Transient Absorption Spectrometer Pulse Current Excitation
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Solution Overview
Problem
Existing transient absorption technologies are unable to comprehensively and accurately measure the dynamics information of carriers excited by electro-excitation, limiting the analysis of excited state dynamics in samples like LEDs and solar cells.
Innovation Solution
A transient absorption spectrometer using a pulse current for excitation, which generates a current pulse signal to induce a non-luminous excited state or electroluminescent signal in samples, combined with a pulsed optical signal and data processing to obtain accurate transient absorption signals, excluding luminescent and photoconductive effects for enhanced measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a pulsed laser is used to excite the sample in existing transient absorption technology, then the absorption coefficient of the sample can be changed and transient absorption spectra can be obtained, but it is impossible to measure the dynamics information of carriers excited by electro-excitation comprehensively and accurately
Solution Approach 1:
The patent changes the excitation parameter from optical (pulsed laser) to electrical (current pulse signal), enabling the measurement of carrier dynamics under electro-excitation conditions. This parameter change allows the system to adapt to different excitation types while maintaining measurement capability, directly resolving the contradiction between versatility and measurement precision for different excitation modes.
2Measurement precision
If the detection light irradiates the sample during electro-excitation, then the absorption changes can be detected, but luminescent signals and photoconductive effects interfere with the measurement accuracy
Solution Approach 1:
The patent extracts and separates the harmful luminescent signals and photoconductive effects from the detection process. By using a beam splitter to divide the detection light into reference and measurement paths, and by subtracting the reference signal from the sample signal, the system removes the interfering luminescent components while preserving the actual absorption changes, thus resolving the contradiction between detection sensitivity and signal interference.
3Measurement precision
If a beam splitter is used to separate detection light into reference and measurement beams, then the measurement accuracy is improved by eliminating fluctuations, but the device complexity increases
Solution Approach 1:
The patent introduces a beam splitter as an intermediary component that divides the detection light into two separate paths: one serving as a reference and the other as a measurement beam. This intermediary element enables the system to compensate for optical fluctuations by comparing the reference signal with the sample signal, achieving improved measurement stability while maintaining a relatively simple overall device structure through the use of this single additional component.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for more comprehensive and accurate measurement of carrier dynamics, including generation and attenuation of transient components, providing crucial insights into excited state dynamics and performance evaluation of devices like LEDs and solar cells.
Implementation Method 1
a pulse generator configured to generate a current pulse signal under an action of a first trigger signal sent by the central control unit, where the current pulse signal is applied to a sample to be tested such that the sample is in a non-luminous excited state for single-carrier injection or an electroluminescent signal is generated
Implementation Method 2
a laser configured to emit a pulsed optical signal under an action of a second trigger signal sent by the central control unit
Implementation Method 3
a beam splitter disposed in a light-exiting direction of the laser, and configured to split the pulsed optical signal into a detection optical signal and a reference optical signal
Implementation Method 4
a data acquisition unit configured to acquire, under an action of a third trigger signal and a fourth trigger signal sent by the central control unit, the electroluminescent signal, the detected optical signal and the reference optical signal, and perform a processing to obtain electrical signal data indicating, at a single time instant, absorption intensities of the sample for optical signals of different wavelengths
Data Source
AI summary
A transient absorption spectrometer using excitation by a pulse current, including: a central control unit; a pulse generator configured to generate a current pulse signal under an action of a first trigger signal sent by the central control unit, where the current pulse signal is applied to a sample to be tested such that the sample is in a non-luminous excited state for single-carrier injection or a luminous excited state for luminescence in which an electroluminescent signal is generated; a laser configured to emit a pulsed optical signal under an action of a second trigger signal sent by the central control unit; a beam splitter disposed in a light-exiting direction of the laser, and configured to split the pulsed optical signal into a detection optical signal and a reference optical signal, where the detection optical signal irradiates the sample to be tested to generate a detected optical signal; a data acquisition unit configured to acquire, under an action of a third trigger signal and a fourth trigger signal sent by the central control unit, the electroluminescent signal, the detected optical signal and the reference optical signal, and perform a processing to obtain electrical signal data indicating, at a single time instant, absorption intensities of the sample for optical signals of different wavelengths; and a data processing and imaging unit configured to process the electrical signal data to obtain a transient absorption signal of the sample to be tested and perform imaging.