Large Area Organic Photovoltaics CO2 Snow Cleaning
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Solution Overview
Problem
Existing organic photovoltaic (OPV) devices face challenges in maintaining high yield and performance, particularly in large-area cells, due to electrical shorts caused by particulates on substrates, which are not effectively addressed by conventional cleaning methods.
Innovation Solution
The process involves using CO2 snow cleaning to remove particulates from substrates, creating a surface free of contaminants before depositing organic layers, thereby reducing shorts and improving yield without compromising efficiency, and employing a subelectrode structure to minimize series resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solvent cleaning is used on substrates, then the cleaning process is simple and cost-effective, but particulates remain on the substrate causing electrical shorts in large-area OPV devices
Solution Approach 1:
The patent replaces conventional chemical solvent cleaning with a mechanical/physical cleaning method using a stream of solid particles (CO2 snow) to remove particulates from substrates. This mechanical cleaning approach effectively removes contaminants that cause electrical shorts without the limitations of solvent cleaning, thereby improving device yield and reliability.
Solution Approach 2:
The patent changes the physical state and parameters of the cleaning medium from liquid solvent to solid particle stream (CO2 snow). By controlling the temperature, pressure, and flow characteristics of the CO2 snow stream, the cleaning process achieves effective particulate removal while preventing damage to the substrate, resolving the contradiction between cleaning effectiveness and substrate integrity.
2Power
If the active area of OPV devices is increased to improve power output, then the energy generation capacity increases, but series resistance increases and yield decreases due to particulate contamination
Solution Approach 1:
The patent applies preliminary cleaning action using CO2 snow before depositing organic layers on the substrate. This pre-cleaning step removes particulates that would otherwise cause electrical shorts and increase series resistance in large-area devices, enabling successful fabrication of high-power OPV modules with improved yield and reduced complexity.
3Reliability
If CO2 snow cleaning is used to remove particulates, then yield and device performance improve, but the process complexity and equipment requirements increase
Solution Approach 1:
The patent utilizes phase transitions of CO2 (between solid, liquid, and gas phases) to create the cleaning snow stream and facilitate particulate removal. The phase change properties of CO2 enable effective cleaning while allowing for relatively simple process control and equipment design, balancing improved reliability with manageable process complexity.
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 increases the yield of large-area OPV devices by reducing electrical shorts and maintaining high power conversion efficiency, with CO2 snow cleaning proving more effective than conventional solvent cleaning and allowing for larger active areas with improved fill factor and reduced series resistance.
Implementation Method 1
cleaning a surface of the substrate by exposing the surface to a stream of at least one compound comprising one or more phases chosen from supercritical, gaseous, solid, and liquid phases
Implementation Method 2
Photosensitive optoelectronic devices convert electromagnetic radiation into electricity
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3
AI summary
Disclosed herein are large area, multi-layer solar devices comprising a substrate, an active area comprising at least one donor material and at least one acceptor material deposited on a surface of the substrate, wherein the donor and acceptor materials are comprised of organic molecules, and wherein particulates are removed from the surface of the substrate before deposition of the donor and acceptor materials. Particulates may be removed by exposing the surface of the substrate to a stream of at least one compound comprising one or more phases chosen from supercritical, gaseous, solid, and liquid phases. Also disclosed are methods of manufacturing photovoltaic devices comprising providing a substrate, cleaning a surface of the substrate by exposing the surface to a stream of at least one compound comprising one or more phases chosen from supercritical, gaseous, solid, and liquid phases, and depositing an organic active layer on the surface of the substrate.