Medical devices with photodetectors and related systems and methods

1. A medical device configured to couple to a body, the medical device comprising:

a substrate configured to couple to a user's skin;

a first illuminator configured to emit light at a first range of wavelengths;

a second illuminator configured to emit light at a second range of wavelengths, wherein the second range of wavelengths is different from the first range of wavelengths

a photodetector assembly comprising an array of quantum dot photodetectors, wherein the array of quantum dot photodetectors includes (i) a first quantum dot photodetector of a first size and configured to absorb light in the first range of wavelengths and (ii) a second quantum dot photodetector of a second size and configured to absorb light in the second range of wavelengths, wherein the first size is different from the second size; and

a controller electronically coupled to the photodetector assembly, the first illuminator, and the second illuminator and configured to:

deactivate the first quantum dot photodetector and the first illuminator when the second quantum dot photodetector and the second illuminator are activated; and

deactivate the second quantum dot photodetector and the second illuminator when the first quantum dot photodetector and the first illuminator are activated.

2. The device of claim 1 , further comprising at least one wire element positioned within the substrate, wherein the wire element is electrically coupled to the photodetector assembly, the first illuminator, and/or the second illuminator.

3. The device of claim 1 , further comprising a hydrogel layer extending across the substrate, wherein the photodetector assembly, the first illuminator, and the second illuminator are positioned within the hydrogel layer.

4. The device of claim 1 , wherein the controller is electronically coupled to the photodetector assembly, the first illuminator, and the second illuminator by one or more wire elements positioned within the substrate.

5. The device of claim 1 , wherein:

the first illuminator is configured to emit green light;

the second illuminator is configured to emit red light;

the first quantum dot photodetector is configured to absorb only green light; and

the second quantum dot photodetector is configured to absorb only red light.

6. The device of claim 5 , further comprising:

a third illuminator configured to emit infrared light; and

a third quantum dot photodetector configured to absorb only infrared light.

7. The device of claim 1 , wherein:

the first quantum dot photodetector includes a 5 nm diameter CdSe quantum dot;

the second quantum dot photodetector includes a 7 nm diameter CdSe quantum dot; and

the third quantum dot photodetector includes a 10 nm diameter PbS quantum dot.

8. The device of claim 1 , wherein the array of quantum dot photodetectors is arranged in a single layer honeycomb structure in which each quantum dot photodetector of the array of quantum dot photodetectors only boarders other quantum dot photodetectors of a different size.

9. The device of claim 1 , wherein:

the controller is configured to measure a first physiological parameter when the first illuminator is activated and the second illuminator is deactivated, wherein the controller is configured to use data from the photodetector assembly to calculate the first physiological parameter, and

the controller is configured to measure a second physiological parameter when the second illuminator is activated and the first illuminator is deactivated, wherein the controller is configured to use data from the photodetector assembly to calculate the second physiological parameter.

10. The device of claim 1 , wherein the photodetector assembly includes graphene and/or one or more titanium dioxide nanotube arrays.

11. The device of claim 1 , further comprising a body coupled to the substrate, wherein the photodetector assembly, the first illuminator, and the second illuminator are positioned within the body.

12. The device of claim 1 , wherein the substrate is a medical tape configured to couple to skin of a user.

13. The device of claim 1 , wherein the photodetector assembly is positioned between the first illuminator and the second illuminator.

14. The device of claim 1 , wherein the array of quantum dot photodetectors includes at least 1000 quantum dots.

15. The device of claim 1 , wherein the first quantum dot photodetector comprises a plurality of first quantum dots arranged in a row, and wherein the second quantum dot photodetector comprises a plurality of second quantum dots arranged in a row adjacent to the row of first quantum dots.

16. A medical device configured to couple to a body, the medical device comprising:

a flexible substrate configured to couple to a user's skin;

a photodetector assembly comprising an array of quantum dot photodetectors and one or more titanium dioxide nanotube arrays, wherein the array of quantum dot photodetectors includes a first quantum dot photodetector of a first size and a second quantum dot photodetector of a second size, wherein the first size is different from the second size;

a first illuminator configured to emit light at a first range of wavelengths;

a second illuminator configured to emit light at a second range of wavelengths, wherein the second range of wavelengths is different from the first range of wavelengths;

a controller; and

a wire element positioned on the flexible substrate and configured to electrically couple the first illuminator to the controller,

wherein the controller is configured to alternatingly activate and deactivate the first quantum dot photodetector, the second quantum dot photodetector, the first illuminator, and the second illuminator according to predetermined time intervals.

17. The device of claim 16 , wherein the array of quantum dot photodetectors includes a third quantum dot photodetector of a third size; and

wherein the first size is larger than the second size and the second size is larger than the third size.

18. The device of claim 17 , wherein the first quantum dot photodetector includes a 5 nm diameter CdSe quantum dot, the second quantum dot photodetector includes a 7 nm diameter CdSe quantum dot, and the third quantum dot photodetector includes a 10 nm PbS quantum dot.

19. The device of claim 17 , wherein the medical device is configured to measure at least one of: electrical activity of a user's heart, blood oxygen saturation, heart rate, respiration and/or cardiac output, blood pressure, and volumetric variations of blood circulation.

20. A method of measuring a physiological parameter using a medical device, the medical device comprising:

a flexible substrate configured to couple to a user's skin;

a photodetector assembly comprising an array of quantum dot photodetectors;

a first illuminator configured to emit light at a first range of wavelengths; and

a second illuminator configured to emit light at a second range of wavelengths, wherein the second range of wavelengths is different from the first range of wavelengths;

the method comprising:

coupling the medical device to a body;

activating a first quantum dot photodetector of the array of quantum dot photodetectors;

emitting light from the first illuminator towards the body;

receiving reflected light at the first quantum dot photodetector;

deactivating the first quantum dot photodetector;

activating a second quantum dot photodetector of the array of quantum dot photodetectors, wherein the second quantum dot photodetector is different from the first quantum dot photodetector and has a different size from the first quantum dot photodetector;

emitting light from the second illuminator towards the body; and

receiving reflected light at the second quantum dot photodetector.