Multi-heterojunction Nanoparticles for Carrier Injection

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Solution Overview

Problem

Existing semiconductor nanocrystals with single heterojunctions face limitations in carrier injection processes due to large band gaps and offsets, hindering their performance in optoelectronic devices like LEDs and solar cells.

Innovation Solution

Development of passivated nanocrystalline semiconductor nanoparticles with multiple heterojunctions, featuring endcaps of different semiconductors at opposing ends and nodes on the radial surface, allowing for tunable band gaps and enhanced charge carrier injection and photoluminescence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If single heterojunction nanocrystals are used, then the structure is simple, but the carrier injection process is hindered due to large band gaps and offsets

Engineering Contradiction:
Improvestructure complexityVSAvoidcarrier injection efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The nanocrystal structure is segmented into multiple heterojunction interfaces with different band offsets, allowing independent optimization of carrier injection and blocking functions at each interface, thereby resolving the contradiction between structural simplicity and carrier injection efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the nanocrystal structure are assigned different semiconductor materials with specific band gap properties, creating localized heterojunctions that provide tailored electronic properties for carrier injection and blocking at specific locations

Inventive Principle:
Principle #3Local quality

2Reliability

If multiple heterojunctions are introduced, then carrier injection and photoluminescence are improved, but the device complexity increases

Engineering Contradiction:
Improvecarrier injection efficiencyVSAvoidheterojunction structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple heterojunction interfaces are nested within a single nanocrystal structure, with each interface contributing specific functionality, allowing complex carrier management capabilities to be achieved within a compact integrated structure

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The nanocrystal employs composite semiconductor materials with different band gaps and offsets to create multiple heterojunctions, combining the advantages of different materials to achieve superior carrier injection and photoluminescence performance

Inventive Principle:
Principle #40Composite materials

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 multi-heterojunction nanoparticles improve light emission efficiency and charge carrier management, facilitating the creation of high-performance optoelectronic devices with enhanced photoluminescence and charge separation capabilities.

Implementation Method 1

the heterojunction that is formed at the interface of dissimilar semiconductors can help to direct electrons and holes as well as being an active component for a variety of devices

Methodology Applied
Scientific EffectBand offset:

Implementation Method 2

improving photoluminescence efficiency

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 3

the stepwise band structure of ZnO/CdS/CdTe is conducive to improving charge separation and extending the electron diffusion length

Methodology Applied
Scientific EffectCharge separation:

Implementation Method 4

extending the electron diffusion length

Methodology Applied
Scientific EffectElectron diffusion: Diffusion

Data Source

PatentEP2778122B1Multi-heterojunction nanoparticles and articles comprising the same
Publication Date: 2021.04.28 DOW GLOBAL TECHNOLOGIES LLC
  • EP2778122B1 patent drawingFigure 1(A)
  • EP2778122B1 patent drawingFigure 1(B)
  • EP2778122B1 patent drawingFigure 2

AI summary

Disclosed herein is a semiconducting nanoparticle (100) comprising a one-dimensional semiconducting nanoparticle (102), for example a nanowire, having a first end and a second end; where the second end is opposed to the first end; and two first endcaps (108), one of which contacts the first end and the other of which contacts the second end respectively of the one-dimensional semiconducting nanoparticle; where the first endcap that contacts the first end comprises a first semiconductor and where the first endcap extends from the first end of the one-dimensional semiconducting nanoparticle to form a first nanocrystal heterojunction (103); where the first endcap that contacts the second end comprises a second semiconductor; where the first endcap extends from the second end of the one-dimensional semiconducting nanoparticle to form a second nanocrystal heterojunction (103); and where the first semiconductor and the second semiconductor are chemically different from each other.