitive material at relatively high light levels causes the voltage to remain above a minimum threshold as a result of a non-linear relationship between the voltage and intensity of the light absorbed by the optically sensitive material of the respective pixel region, wherein generating of the signal occurs when the voltage is greater than the minimum threshold;
a converter configured to convert the signal into digital pixel data, wherein the converter has an input range; and
at least one of the pixel circuitry and the optically sensitive layer providing a dynamic range more than at least twice the ratio of the input range of the converter divided by the noise level.
2. The photodetector of claim 1 , wherein the rate of current flow is non-linear relative to light intensity such that the optical sensitivity of the optically sensitive material at 1 lux is more than twice the optical sensitivity at 100 lux.
3. The photodetector of claim 1 , wherein the rate of current flow is non-linear relative to light intensity such that the dynamic range of the optically sensitive material is greater than dynamic range of an optical material in which the optical sensitivity at 1 lux is substantially the same as the optical sensitivity at 100 lux.
4. A photodetector comprising:
a pixel region comprising an optically sensitive material;
pixel circuitry in electrical communication with the optically sensitive material, the pixel circuitry establishing a voltage over an integration period of time;
read out circuitry configured to generate a signal based on the voltage after the integration period of time, wherein a rate of the current flow through the optically sensitive material at relatively high light levels causes the voltage to remain above a minimum threshold as a result of a non-linear relationship between the voltage and intensity of the light absorbed by the optically sensitive material, wherein generating of the signal occurs when the voltage is greater than the minimum threshold;
an analog-to-digital converter configured to convert the signal into digital pixel data, wherein the analog-to-digital converter has an input range and wherein the signal from the pixel circuitry has a noise level; and
wherein the pixel circuitry and the optically sensitive layer are configured to provide a dynamic range more than at least twice the ratio of the input range of the analog-to-digital converter divided by the noise level.
5. The photodetector of claim 4 , wherein the dynamic range is in a range of more than at least three times to approximately ten times the ratio of the input range divided by the noise level.
6. The photodetector of claim 4 , wherein the dynamic range is more than at least three times the ratio of the input range divided by the noise level.
7. The photodetector of claim 4 , wherein the dynamic range is more than at least five times the ratio of the input range divided by the noise level.
8. The photodetector of claim 4 , wherein the dynamic range is more than at least ten times the ratio of the input range divided by the noise level.
9. The photodetector of claim 4 , wherein a non-linear relationship exists between electrical characteristics of the optically sensitive material and intensity of light absorbed by the optically sensitive material, wherein a continuous function represents the non-linear relationship.
10. The photodetector of claim 9 , wherein the continuous function is a continuous polynomial function representing the non-linear relationship between photoconductive gain of the optically sensitive material and intensity of light absorbed by the optically sensitive material.
11. The photodetector of claim 9 , wherein a digital number corresponding to the digital pixel data has a linear relationship to the intensity.
12. The photodetector of claim 4 , wherein the rate of current flow is non-linear relative to light intensity such that the optical sensitivity of the optically sensitive material at 1 lux is more than twice the optical sensitivity at 100 lux.
13. The photodetector of claim 4 , wherein the rate of current flow is non-linear relative to light intensity such that the dynamic range of the optically sensitive material is greater than dynamic range of an optical material in which the optical sensitivity at 1 lux is substantially the same as the optical sensitivity at 100 lux.