Dye-Sensitized Solar Cell Laminate Thermal Shrinkage Control
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Solution Overview
Problem
Conventional dye-sensitized solar cells with plastic film substrates face challenges in achieving high photovoltaic efficiency due to low charge transportation efficiency and mechanical instability, particularly when the porous semiconductor layer is sintered at high temperatures, leading to amorphous/crystalline phase transitions and potential cracking.
Innovation Solution
A laminate for dye-sensitized solar cells comprising a plastic film with controlled thermal shrinkage, a transparent conductive layer of indium oxide with zinc oxide, and a porous semiconductor layer of titanium, zinc, or tin oxide, sintered at a lower temperature to maintain mechanical integrity and enhance photovoltaic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a plastic film is used as a support for electrodes for dye-sensitized solar cells, then the solar cell becomes flexible and lightweight, but the porous semiconductor layer cannot be sintered at a sufficiently high temperature, resulting in low charge transportation efficiency
Solution Approach 1:
The patent changes the thermal parameters of the plastic film by controlling its thermal shrinkage rate to be 5°C or less per degree Celsius in the temperature range of 100-200°C. This parameter modification allows the film to maintain dimensional stability during low-temperature sintering (150-250°C), enabling sufficient charge transportation efficiency while preserving flexibility and lightweight properties.
2Reliability
If the sintering temperature for a porous semiconductor layer on a plastic film and ITO structure is elevated, then the transparent conductive layer undergoes amorphous/crystalline phase transition, worsening mechanical properties and causing cracking
Solution Approach 1:
The patent modifies the thermal parameters of both the plastic film (controlling thermal shrinkage rate to 5°C or less per degree Celsius between 100-200°C) and the transparent conductive layer (controlling crystallization temperature to 200°C or higher). These parameter changes enable sintering at 150-250°C where the transparent conductive layer remains amorphous, avoiding phase transitions and mechanical degradation while achieving sufficient photovoltaic performance.
Solution Approach 2:
The patent creates a composite structure consisting of a plastic film with specific thermal properties and a transparent conductive layer with controlled crystallization temperature. This composite material system allows the layers to work together during low-temperature sintering, maintaining mechanical integrity while achieving the desired photovoltaic function without high-temperature damage.
3Ease of manufacture
If an ordinary plastic film is used as a support, then the solar cell is inexpensive and highly-transparent, but the porous semiconductor layer cannot be sintered at a sufficiently high temperature, resulting in extremely inferior photovoltaic power generation performance
Solution Approach 1:
The patent transforms ordinary plastic film into a suitable support by modifying its thermal parameters, specifically controlling the thermal shrinkage rate to be 5°C or less per degree Celsius in the temperature range of 100-200°C. This parameter change enables the film to withstand sintering temperatures of 150-250°C without excessive deformation, achieving sufficient photovoltaic power generation performance while maintaining the advantages of being inexpensive and highly-transparent.
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 solution results in highly durable and flexible dye-sensitized solar cells with improved photovoltaic power generation efficiency and reduced time-dependent degradation, maintaining mechanical stability and efficiency over time.
Implementation Method 1
the transparent conductive layer becomes an amorphous state or a mixed amorphous/crystalline state. Accordingly, the electrode that comprises a plastic film and ITO may undergo amorphous/crystalline phase transition in sintering a porous semiconductor layer thereon
Implementation Method 2
the thermal shrinkage in the machine direction of the plastic film when heat-treated at 200° C. for 10 minutes is from −1.5 to +0.5%
Implementation Method 3
the porous semiconductor layer is formed by sintering fine particles. For forming the porous semiconductor layer, semiconductor particles must be sintered; and for increasing the charge transportation efficiency of the layer, the particles must be sintered at a sufficiently high temperature
Data Source
AI summary
A laminate for dye-sensitized solar cell comprising a plastic film of which the thermal shrinkage in the machine direction thereof when heat-treated at 200° C. for 10 minutes is from −1.5 to +0.5%, and a transparent conductive layer provided on the film, which comprises essentially indium oxide with zinc oxide added thereto and has a surface resistivity of at most 40 Ω/square, may give a highly-durable and flexible, dye-sensitized solar cells having high photovoltaic power generation efficiency.