Ni-Doped CuS Counter Electrode for QDSSC Efficiency

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Solution Overview

Problem

Quantum dot-sensitized solar cells (QDSSCs) have low efficiency due to poor electrocatalytic activity and stability of traditional counter electrodes, particularly when using platinum, and existing metal sulfide counter electrodes like CuxS suffer from corrosion issues with polysulfide redox couples.

Innovation Solution

A Ni-doped CuS thin film counter electrode is used, fabricated via chemical bath deposition on a fluorine-doped tin oxide substrate, offering enhanced electrocatalytic activity and low charge transfer resistance, which improves the efficiency and stability of QDSSCs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If platinum is used as counter electrode in QDSSCs, then electrocatalytic activity is improved, but chemisorption of electrolyte species and poor optimization for polysulfide redox couple occur

Engineering Contradiction:

Improveelectrocatalytic activityVSAvoidchemisorption of electrolyte species

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces expensive platinum with cost-effective metal sulfide materials (CuS, NiS, CoS, PbS) that provide comparable or superior electrocatalytic activity for polysulfide redox couples, eliminating the harmful chemisorption issue while reducing cost

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent modifies the counter electrode material composition by using metal sulfides with different band structures and surface properties that are optimized for polysulfide redox couple reactions, changing the chemical interaction parameters to prevent harmful chemisorption

Inventive Principle:

Principle #35Parameter changes

2Reliability

If CuxS counter electrodes are developed in situ on brass sheet, then electrocatalytic activity is improved, but continuous corrosion by polysulfide redox couple results in low chemical and mechanical stability

Engineering Contradiction:

Improveelectrocatalytic activityVSAvoidchemical and mechanical stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses composite metal sulfide structures (CuS, NiS, CoS, PbS) deposited on conductive substrates like FTO, combining the electrocatalytic benefits of metal sulfides with the stability of oxide-coated substrates, preventing corrosion while maintaining activity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent replaces the unstable in situ grown CuxS on brass with more stable metal sulfide materials deposited on corrosion-resistant substrates, eliminating the continuous corrosion problem

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If traditional counter electrodes are used in QDSSCs, then device simplicity is maintained, but power conversion efficiency remains low at approximately 13%

Engineering Contradiction:

Improvestructure simplicityVSAvoidpower conversion efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent optimizes the counter electrode material parameters by selecting metal sulfides with appropriate band gaps, conductivity, and surface area, achieving enhanced power conversion efficiency while maintaining the simple QDSSC structure

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite metal sulfide counter electrodes that combine multiple beneficial properties (high electrocatalytic activity, good conductivity, large surface area) to achieve higher efficiency without complicating the overall device architecture

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 Ni-doped CuS counter electrode achieves a higher power conversion efficiency of 4.36% compared to 3.24% with bare CuS, with improved electrocatalytic activity and reduced charge transfer resistance, enhancing the overall performance of QDSSCs.

Implementation Method 1

the CE's function is to collect electrons from external circuits and catalyze the reduction of oxidized species in the electrolytes

Methodology Applied

Scientific EffectElectrocatalysis: Catalysis

Implementation Method 2

quantum dot-sensitized solar cells (QDSSCs) are considered to be one of the most promising third generation solar cells

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 3

A Ni-doped CuS thin film counter electrode is used, fabricated via chemical bath deposition on a fluorine-doped tin oxide substrate

Methodology Applied

Scientific EffectChemical deposition: Deposition (physical)

Data Source

PatentUS10916380B1Quantum dot-sensitized solar cell and method of making the same

Publication Date: 2021.02.09 UNITED ARAB EMIRATES UNIVERSITY

AI summary

A quantum dot sensitized solar cell (QDSSC) includes a highly catalytic Ni-doped CuS thin film as a counter electrode (CE). The Ni-doped CuS CE can deliver outstanding electrocatalytic activity, conductivity, and low-charge transfer resistance at the CE/electrolyte interface. As a result, the QDSSC can achieve higher efficiency (η=4.36%) than a QDSSC with a bare CuS CE (3.24%).