Doped Silicon Defect Stabilization via High-Intensity Radiation
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Solution Overview
Problem
Existing methods for stabilizing silicon solar cells are inefficient in addressing electrically active defects that form post-processing, leading to light-induced degradation and reduced efficiency, as they require hours or days to stabilize, which is incompatible with high-throughput manufacturing.
Innovation Solution
A method involving exposure of doped silicon to high-intensity electromagnetic radiation (above 3 suns) to accelerate the formation and passivation of electrically active defects, with controlled temperature and radiation parameters to achieve rapid stabilization, typically within seconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stabilization techniques are used to reduce electrically active defects in silicon solar cells, then defect stabilization is achieved, but the process requires hours or days which is incompatible with high throughput manufacturing
Solution Approach 1:
The patent applies parameter changes by dramatically increasing the illumination intensity from conventional levels (1 sun) to high intensity levels (at least 3 suns, preferably 10-70 suns). This parameter change accelerates the defect formation and stabilization kinetics, reducing the stabilization time from hours or days to seconds or minutes, thereby resolving the contradiction between reliability and productivity
Solution Approach 2:
The patent implements preliminary action by performing defect stabilization before the solar cells are installed in modules. The method stabilizes electrically active defects in the silicon material during the manufacturing process itself, preventing future light-induced degradation and eliminating the need for prolonged field stabilization periods
2Speed
If high illumination intensity (above 1000 W/m2) is used to accelerate defect formation, then stabilization speed increases, but the acceleration decreases and reaches saturation
Solution Approach 1:
The patent applies dynamics by implementing a two-stage illumination protocol that adapts the illumination intensity over time. The method initially uses high intensity illumination (10-70 suns) to rapidly form defects, then reduces intensity to maintain excess carrier concentration without excessive energy input. This dynamic adjustment optimizes the stabilization rate while avoiding the diminishing returns that occur with sustained high-intensity illumination
3Productivity
If excess majority carrier concentration is maintained during radiation exposure, then defect formation is accelerated, but energy consumption increases
Solution Approach 1:
The patent applies partial or excessive action by maintaining excess majority carrier concentration at levels higher than 10% of the effective doping concentration during the critical defect formation period. This excessive carrier injection accelerates defect formation kinetics significantly. The method then reduces the excess carrier concentration to minimal levels after defect formation, thereby achieving high productivity during the critical phase while minimizing energy consumption during the maintenance phase
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 method rapidly stabilizes the silicon material, achieving 90% or better stabilization in a short time, with the ability to maintain defect concentration and prevent reactivation, thereby enhancing solar cell performance and efficiency.
Implementation Method 1
exposing a portion of the doped silicon to electromagnetic radiation in a manner such that photons with an energy higher than that of a bandgap of the silicon provide a radiation intensity of at least 3 suns
Implementation Method 2
exposing a portion of the silicon to the electromagnetic radiation and controlling a temperature of the silicon are performed in a manner such that electrically active defects are formed
Data Source
AI summary
The present disclosure provides a method for accelerating the formation of defects in doped silicon. A doped silicon area is exposed with high intensity electromagnetic radiation to provide a substantial excess of majority carriers and promote a high rate of defect formation to allow efficient silicon passivation.