Photosensitive Material Light-Intensity Switching for Photodetectors
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Solution Overview
Problem
Photodetectors with silicon-based or organic material-based photoactive layers often exhibit high dark current characteristics and reduced external quantum efficiency due to the inclusion of p-type or n-type semiconductor materials.
Innovation Solution
A photodetector incorporating a photoactive layer with a photosensitive material that undergoes a structural change from an open form to a ring structure in response to varying light intensities, allowing the device to function as both a photodiode at low light intensities and a photoconductor at higher light intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a p-type or n-type semiconductor material is used in the photoactive layer, then the photodetector can operate, but the dark current increases and external quantum efficiency decreases
Solution Approach 1:
The patent changes the operational parameters of the photodetector by utilizing light intensity-dependent switching between photodiode and photoconductor modes. The photosensitive material undergoes structural transformation (open form to ring structure) based on light intensity, which dynamically alters the LUMO energy level and electrical characteristics, thereby optimizing both dark current and external quantum efficiency under different operating conditions
Solution Approach 2:
The photodetector employs a dynamic operational mode that adapts to light intensity conditions. The photosensitive material structurally transforms from an open form at low light intensity to a ring structure at high light intensity, enabling the device to switch between photodiode and photoconductor modes. This dynamic behavior allows the system to maintain low dark current while achieving high external quantum efficiency when needed
2Reliability
If the photosensitive material is in the open form state, then the LUMO energy level is suitable for photodiode operation, but the photocurrent density is limited under high light intensity
Solution Approach 1:
The patent utilizes light intensity as a control parameter to induce structural changes in the photosensitive material. Under low light intensity, the material maintains its open form with a LUMO energy level of at least −3 eV, suitable for photodiode operation. Under high light intensity, the material transforms to a ring structure with LUMO energy level less than −3 eV, enabling photoconductor mode with higher photocurrent density
Solution Approach 2:
The photosensitive material exhibits dynamic structural transformation between open and ring forms based on light intensity. This dynamic behavior enables the photodetector to automatically switch between photodiode and photoconductor operational modes, optimizing performance across different light conditions without requiring external control mechanisms
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
The photodetector achieves low dark current characteristics and high external quantum efficiency by switching between photodiode and photoconductor modes based on light intensity, enabling effective detection under both low-light and high-light conditions.
Implementation Method 1
A photodetector may include a photoactive layer having a photocurrent density of at most about 10−6 A/cm2 under a first incidence condition, and having a photocurrent density of at least about 10−4 A/cm2 under a second incidence condition. The photosensitive material may have: a first state represented by Chemical Formula 1; and a second state in which a carbon to which R3 is bonded and a carbon to which R4 is bonded are connected to each other to form a ring structure.
Implementation Method 2
A photodetector is an element configured to transfer an optical signal to an electrical signal. The photodetector achieves low dark current characteristics and high external quantum efficiency by switching between photodiode and photoconductor modes based on light intensity.
Implementation Method 3
the photoactive layer and the first electrode forms a Schottky junction under the first incidence condition, and the photoactive layer and the first electrode forms an ohmic junction under the second incidence condition
Data Source
AI summary
Provided is a photosensitive material and a photodetector including the same. According to the present invention, the photodetector may include a photoactive layer having a photocurrent density of at most about 10−6 A/cm2 under a first incidence condition, and having a photocurrent density of at least about 10−4 A/cm2 under a second incidence condition. The wavelength of light under the second incidence condition is the same as the wavelength of light under the first incidence condition, and the intensity of light under the second incidence condition may be greater than the intensity of light under the first incidence condition.