JPH0543276B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a spectral sensitivity measurement method for evaluating a single layer solar cell using an amorphous semiconductor.

<Prior art> A sunglass solar cell using an amorphous semiconductor as an intrinsic semiconductor is irradiated with short-wavelength DC bias light to measure its spectral sensitivity, and a signal different from the spectral sensitivity under unbiased light is detected to detect the spectral sensitivity in the intrinsic semiconductor. There are already reports that analyze the weak electric field region. A conventional example of this is a metal-intrinsic amorphous semiconductor using hydrogenated amorphous silicon (hereinafter referred to as a-si:H) as an amorphous semiconductor.
Using an n-type amorphous semiconductor type Schottky solar cell and hydrogenated amorphous silicon germanium for the intrinsic semiconductor layer (hereinafter referred to as the i-layer),
A measurement example of a single solar cell in which a pin junction of a p-type semiconductor layer (hereinafter referred to as p-layer), an i-layer, and an n-type semiconductor layer (hereinafter referred to as n-layer) is formed is known. However, using these conventional measurement methods, solar cells with novel structures and a-Si:H can be measured using p-layer, i-layer,
A single solar cell (hereinafter referred to as SS/pin/ITO) in which a pin junction is formed on a stainless steel substrate (hereinafter referred to as SS) and an electrode of an ITO film (transparent conductive film) is provided on the stainless steel substrate (hereinafter referred to as SS) using as an n-layer. When measured, as shown in curves 1 and 2 in Figure 3, the difference between the spectral sensitivity under short wavelength bias light (curve 2) and the spectral sensitivity under unbiased light (curve 1) is extremely small; A problem arises in that it is difficult to accurately detect the effect of direct current bias light irradiation. The chopping frequency (hereinafter referred to as f) of the probe light used to measure the spectral sensitivity of this a-Si:H SS/pin/ITO solar cell under short wavelength DC bias light irradiation was a high value of 170Hz. It was hot.

<Object of the invention> In order to detect the effect of the short wavelength DC bias light described above, the present invention controls the value of f of the probe light, irradiates the solar cell with short wavelength bias light, and calculates the intensity of the spectral sensitivity signal. The purpose of this invention is to provide a method for measuring the spectral sensitivity of solar cells with increased spectral sensitivity.

<Summary of the Invention> In order to achieve the above object, the present invention reduces the chopping frequency f of the chopped probe light used when measuring the spectral sensitivity under short wavelength DC bias light irradiation in the spectral sensitivity measurement system of solar cells. It is characterized by performing spectral sensitivity detection with the measurement accuracy required by this method.

<Example> FIG. 1 is a block diagram of a spectral sensitivity measuring system for a solar cell, which is used to explain an example of the present invention.
As a sample, for example, SS/pin/ITO a-Si
A single layer (single) solar cell is used. to the sample
Using an Xe lamp as a light source, DC bias light is irradiated through an AM1.5 filter and a filter that passes short wavelengths, and probe light chopped from another Xe lamp light source through a spectrometer and a chopper is superimposed. At this time, the photocurrent that changes due to the probe light is detected by a lock-in amplifier, and the ratio to the light energy incident on the sample is determined, which is the spectral sensitivity of the sample under bias light.

As detailed in the prior art section, the solar cell in which the effect of short wavelength DC bias light could not be accurately detected at the chopping frequency f = 170 Hz of the probe light, that is, the SS/pin/ITO solar cell using a-Si:H Figure 2 shows the spectral sensitivity under short-wavelength DC bias light, measured by successively reducing f from 170Hz to 6Hz and using the same measurement conditions as in Figure 3, along with that under unbiased light. . In FIG. 2, curve 3 is a spectral sensitivity curve under unbiased light, and even if the chopping frequency f of the probe light is changed from 170 Hz to 6 Hz, it shows no dependence on f and the signal does not change. Curves 4 to 9 show the spectral sensitivities under short wavelength DC bias light;
f is 86Hz, 6 is f is 50Hz, 7 is f is 25Hz, 8 is f is
10Hz, 9 is a spectral sensitivity curve when f is 6Hz. As is clear from FIG. 2, as the value of f decreases, the difference between the spectral sensitivity curve under short wavelength bias light and the spectral sensitivity curve under non-bias light gradually increases. If this difference becomes large, the effect of short wavelength bias light irradiation can be detected with high precision.

As described above, desired spectral sensitivity data can be obtained by setting f to a value corresponding to the accuracy required for measurement.

In addition, the above example uses SS/pin/ITO as a sample.
Although the case where an a-Si:H type solar cell is used has been described, the present invention is not limited thereto.
SS/NIP/ITO solar cells using amorphous semiconductors and other types of single solar cells using amorphous semiconductors also show an increase in spectral sensitivity under short-wavelength DC bias light irradiation due to a reduction in f.

<Effects of the Invention> According to the present invention, it is possible to increase the spectral sensitivity signal of a single solar cell using an amorphous semiconductor under short wavelength DC bias light, so the effect of short wavelength DC bias light can be accurately and accurately evaluated. It is possible to accurately obtain information regarding the weak electric field region in the intrinsic semiconductor layer of a single solar cell.

[Brief explanation of the drawing]

Figure 1 shows SS/pin/ITO solar cell f=170Hz
These are the spectral sensitivities under short wavelength DC bias light and under non-bias light. FIG. 1 shows a system for measuring the spectral sensitivity of a solar cell under direct current bias light for explaining one embodiment of the present invention. Figure 2 shows SS/pin/
FIG. 2 is a characteristic diagram showing the dependence of spectral sensitivity on f of an ITO solar cell under short wavelength DC bias light and under non-bias light. Figure 3 shows f of SS/pip/ITO solar cell.
FIG. 2 is a characteristic diagram showing spectral sensitivity under short wavelength DC bias light and non-bias light at =170Hz. 1 to 9... Spectral sensitivity curve.

Claims (1)

[Claims] 1. In a solar cell spectral sensitivity measurement method in which spectral sensitivity is detected by irradiating a solar cell with probe light in a superimposed manner under irradiation with short-wavelength DC bias light, the probe light is tipped in accordance with the accuracy required for measurement. A method for measuring the spectral sensitivity of solar cells, characterized by controlling and setting the frequency.