Method and device for measuring unoccupied states of solid

Patent metadata

Field	Value
Publication number	US-9664564-B2
Application number	US-201314381742-A
Country	US
Kind code	B2
Filing date	Feb 26, 2013
Priority date	Feb 28, 2012
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

Intensity of near-ultraviolet light or visible light of 180 to 700 nm emitted from a solid sample, such as an organic semiconductor, irradiated with an electron beam is measured, while kinetic energy (accelerating energy) of the electron beam is changed in a range of 0 to 5 eV so as to obtain a spectrum. Peaks are detected from the spectrum, and the energy thereof is defined as unoccupied-states energy of the sample. The onset energy of the first peak represents electronic affinity energy (electron affinity) of the sample. Since the energy of the electron beam irradiated onto the sample is 5 eV or less, almost no damage is exerted on the sample even when the sample is an organic semiconductor.

First claim

The invention claimed is:

1. A method for measuring unoccupied states of an organic sample, comprising:
a) a step of generating an electron beam;
b) a step of generating an electric potential difference between an electron beam generator and the organic sample by applying a bias voltage to the electron beam generator and/or the organic sample, and irradiating the organic sample with the electron beam whose incident energy with reference to a potential of the organic sample is changed within a range of 0 to 5 eV, the organic sample being degradable above 5 eV;
c) a step of measuring intensity of light of a predetermined wavelength within a range of 180 to 700 nm included in electromagnetic waves emitted from the organic sample; and
d) a step of determining unoccupied-states energy of the organic sample based on a spectrum created by the intensity of light with respect to the kinetic energy of the electron beam.

2. The method for measuring unoccupied states of an organic sample according to claim 1 , wherein
in the step of measuring intensity of light, a bandpass filter having a transmission center wavelength of 180 to 700 nm is used.

3. The method for measuring unoccupied states of an organic sample according to claim 1 , wherein
in the step of measuring intensity of light, a spectroscope and an exit slit that perform wavelength scanning in a range of 180 to 700 nm are used.

4. A method for measuring unoccupied states of an organic sample, comprising:
a) a step of generating an electron beam;
b) a step of generating an electric potential difference between an electron beam generator and the organic sample by applying a bias voltage to the electron beam generator and/or the organic sample, and irradiating the organic sample with the electron beam whose incident energy with reference to a potential of the organic sample is accelerated with a predetermined energy within a range of 0 to 5 eV, the organic sample being degradable above 5 eV;
c) a step of spectrally separating light within a range of 180 to 700 nm included in electromagnetic waves emitted from the organic sample, and measuring intensity of each wavelength to generate a spectrum; and
d) a step of determining unoccupied-states energy of the organic sample based on the spectrum.

5. The method for measuring unoccupied states of an organic sample according to claim 4 , wherein
in the step of generating a spectrum, a spectroscope, an exit slit, and a photon detector are used, and an angular position of the spectroscope is changed to change wavelengths of light that passes through the exit slit so as to generate a spectrum.

6. The method for measuring unoccupied states of an organic sample according to claim 4 , wherein
in the step of generating a spectrum, light from the organic sample is spectrally separated with the spectroscope, and spectrally separated light is measured per wavelength with a linear sensor.

7. A device for measuring unoccupied states of an organic sample, comprising:
a) an electron beam generator;
b) an electron beam drive unit for generating an electric potential difference between the electron beam generator and the organic sample by applying a bias voltage to the electron beam generator and/or the organic sample, and irradiating the organic sample with the electron beam whose incident energy with reference to a potential of the organic sample is changed within a range of 1 to 5 eV, the organic sample being degradable above 5 eV;
c) a light intensity measuring unit for measuring intensity of light of a predetermined wavelength within a range of 180 to 700 nm included in electromagnetic waves emitted from the organic sample; and
d) an unoccupied states determiner for determining unoccupied-states energy of the organic sample based on a spectrum created by the intensity of light with respect to the kinetic energy of the electron beam.

8. The device for measuring unoccupied states of an organic sample according to claim 7 , wherein
the light intensity measuring unit has a bandpass filter having a transmission center wavelength of 180 to 700 nm and a photon detector that measures intensity of light passing the bandpass filter.

9. The device for measuring unoccupied states of an organic sample according to claim 7 , wherein
the light intensity measuring unit has a spectroscope and an exit slit that perform wavelength scanning in a range of 180 to 700 nm.

10. A device for measuring unoccupied states of an organic sample, comprising:
a) an electron beam generator;
b) an electron beam drive unit for generating an electric potential difference between the electron beam generator and the organic sample by applying a bias voltage to the electron beam generator and/or the organic sample, and irradiating the organic sample with the electron beam whose incident energy with reference to a potential of the organic sample is accelerated with a predetermined energy within a range of 0 to 5 eV, the organic sample being degradable above 5 eV;
c) a spectrum generator for generating a spectrum by spectrally separating light within a range of 180 to 700 nm included in electromagnetic waves emitted from the organic sample and measuring intensity of the light as a function of wavelength; and
d) an unoccupied states determiner for determining unoccupied-states energy of the organic sample based on the spectrum.

11. The device for measuring unoccupied states of an organic sample according to claim 10 , wherein
the spectrum generator includes a spectroscope, a spectroscope drive mechanism that changes an angular position of the spectroscope, an exit slit, and a photon detector.

12. The device for measuring unoccupied states of an organic sample according to claim 10 , wherein
the spectrum generator includes a spectroscope and a linear sensor.

13. A method for measuring unoccupied states of an organic sample, comprising:
a) a step of generating an electron beam;
b) a step of irradiating the organic sample with the electron beam whose incident energy with reference to a potential of the organic sample is changed within a range of 0 to 5 eV, the organic sample being degradable above 5 eV;
c) a step of measuring intensity of light of a predetermined wavelength within a range of 180 to 700 nm included in electromagnetic waves emitted from the organic sample, in which the electromagnetic waves are collected by using a lens; and
d) a step of determining unoccupied-states energy of the organic sample based on a spectrum created by the intensity of light with respect to the kinetic energy of the electron beam.

14. The method for measuring unoccupied states of an organic sample according to claim 13 , wherein
in the step of measuring intensity of light, a bandpass filter having a transmission center wavelength of 180 to 700 nm is used.

15. The method for measuring unoccupied states of an organic sample according to claim 13 , wherein
in the step of measuring intensity of light, a spectroscope and an exit slit that perform wavelength scanning in a range of 180 to 700 nm are used.

16. A method for measuring unoccupied states of an organic sample, comprising:
a) a step of generating an electron beam;
b) a step of irradiating the organic sample with the electron beam whose incident energy with reference to a potential of the organic sample is accelerated with a predetermined energy within a range of 0 to 5 eV, the organic sample being degradable above 5 eV;
c) a step of spectrally separating light within a range of 180 to 700 nm included in electromagnetic waves emitted from the organic sample, and measuring intensity

Assignees

• Univ Kyoto

Inventors

• Yoshida Hiroyuki

Classifications

• G01N21/66

  electrically excited, e.g. electroluminescence · CPC title

• G01J3/30 Primary

  Measuring the intensity of spectral lines directly on the spectrum itself (G01J3/42, G01J3/44 take precedence) · CPC title

• G01J3/443

  Emission spectrometry · CPC title

• H01J37/06

  Electron sources; Electron guns · CPC title

• G01N23/2251 Primary

  using incident electron beams, e.g. scanning electron microscopy [SEM] · CPC title