Switchable WIPV Device Using Segmented CNT Charge Transport
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Solution Overview
Problem
Conventional building-integrated photovoltaic (BIPV) technologies face a tradeoff between solar-to-electrical power conversion efficiency (PCE) and visible light transmittance (VLT), limiting their application in window-integrated photovoltaic (WIPV) systems, where high PCE is compromised by the need for visible light transparency.
Innovation Solution
A switchable WIPV device is developed using a photothermally modulated mixed-halide perovskite (MHP) absorber layer that reversibly intercalates/de-intercalates molecules, switching between a transparent and opaque state, allowing for high PCE while maintaining visible light transmittance, utilizing a double-layer carbon nanotube (CNT) charge transport layer with a doped and undoped SWCNT structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional photovoltaic materials are used to achieve high power conversion efficiency, then solar-to-electrical power conversion efficiency is improved, but visible light transmittance deteriorates
Solution Approach 1:
The charge transport layer is segmented into multiple layers with different carbon nanotube compositions and doping levels. The first layer contains doped carbon nanotubes for high charge transport, while the second layer contains undoped or lightly-doped carbon nanotubes for optical transparency, allowing the system to achieve both high PCE and high VLT simultaneously
Solution Approach 2:
Different regions of the charge transport layer are assigned different local qualities: the first layer near the electrode has high doping for efficient charge extraction, while the second layer has low doping for optical transparency. This spatial variation in doping concentration allows simultaneous optimization of both electrical performance and optical properties
2Productivity
If the absorber layer is made opaque to maximize light absorption, then power conversion efficiency is improved, but visible light transmittance deteriorates
Solution Approach 1:
The device incorporates a switchable absorber layer that can dynamically change its optical state between transparent and opaque. This dynamic switching capability allows the device to adapt to different operational requirements, achieving high PCE when needed while maintaining high VLT for building integration
Solution Approach 2:
The optical and electrical parameters of the absorber layer are made changeable through molecular intercalation and photothermal modulation. By changing the intercalation state of molecules in the perovskite layer, the device can switch between transparent and opaque states while maintaining photovoltaic functionality
3Device complexity
If a single-layer carbon nanotube structure is used to simplify device structure, then device complexity is reduced, but charge transport performance deteriorates
Solution Approach 1:
The charge transport layer is divided into multiple functional segments (first and second layers) with different carbon nanotube doping levels. This segmentation allows each layer to perform its specialized function optimally while working together to achieve superior overall charge transport performance
Solution Approach 2:
The charge transport layer uses composite material structures combining doped and undoped carbon nanotubes in specific configurations. This composite approach leverages the high conductivity of doped CNTs and the transparency of undoped CNTs to create a multifunctional charge transport layer
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 device achieves a power conversion efficiency exceeding 10% while maintaining high visible light transmittance, overcoming the fundamental tradeoff between PCE and VLT, and demonstrating repeated reversible switching under solar illumination.
Implementation Method 1
the first layer comprises a first carbon nanostructure, and the first layer is configured to transport charges to a charge collecting layer
Implementation Method 2
A switchable WIPV device is developed using a photothermally modulated mixed-halide perovskite (MHP) absorber layer
Implementation Method 3
that reversibly intercalates/de-intercalates molecules, switching between a transparent and opaque state
Implementation Method 4
A switchable WIPV device is developed using a photothermally modulated mixed-halide perovskite (MHP) absorber layer
Data Source
AI summary
The present disclosure relates to a device that includes an active layer and a first charge transport layer, where the first charge transport layer includes a first layer and a second layer, the first layer is in contact with the second layer, the second layer is positioned between the first layer and the active layer, the first layer comprises a first carbon nanostructure, and the second layer includes a second carbon nanostructure.