CIGS Solar Cell Absorber Surface Repair via Reducing Reagent Immersion

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Solution Overview

Problem

CIGS solar cell surfaces oxidize when exposed to the atmosphere, leading to reduced interface quality and photoluminescence intensity, which decreases solar cell efficiency.

Innovation Solution

Immersion of the oxidized CIGS absorber in a reducing reagent, such as sodium sulfite or Thiourea, to reverse surface oxidation and increase photoluminescence intensity, followed by deposition of a buffer layer to prevent further oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If CIGS absorber is exposed to atmosphere during manufacturing, then deposition and handling can be completed, but surface oxidation occurs reducing interface quality and photoluminescence intensity

Engineering Contradiction:

Improvemanufacturing throughputVSAvoidinterface quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies inert atmosphere by maintaining the CIGS absorber in a nitrogen-filled environment from deposition through handling and buffer layer deposition. The nitrogen atmosphere prevents oxygen exposure that would cause surface oxidation, thereby maintaining interface quality and photoluminescence intensity while enabling complete manufacturing processes to be completed.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Ease of operation

If CIGS absorber surface oxidizes, then handling in atmosphere is simplified, but photoluminescence intensity decreases reducing solar cell efficiency

Engineering Contradiction:

Improvehandling convenienceVSAvoidsolar cell efficiency

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent uses nitrogen atmosphere to protect the CIGS absorber surface during handling operations. This inert environment prevents oxidation while the absorber is outside the vacuum chamber, maintaining photoluminescence intensity and solar cell efficiency without complicating the handling process.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Adaptability or versatility

If buffer layer deposition is delayed, then manufacturing flexibility increases, but oxidized surface quality deteriorates

Engineering Contradiction:

Improveprocess flexibilityVSAvoidsurface quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent maintains the CIGS absorber in a nitrogen atmosphere during the interval between deposition and buffer layer deposition. This allows manufacturing flexibility and process adaptability while preventing surface oxidation, thereby preserving surface quality and interface characteristics for optimal solar cell performance.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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

Restoration of the CIGS surface quality results in increased photoluminescence intensity, enhancing solar cell efficiency and preventing further oxidation.

Implementation Method 1

immersing the CIGS absorber in a reduction reagent... The reduction reagent reverses the oxidation of the CIGS surface

Methodology Applied

Scientific EffectReduction: Reduction

Data Source

PatentUS9496452B2Method of absorber surface repairing by solution process

Publication Date: 2016.11.15 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Methods and systems for repairing oxidation of CIGS surfaces during manufacture of a CIGS solar cell are generally disclosed. Oxidation of an absorber reduces the photoluminescence intensity of the CIGS surface. The absorber is immersed in a reduction tank having a reducing reagent therein. The reducing reagent reverses the oxidation of the CIGS absorber, increasing the interface quality and corresponding photoluminescence intensity. After reversing the oxidation, a buffer layer is deposited on the CIGS absorber to prevent further surface oxidation.