3D Semiconductor Pillar Arrays for Flexible Optoelectronics

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Solution Overview

Problem

Conventional mesoscopic optoelectronic devices, such as solar cells, face limitations in efficiency and cost due to their flat morphology, which restricts the active surface area for light absorption and energy conversion, and are often rigid, making them unsuitable for flexible applications.

Innovation Solution

The development of a fabrication process using inkjet printing to create three-dimensional arrays of semiconductor micro- or nano-pillars from inorganic, organic, and hybrid materials, enhancing the active surface area and mechanical flexibility of mesoscopic optoelectronic devices, allowing for increased light-to-energy conversion efficiency and resistance to mechanical failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If flat morphology is used in conventional mesoscopic optoelectronic devices, then manufacturing is simpler, but the active surface area for light absorption is limited

Engineering Contradiction:
Improveactive surface areaVSAvoidstructure complexity
Core Design Contradiction:
Area of moving objectVSDevice complexity

Solution Approach 1:

The patent transitions from flat 2D morphology to three-dimensional 3D arrays of micro- or nano-pillars, adding vertical dimensionality to maximize light absorption. The pillars are arranged in periodic arrays with optimized dimensions (diameter 1-100 μm, height 10-1000 μm) to increase active surface area by up to 4,000% compared to flat structures, while maintaining manufacturability through inkjet printing deposition from suspensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If rigid substrates are used in conventional devices, then structural stability is improved, but flexibility and adaptability are reduced

Engineering Contradiction:
ImproveflexibilityVSAvoidstructural stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs flexible substrates such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) instead of rigid substrates. These flexible substrates support the 3D pillar arrays while enabling mechanical flexibility, allowing the devices to be bent or conform to curved surfaces. The mesoscopic pillar structure itself provides mechanical resilience, resisting failure during bending operations.

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If inkjet printing is used to create 3D pillar arrays, then manufacturing precision and pattern control are improved, but process complexity increases

Engineering Contradiction:
Improvepattern controlVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The inkjet printing process deposits semiconductor material suspensions that self-assemble into three-dimensional pillar structures through controlled drying and sintering. The process uses standard inkjet printing technology with commercially available suspensions containing semiconductor particles (e.g., TiO2, ZnO, CdSe) in liquid vehicles, allowing direct writing of periodic pillar arrays without complex lithography or self-assembly steps. The pillar formation is achieved through simple droplet deposition and thermal processing.

Inventive Principle:
Principle #25Self-service

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 significantly enhances the active surface area by up to 4,000% compared to conventional solar cells, improving energy conversion efficiency and enabling the use of flexible substrates, thus overcoming the limitations of traditional devices in terms of cost and application flexibility.

Implementation Method 1

The innovative fabrication method proposed uses as preferential chemical deposition technique which is inkjet printing that allows simultaneous micro-patterning or submicro-patterning of the proposed micro- or nano-pillars

Methodology Applied
Scientific EffectInkjet printing:

Implementation Method 2

The mesoscopic devices of the present invention employ 3D structures which additionally increase the surface area of the device composed of an interpenetrating network of inorganic, organic or hybrid semiconductor particles

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP2649653B1Mesoscopic optoelectronic devices comprising arrays of semiconductor pillars deposited from a suspension and production method thereof
Publication Date: 2021.05.05 FACULDADE DE CIENCIAS E TECHA DA UNIV NOVA DE LISBOA
  • EP2649653B1 patent drawingFigure 1a~1c
  • EP2649653B1 patent drawingFigure 2a~2d
  • EP2649653B1 patent drawingFigure 3a~3s

AI summary

The invention illustrates an innovative way to fabricate low cost, efficient, rigid or flexible mesoscopic optoelectronic devices such as photovoltaic (PV) solar cells or photo sensors (b) comprising three-dimensional arrays of semi-conductive micro- or nano-pillars (3b) deposited from suspensions e.g. by inkjet printing. Said pillars additionally increase the surface area of the device composed of an interpenetrating network of semiconductor particles of mesoscopic (2-50 nm) size forming junctions. In the present invention the active surface area is significantly increased when compared to previous flat structures (a, 3a), being fabricated preferably by inkjet patterning. Additionally, the invention allows for production of much more functional devices when compared with conventional mesoscopic PV cells due to smaller structure density what makes the layer more resistive to mechanical failure when bending. The invention also describes the device substrate (1), contact and electrode (2, 8), ion conductor (6) and fabrication parameters (h, d).