Compound Charge Transport Layer for Transparent Organic Solar Cells

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Solution Overview

Problem

The challenge lies in developing transparent solar cells that can efficiently convert light into electricity while maintaining transparency, as conventional photovoltaic devices face limitations due to mechanical inflexibility, high module costs, and band-like absorption of inorganic semiconductors, which restrict their integration into transparent applications like window glass.

Innovation Solution

The development of visibly transparent organic photovoltaic devices using photoactive compounds that absorb light more strongly in near-infrared and ultraviolet regions and less in the visible region, incorporating metal-oxide interlayers and charge transport layers to decouple energy levels and enhance charge selectivity, allowing for the use of dissimilar organic materials and improving transparency and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If inorganic semiconductors are used in photovoltaic devices, then power conversion efficiency is improved, but transparency is worsened due to band-like absorption in the visible spectrum

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidtransparency

Core Design Contradiction:

ProductivityVSIllumination intensity

Solution Approach 1:

The patent changes the fundamental material parameter from inorganic to organic semiconductors, which have different absorption characteristics. Organic semiconductors exhibit structured absorption spectra with distinct minima and maxima rather than band-like absorption, allowing selection of materials that absorb in UV and NIR regions while remaining transparent in the visible region (450-650 nm).

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures including metal-oxide interlayers (such as MoO3, WO3, NiO) combined with organic charge transport layers. These composite structures enable independent optimization of energy level alignment and optical properties, achieving both high power conversion efficiency and transparency through the strategic combination of materials with complementary properties.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional charge transport layers are used, then charge transport is improved, but energy level alignment with dissimilar organic materials is worsened

Engineering Contradiction:

Improvecharge transportVSAvoidcompatibility with dissimilar organic materials

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces metal-oxide interlayers as intermediary components between the electrode and organic charge transport layer. These metal-oxide layers serve as energy level mediators that can be independently tuned to match the HOMO or LUMO levels of various organic materials, enabling efficient charge extraction while maintaining compatibility with dissimilar organic photoactive compounds and charge transport materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If photoactive materials with strong visible absorption are used, then power conversion efficiency is improved, but transparency is worsened

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidvisible transparency

Core Design Contradiction:

ProductivityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by selecting photoactive organic materials with specifically tailored absorption characteristics that are strong in UV and NIR regions but weak in the visible region. This localized absorption strategy allows the material to efficiently convert non-visible solar radiation into electricity while maintaining high visible transparency for window glass applications.

Inventive Principle:

Principle #3Local quality

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 approach enables the creation of transparent solar cells with improved mechanical flexibility and reduced costs, allowing for efficient energy conversion while maintaining transparency, and decouples energy levels from the built-in potential, enabling higher open-circuit voltage and power conversion efficiency.

Implementation Method 1

Photovoltaic devices are commonly employed to convert light into electricity by using the photovoltaic effect, in which absorbed light causes the excitation of an electron or other charge carrier to a higher-energy state.

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

decouples energy levels from the built-in potential, enabling higher open-circuit voltage and power conversion efficiency

Methodology Applied

Scientific EffectEnergy level decoupling:

Data Source

PatentUS11839095B2Compound charge transport layer for organic photovoltaic devices

Publication Date: 2023.12.05 UBIQUITOUS ENERGY INC

AI summary

Organic photovoltaic devices with compound charge transport layers are described herein. One such device includes a substrate, a first electrode coupled to the substrate, a second electrode disposed above the first electrode, and photoactive layers disposed between the first electrode and the second electrode. The device further includes a compound charge transport layer disposed between the photoactive layers and either the first electrode or the second electrode. The compound charge transport layer includes a charge transport layer and a metal-oxide interlayer disposed between the charge transport layer and the photoactive layers. The charge transport layer may be a hole transport layer or an electron transport layer.