Transparent Solar Contacts via 3D Light Redirection
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Solution Overview
Problem
Conventional solar cells with planar contacts suffer from significant reflection and absorption losses due to the interaction of incoming solar power with metal contacts, leading to reduced efficiency in electricity generation.
Innovation Solution
The development of effectively transparent contacts (ETCs) with three-dimensional shapes, such as triangular cross-sections, that redirect incident light onto the photoabsorbing surface, fabricated using a mold stamp with grooves filled with conductive ink, which are then cured and integrated onto existing or new contacts, enhancing transparency and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If planar metal contacts are used in solar cells, then electrical conductivity is achieved, but reflection and absorption losses increase
Solution Approach 1:
The patent transitions from conventional planar (2D) metal contacts to three-dimensionally structured contacts with vertical profiles. This dimensional change allows light to be redirected onto the photoabsorbing surface rather than being reflected or absorbed by the contacts, while the vertical conductive path maintains electrical connectivity. The 3D structure effectively separates the optical function (light redirection) from the electrical function (current collection).
Solution Approach 2:
The contact structure is designed with different properties at different locations: the upper portion has a reduced width or triangular cross-section optimized for light transparency and redirection, while the lower portion maintains sufficient width and conductivity for electrical current collection. This local differentiation allows the same contact to simultaneously minimize optical losses and maintain electrical performance.
2Loss of energy
If contact width is reduced to improve transparency, then reflection losses decrease, but electrical conductivity deteriorates
Solution Approach 1:
The patent introduces a vertical dimension to the contact structure, creating a three-dimensional profile instead of a purely planar design. This allows the contact to have a narrow upper width for transparency while maintaining adequate cross-sectional area through vertical extension, thereby preserving conductivity without sacrificing optical performance.
Solution Approach 2:
The contact is effectively segmented into functional zones: an upper section optimized for optical transparency with reduced width, and a lower section optimized for electrical conductivity with sufficient cross-section. This segmentation allows each portion to be optimized for its specific function without compromising the other.
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
ETCs mitigate reflection losses and maintain high conductivity, improving the overall efficiency of solar cells by redirecting incident photons onto the active surface without compromising electrical performance.
Implementation Method 1
effectively transparent contacts (ETCs) with three-dimensional shapes, such as triangular cross-sections, that redirect incident light onto the photoabsorbing surface
Implementation Method 2
The plurality of grooves is filled with conductive ink using capillary action
Implementation Method 3
curing the conductive ink, and removing the mold stamp such that the cured conductive ink remains on the metal contacts
Implementation Method 4
forming the effectively transparent metal contacts further includes annealing the cured conductive ink after the removal of the mold stamp from the photoabsorbing surface
Data Source
AI summary
In conventional solar cells with metal contacts, a non-negligible fraction of the incoming solar power is immediately lost either through absorption or reflection upon interaction with the contacts. Effectively transparent contacts (“ETCs”) for solar cells can be referred to as three-dimensional contacts designed to redirect incoming light onto a photoabsorbing surface of a solar cell. In many embodiments, the ETCs have triangular cross-sections. Such ETCs can be placed on a photoabsorbing surface such that at least one of their sides forms an angle with the photoabsorbing surface. In this configuration, the ETCs can redirect incident light onto the photoabsorbing surface, mitigating or eliminating reflection loss compared to conventional solar cells. When constructed in accordance with a number of embodiments of the invention, ETCs can be effectively transparent and highly conductive.