Shortwave Infrared Nanoparticles With Tunable Band Gap Layers

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Solution Overview

Problem

Current shortwave infrared nanoparticles have limitations in quantum efficiency, emission wavelength control, and penetration depth in biological tissues, making them unsuitable for advanced bioimaging and multiplexed imaging applications.

Innovation Solution

The development of nanoparticles with a core, intermediate, and outer layer structure, where the intermediate layer has a smaller band gap energy than the core and outer layer, allowing for adjustable emission wavelengths and high quantum efficiency, achieved through specific material compositions and layer thicknesses, such as CdSe, HgCdSe, and CdS, with the intermediate layer being 0.3 nm to 1.2 nm thick and the outer layer providing passivation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional semiconductor nanoparticles (quantum dots) with nucleus/shell structure are used, then emission wavelength can be freely controlled, but quantum efficiency is relatively low and penetration depth in biological tissues is limited

Engineering Contradiction:

Improveemission wavelength controlVSAvoidquantum efficiency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating distinct layers with different band gap energies within the nanoparticle structure. The intermediate layer with smaller band gap energy (E2) is positioned between the core (E1) and outer layer (E3), allowing each region to contribute differently to the overall optical properties. This spatial differentiation of material properties enables both wavelength control and enhanced quantum efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining multiple semiconductor materials with different band gap energies in a core-intermediate-outer layer structure. This composite approach integrates the advantages of different materials: the core provides structural stability, the intermediate layer enables tunable emission in the 1000-1700 nm range with high efficiency, and the outer layer provides protection and additional optical control.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional semiconductor nanoparticles are used, then quantum efficiency is improved compared to other materials, but emission spectrum is wide and it is difficult to control the emission wavelength band for multiplexed imaging

Engineering Contradiction:

Improvequantum efficiencyVSAvoidemission wavelength band control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent utilizes parameter changes by systematically varying the band gap energy parameter across different layers. The intermediate layer's band gap energy (E2) is specifically engineered to be smaller than both the core (E1) and outer layer (E3), creating a precise energy gradient that controls emission wavelength. By adjusting the composition and thickness of the intermediate layer, the emission spectrum can be precisely tuned to narrow bands within the 1000-1700 nm range.

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If lanthanide-doped nanoparticles are used, then shortwave infrared luminescence is achieved, but emission wavelength cannot be freely controlled and brightness is limited due to low extinction coefficient

Engineering Contradiction:

Improveshortwave infrared luminescenceVSAvoidemission wavelength control

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the lanthanide ion doping mechanism with a semiconductor band gap engineering approach. Instead of relying on f-f transitions of lanthanide ions which have fixed emission wavelengths and low extinction coefficients, the invention uses direct band gap transitions in semiconductor materials with tunable band gap energies. This substitution enables both high brightness and free emission wavelength control through material composition and layer thickness adjustment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

These nanoparticles exhibit high quantum efficiency of 60% or more, enabling deeper penetration and narrower emission spectra, facilitating advanced bioimaging and multiplexed imaging with improved resolution and depth compared to existing technologies.

Implementation Method 1

an intermediate layer that is formed on the core and has band gap energy of E2, in which a size of the E2 is smaller than a size of the E1 and a size of the E3

Methodology Applied

Scientific EffectBand gap energy transition: Photoluminescence

Data Source

PatentUS11613700B2Highly emissive short wave infrared nanoparticles and method for preparing the same

Publication Date: 2023.03.28 DAEGU GYEONGBUK INSTITUTE OF SCIENCE AND TECHNOLOGY

AI summary

The present invention provides shortwave infrared ray emitting nanoparticles including a core having band gap energy of E1; an intermediate layer that is formed on the core and has band gap energy of E2; and an outer layer that is formed on the intermediate layer and has band gap energy of E3, in which the size of the E2 is smaller than the size of the E1 and the size of the E3. According to the present invention, it is possible to provide a solar cell which is improved in efficiency and life span and can be produced by a solution process.