Composite Photovoltaic Structure for Low Illumination Current
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Solution Overview
Problem
Conventional thin film solar batteries face challenges in achieving high photoelectric conversion efficiency under low illumination conditions, resulting in low induced current despite their high photoelectric conversion efficiency.
Innovation Solution
A composite photovoltaic structure is developed, comprising a transparent substrate with stacked photovoltaic units connected in parallel, featuring specific electron transport, hole transport, and activation layers made of materials like PEI, PEDOT:PSS, P3HT, and PCBM, along with optical hardened layers, to enhance omnidirectional concentration gain and current induction while maintaining a low manufacturing cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single photovoltaic unit is used, then the structure is simple, but the induced current is low under low illumination conditions
Solution Approach 1:
The photovoltaic device is divided into multiple photovoltaic units (first photovoltaic unit and second photovoltaic unit) that are stacked and connected in parallel. Each unit has its own electrode layers and transport layers, allowing them to function independently and contribute to the overall current output, thereby increasing the induced current under low illumination conditions.
Solution Approach 2:
The patent transitions from a single-plane photovoltaic structure to a stacked three-dimensional structure. The first and second photovoltaic units are arranged in the vertical dimension with alternating transparent electrode layers serving as both electrodes and interconnects, enabling light absorption from multiple angles and increasing the photoelectric reaction area without significantly increasing the device footprint.
2Power
If multiple photovoltaic units are stacked to increase photoelectric reaction area, then the induced current improves, but the structure thickness increases
Solution Approach 1:
The patent merges the functions of electrodes and interconnects by using alternating transparent electrode layers (first transparent electrode layer, second transparent electrode layer) that serve dual purposes: as current collectors for individual photovoltaic units and as electrical connections between stacked units. This eliminates the need for separate interconnect layers, thereby reducing overall thickness.
Solution Approach 2:
The transparent electrode layers perform multiple functions simultaneously: they serve as front and back electrodes for different photovoltaic units, act as electrical interconnects between units, and provide structural support. The transport layers (electron transport and hole transport) also serve dual functions of charge separation and charge transport, reducing the need for additional dedicated layers.
3Power
If conventional photovoltaic structure is used, then manufacturing cost is low, but photoelectric conversion efficiency under low illumination is insufficient
Solution Approach 1:
The patent changes the optical and electrical parameters of the photovoltaic structure by introducing alternating transparent electrode layers with different optical properties and arranging photovoltaic units in a stacked configuration. This increases the photoelectric reaction area and improves light trapping, thereby enhancing photoelectric conversion efficiency under low illumination conditions while maintaining compatibility with existing manufacturing processes.
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 composite structure achieves improved omnidirectional concentration gain and efficiently induced current without increasing the structure thickness, meeting the demands of small-size products and reducing manufacturing costs.
Implementation Method 1
a first photovoltaic unit, disposed on the transparent substrate; a second photovoltaic unit, stacked on the first photovoltaic unit, and electrically connected to the first photovoltaic unit in parallel
Implementation Method 2
a top surface layer of the first photovoltaic unit and a bottom surface layer of the second photovoltaic unit are transparent electron transport layers and a bottom surface layer of the first photovoltaic unit and a top surface layer of the second photovoltaic unit are transparent hole transport layers
Data Source
AI summary
A composite photovoltaic structure having the following components is illustrated. A first photovoltaic unit is disposed on a transparent substrate, and electrically connected to a second photovoltaic unit in parallel, and the second photovoltaic unit is stacked on the first photovoltaic unit. The first photovoltaic unit is disposed on a second transparent electrode layer, and a first transparent conductive layer is disposed on a top of the first photovoltaic unit and electrically connected to a first transparent electrode layer, and the second photovoltaic unit is disposed on the first transparent conductive layer. A second transparent conductive layer is disposed on the second photovoltaic unit and is electrically connected to the second transparent electrode layer. Thus, the composite photovoltaic structure has a photoelectric reaction area of a significantly improved omnidirectional concentration gain, an efficiently induced current and a low manufacturing cost, without affecting the whole structure thickness.