Photovoltaic Device Light Trapping via Back-Side Diffuser
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solar cells have low efficiency and high production costs, limiting their adoption as a mainstream energy source due to inefficiencies in converting solar energy into electric energy.
Innovation Solution
The development of a photovoltaic device with a p+-doped and n-doped layer forming a p-n junction, combined with a window layer and an antireflective coating on the front side, and a diffuser on the back side to enhance light trapping and absorption, utilizing epitaxial layers and techniques like molecular beam epitaxy for semiconductor growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional solar cell structures are used, then manufacturing costs are reduced, but light absorption efficiency is insufficient
Solution Approach 1:
The solar cell structure is divided into multiple functional layers including a window layer, p-n junction layer, and diffuser layer, with each layer performing a specific function to optimize light absorption and charge separation while maintaining manufacturing feasibility
Solution Approach 2:
A diffuser layer is added to the back surface of the solar cell to create light scattering in multiple dimensions, increasing the optical path length and absorption efficiency without significantly increasing the front surface complexity
2Productivity
If light absorption is increased through additional layers, then energy conversion efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The window layer serves multiple functions: it provides a low-recombination surface for the p-n junction, allows light transmission to the active layer, and can be integrated with the same semiconductor material system used for the p-n junction, simplifying the manufacturing process
Solution Approach 2:
The diffuser layer modifies the optical parameters at the back surface by creating a textured or scattering interface, increasing light trapping without requiring additional complex materials or processing steps beyond standard semiconductor fabrication
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 configuration significantly increases the efficiency of solar energy conversion by capturing and absorbing nearly all impinging photons, leading to improved voltage and current output compared to conventional solar cells.
Implementation Method 1
the junction of a solar cell absorbs photons to produce electron-hole pairs, which are separated by the internal electric field of the junction to generate a voltage, thereby converting light energy to electric energy
Implementation Method 2
an antireflective coating disposed above the window layer
Implementation Method 3
a diffuser disposed below the p+-doped layer
Data Source
AI summary
Methods and apparatus are provided for converting electromagnetic radiation, such as solar energy, into electric energy with increased efficiency when compared to conventional solar cells. A photovoltaic (PV) device may incorporate front side and/or back side light trapping techniques in an effort to absorb as many of the photons incident on the front side of the PV device as possible in the absorber layer. The light trapping techniques may include a front side antireflective coating, multiple window layers, roughening or texturing on the front and/or the back sides, a back side diffuser for scattering the light, and/or a back side reflector for redirecting the light into the interior of the PV device. With such light trapping techniques, more light may be absorbed by the absorber layer for a given amount of incident light, thereby increasing the efficiency of the PV device.