Optical Sensor Using Luminescent Quantum Dot Arrays for Nanoscale Charge Tracking
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Solution Overview
Problem
Current optical methods for sensing buried charges in samples face challenges due to poor spatial resolution and difficulties in accurately assembling single molecules with nanometer resolution, limiting the ability to track charge dynamics effectively.
Innovation Solution
An optical sensor apparatus using luminescent quantum dots as probes, which are optically excited and detected to determine correlations that allow for simultaneous sensing of electric, magnetic, and temperature properties, with a circuit to analyze these correlations and locate electric charges, and a fabrication method involving a bilayer structure to precisely arrange quantum dots on a substrate or sample surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single molecules are used as nanoprobes to detect charge trajectory, then sub-nanometer resolution can be achieved, but accurate assembly of single molecules with nanometer resolution becomes extremely difficult
Solution Approach 1:
The probe is segmented into multiple quantum dots arranged in an array, where each quantum dot can independently sense charges at different locations. This segmentation allows the system to achieve high spatial resolution through the collective information from multiple probes rather than relying on a single perfectly positioned molecule.
Solution Approach 2:
Instead of using a single unique molecule, the invention uses multiple identical or similar quantum dots as copies. These quantum dots are arranged in an array and each can detect charges independently. The redundancy of having multiple copies compensates for the inability to precisely control the position of individual molecules, while still achieving sub-nanometer resolution through the array configuration.
2Ease of operation
If optical methods are used to sense buried charges, then the limitation of scanning probe microscopy can be overcome, but spatial resolution deteriorates due to the diffraction limit of light
Solution Approach 1:
Quantum dots are introduced as intermediary objects between the optical detection system and the buried charges. The quantum dots act as mediators that convert the interaction with charges into optical signals that can be detected with high spatial resolution, effectively bridging the gap between optical methods and nanoscale charge detection.
Solution Approach 2:
The quantum dots are positioned in close proximity to the sample surface, creating a localized sensing region. This local positioning allows the optical signals from individual quantum dots to be influenced primarily by charges in their immediate vicinity, thereby achieving high spatial resolution despite the diffraction limit of light.
3Adaptability or versatility
If quantum dots are arranged in an array configuration, then simultaneous sensing of multiple properties can be achieved, but device complexity increases
Solution Approach 1:
The quantum dot array is designed to perform multiple sensing functions simultaneously. Each quantum dot can detect different properties such as electric charge, magnetic field, and temperature depending on its specific configuration and the measurement mode used. This multi-functionality is achieved through a unified array structure rather than requiring separate specialized probes for each measurement type.
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
Enables high-resolution sensing of electric, magnetic, and temperature properties at the nanoscale, allowing for accurate tracking of charge positions and dynamics, overcoming the limitations of existing methods by providing improved spatial resolution and precise probe placement.
Implementation Method 1
a probe, comprising an arrangement of luminescent quantum dots; an optical source, configured to optically excite the luminescent quantum dots; an optical detector, configured to read optical signals from the quantum dots
Implementation Method 2
single molecules are used as nanoprobes to detect the trajectory of an elementary charge... the determination of a single electron displacement can be obtained with sub-nanometer resolution... optical signals transmitted by each of the quantum dots are influenced by the sample
Data Source
AI summary
An optical sensor apparatus is disclosed. The apparatus comprises: a sample holder, configured to hold a sample, in operation; a probe, comprising an arrangement of luminescent quantum dots; an optical source, configured to optically excite the luminescent quantum dots; an optical detector, configured to read optical signals from the quantum dots; and a circuit. The circuit is connected to the optical detector and configured to determine correlations between optical signals read by the optical detector. The probe is positioned or positionable relatively to, e.g., at a distance from, the sample, such that optical signals transmitted by each of the quantum dots are influenced by the sample, in operation. The present invention is further directed to related methods of operation and fabrication methods.