Carbon Nanotube Cable Electrodes for Photovoltaic Light Penetration

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Solution Overview

Problem

Conventional photovoltaic devices face challenges with low durability and photoelectric conversion efficiency due to the use of conductive metals for electrodes, which are not transparent and have uneven resistance distribution, especially when using transparent conductive materials like indium tin oxide (ITO).

Innovation Solution

A photovoltaic device design featuring a silicon substrate with cavities for enhanced light collation and a first electrode composed of carbon nanotube cables, which are arranged in parallel or a net-like structure to improve light penetration and resistance distribution, combined with metal strips for enhanced conductivity and an anti-reflection layer to boost energy conversion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conductive metals (Al, Ag, Cu) are used for electrodes, then electrical conductivity is improved, but light transparency deteriorates

Engineering Contradiction:

Improveelectrical conductivityVSAvoidlight transparency

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent uses carbon nanotubes as a composite material that combines the electrical conductivity of metals with the light transparency of non-metallic materials. The carbon nanotube cable electrode maintains high electrical conductivity while allowing light to pass through, resolving the contradiction between conductivity and transparency.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The carbon nanotube cable electrode provides localized high conductivity where needed while maintaining overall transparency. The cable structure concentrates conductive properties in specific regions (the cable itself) while the surrounding areas remain transparent to light.

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If transparent conductive material (ITO) is used for front electrode, then light transparency is improved, but chemical and mechanical durability deteriorates

Engineering Contradiction:

Improvelight transparencyVSAvoidchemical and mechanical durability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent replaces fragile ITO with carbon nanotube cables that form a mechanically robust composite structure. The carbon nanotubes provide both transparency and enhanced mechanical strength, eliminating the durability problems associated with ITO while maintaining light transparency.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters from brittle oxide (ITO) to flexible carbon-based structures. This parameter change improves mechanical durability and chemical stability while preserving the transparent conductive properties needed for photovoltaic operation.

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If ITO material is used for front electrode, then light transparency is improved, but resistance distribution uniformity deteriorates

Engineering Contradiction:

Improvelight transparencyVSAvoidresistance distribution uniformity

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent divides the electrode into multiple carbon nanotube cables arranged in a grid pattern. This segmentation creates numerous small conductive pathways that distribute resistance more uniformly across the electrode surface, eliminating the uneven resistance distribution problem of ITO.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The carbon nanotube cable structure creates a composite electrode system where multiple conductive elements work together to achieve uniform resistance distribution. The network of cables provides redundant conductive paths that balance out resistance variations.

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 design results in a more durable and efficient photovoltaic device with improved light penetration and uniform resistance distribution, leading to enhanced energy conversion efficiency and increased durability.

Implementation Method 1

a first electrode 16 including a plurality of carbon nanotube (CNT) cables 161

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

The photovoltaic cell or the solar cell is a device that converts light into electrical energy using the photoelectric effect

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

an anti-reflection layer to boost energy conversion efficiency

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS8263860B2Silicon photovoltaic device with carbon nanotube cable electrode

Publication Date: 2012.09.11 HON HAI PRECISION INDUSTRY CO LTD

AI summary

A photovoltaic device includes a silicon substrate, a doped silicon layer, a first electrode and a second electrode. The silicon substrate has a plurality of cavities defined therein. The doped silicon layer is formed in contact the silicon substrate. The first electrode including a plurality of carbon nanotube cables is adjacent to the silicon substrate. The second electrode is attached to the silicon substrate.