TEMPERATURE AND TEMPERATURE DISTRIBUTION SENSING WITH HIGH RESOLUTION IN MICROSCOPIC ELECTRONIC DEVICES AND BIOLOGICAL OBJECTS

• US 20100008394A1
• Filed: 12/12/2007
• Published: 01/14/2010
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: Yasuda, Akio, Nelles, Gabriele, Miteva, Tzenka
• Granted Patent: US 8,434,939 B2
• Time in Patent Office: Days
• US Class Current: 374/1
• CPC Class Codes: G01K 11/20 using thermoluminescent materials G01K11/32 takes precedence
• CPC Class Codes: G01K 2211/00 Thermometers based on nanotechnology
• CPC Class Codes: G01K 2213/00 Temperature mapping
• CPC Class Codes: G02B 21/0076 arrangements using fluorescence or luminescence

Abstract

The present invention relates to a method of measuring a temperature and/or temperature distribution at a resolution <1 &mgr; m in an object and to a device for performing such method, more particularly to a microscope for performing such method. The method comprises applying a molecular thermometer embedded in a matrix layer on an object, photoexciting the said molecular thermometer with a light source of said microscope and measuring emission of radiation from said molecular thermometer with two photodetectors of said microscope. A first intensity at a first wavelength is measured by said first detector, a second intensity at a second wavelength is measured by said second.detector, and a ratio of said intensities is calculated and used to determine a temperature with a calibrated curve. Said microscope is a confocal microscope or a stimulated emission depletion (STED) microscope.

Claims

1. A method of measuring a temperature and/or temperature distribution at a resolution

<

1 μ

m in an object, such as an electronic device or a biological object, said method comprising the steps;

a) providing an object,

b) applying a thermometer layer on said object or on a part of the surface of said object, where a temperature and/or temperature distribution is to be measured, said thermometer layer comprising a matrix and a molecular thermometer having temperature dependent emission characteristics, said molecular thermometer being embedded in said matrix, said thermometer layer having a thickness <

40 nm, preferably in the range of from 10 nm to 40 nm,

c) providing a microscope having a light source, a first detector, a second detector, and a microscopy stage for receiving and scanning a sample to be examined,

d) placing said object on said microscopy stage and using said light source to photoexcite said molecular thermometer,

e) measuring emission of radiation from said photoexcited molecular thermometer by measuring a luminescence intensity ratio using said first and said second detector, wherein said luminescent intensity ratio is the ratio of luminescent intensity at a first and second wave-length, wherein said first and said second detector are used to measure a luminescence intensity at said first and second wavelength, respectively,

f) determining a temperature and/or temperature distribution based on said measured luminescence intensity ratio.

2. The method according to claim 1, wherein said microscope is a confocal microscope or a stimulated emission depletion (STED) microscope.

3. The method according to claim 1, wherein said molecular thermometer is selected from the group comprising metallo-porphyrins, other molecules having an inter-system crossing occur upon photoexcitation for >

1% of the excited singlet state(s), preferably >

50% of the excited singlet state(s), more preferably >

90% of the excited singlet state(s) (e.g. Br-containing molecules), and metal-organic molecules having e.g. Ir, Pt, Ru, or Pd or others like Zn, Fe, Au, Ag, etc. in their structure and having an inter-system crossing occur upon photoexcitation for >

1% of the excited singlet state(s), preferably >

50% of the excited singlet state(s), and more preferably >

90% of the excited singlet state(s).

4. The method according to claim 3, wherein said molecular thermometer is a metallo-porphyrin, preferably selected from zinc octaethyl porphyrin (ZnOEP), palladium octaethyl porphyrin (PdOEP), and platinum octaethyl porphyrin (PtOEP).

5. The method according to claim 1, wherein said molecular thermometer is present in said thermometer layer at concentrations in the range of from 0.001 to 5 wt. %, preferably from 0.01 to 3 wt. %, referring to the total weight of said matrix.

6. The method according to claim 1, wherein said matrix is optically transparent.

7. The method according to claim 1, wherein said matrix is inert.

8. The method according to claim 1, wherein said matrix is optically transparent and inert.

9. The method according claim 8, wherein said optically transparent and inert matrix is a polymeric matrix.

10. The method according to claims 9, wherein said polymeric matrix is made of a material selected from polystyrene, polymethylmethacrylate, polycarbonate, polysilicone, such as poly(dimethylsiloxane) (PDMS), polyolefine, e.g. polyethylene, polypropylene.

11. The method according to claim 1, wherein said matrix contains inorganic oxide or nitride.

12. The method according to claim 9, wherein said matrix contains inorganic oxide or nitride.

13. The method according to claim 1, wherein the applying b) is performed by a method selected from spin-coating, dip-coating, drop casting, doctor blading, Langmuir-Blodgett techniques, spraying, thermal evaporation, molecular beam deposition, lamination and adhering, e.g. gluing.

14. The method according to claim 1, wherein said thermometer layer is a multilayer structure and comprises at least two sublayers, wherein each sublayer, preferably, has different concentrations of said molecular thermometer.

15. The method according to claim 1, wherein no molecular heater layer is applied on said object to determine a temperature and/or temperature distribution in said object.

16. The method according to claim 1, wherein, in the placing d), said photo-excitation is performed by continuous excitation or pulsed excitation.

17. The method according to claim 16, wherein said photoexcitation occurs in the wavelength range from 400-600 nm.

18. The method according to claim 1, further comprising a calibration:

performing a calibration of said thermometer layer when applied to a substrate by

photoexciting said thermometer layers

measuring a luminescence intensity ratio from said thermometer layer at least two different temperatures,

measuring said at least two different temperatures using an external means for measuring said temperatures, and

correlating each measured luminescence ratio with its corresponding temperature,

wherein said calibration step is performed prior to the placing d) of photoexciting said molecular thermometer.

19. The method according to claim 18, wherein said calibration step is performed independently of any of the a)-f).

20. The method according to claim 1, wherein said luminescence intensity ratio is the ratio of a fluorescence intensity at said first wavelength, preferably including a delayed fluorescence intensity, such as e.g. delayed fluorescence that follows a triplet-triplet annihilation process, to a phosphorescence intensity at said second wavelength.

21. The method according to any claim 1, wherein said luminescence intensity ratio is the ratio of a fluorescence intensity of a singlet state of said molecular thermometer, optionally including a delayed fluorescence that follows a triplet-triplet annihilation process, at said first wavelength, to a phosphorescence intensity from an excited triplet state of said molecular thermometer at said second wavelength (I_singlet/I_triplet).

22. The method according to claim 1, wherein said molecular thermometer is PdOEP and said luminescence intensity ratio is I_549nm/I_662nm.

23. The method according to claim 1, wherein a resolution achieved is <

500 nm, preferably <

300 nm, more preferably <

200 nm, even more preferably <

100 nm in a plane perpendicular to the light beam of said microscope, and <

500 nm, preferably <

50 nm, more preferably <

20 nm and most preferably approximately 10 nm in a direction along the light beam of said microscope.

24. A microscope for performing the method according to claim 1, comprising:

a light source, such as a laser, a laser diode, a light emitting diode,

a first detector and a second detector for measuring a luminescence intensity ratio, said luminescence originating from a molecular thermometer layer

a microscopy stage for receiving and scanning a sample to be examined

an object placed on said microscopy stage and having a thermometer layer applied thereon, said thermometer layer thus giving rise to luminescence when photoexcited by a light beam from said light source.

25. The microscope according to claim 24, which is a confocal microscope or a stimulated emission depletion microscope (STED).