HAT-CN Seed Layer for Organic Photovoltaic Crystallinity

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Solution Overview

Problem

Conventional photovoltaic devices, particularly those using organic materials, face challenges in achieving high efficiency and stability due to limitations in crystallinity and charge transport, which affect their power conversion efficiency and fill factor.

Innovation Solution

Incorporating a preferentially hole conducting organic seed layer, such as HAT-CN, to induce an ordered vertical phase of donor molecules, enhancing the crystallinity and charge transport properties of the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional organic photovoltaic devices are used without a preferentially hole conducting organic seed layer, then the device structure is simpler, but the crystallinity and charge transport properties are insufficient, leading to lower power conversion efficiency

Engineering Contradiction:

Improvedevice structure simplicityVSAvoidpower conversion efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

A preferentially hole conducting organic seed layer is deposited beforehand on the substrate before the photoactive layer. This preliminary layer induces an ordered vertical phase of donor molecules in the subsequent photoactive layer, enhancing crystallinity and charge transport properties, thereby resolving the contradiction between structural simplicity and power conversion efficiency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The preferentially hole conducting organic seed layer acts as an intermediary between the substrate and the photoactive layer. It mediates the interaction by providing a template that induces vertical orientation of donor molecules, improving the overall device performance without significantly complicating the manufacturing process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a preferentially hole conducting organic seed layer is incorporated to induce ordered vertical phase, then the crystallinity and charge transport are enhanced, but the device complexity increases

Engineering Contradiction:

Improvecrystallinity and charge transportVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The preferentially hole conducting organic seed layer is applied locally at the interface between the substrate and the photoactive layer. This localized intervention provides the necessary templating effect for vertical orientation of donor molecules without requiring complex modifications throughout the entire device structure, thus balancing reliability improvement with manageable device complexity.

Inventive Principle:

Principle #3Local quality

3Productivity

If HAT-CN is used as a preferentially hole conducting organic seed layer, then the open-circuit voltage, short-circuit current, and fill factor increase, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidmanufacturing process simplicity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

HAT-CN is used as the preferentially hole conducting organic seed layer, changing the material parameter to achieve superior templating effects. This specific material choice enhances open-circuit voltage, short-circuit current, and fill factor, thereby improving power conversion efficiency. The trade-off in manufacturing complexity is accepted as the performance benefits are significant.

Inventive Principle:

Principle #35Parameter changes

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 use of HAT-CN as a seed layer increases the open-circuit voltage, short-circuit current, and fill factor, leading to improved power conversion efficiency and stability of organic photovoltaic devices.

Implementation Method 1

Methodology Applied

Scientific EffectEpitaxy: Epitaxy

Data Source

PatentEP2628198B1Materials for controlling the epitaxial growth of photoactive layers in photovoltaic devices

Publication Date: 2016.06.29 THE RGT UNIV OF MICHIGAN

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AI summary

There is disclosed ultrathin film material templating layers that force the morphology of subsequently grown electrically active thin films have been found to increase the performance of small molecule organic photovoltaic (OPV) cells. There is disclosed electron-transporting material, such as hexaazatriphenylene- hexacarbonitrile (HAT-CN) can be used as a templating material that forces donor materials, such as copper phthalocyanine (CuPc) to assume a vertical-standing morphology when deposited onto its surface on an electrode, such as an indium tin oxide (ITO) electrode. It has been shown that for a device with HAT-CN as the templating buffer layer, the fill factor and short circuit current of CuPc:C60 OPVs were both improved compared with cells lacking the HAT-CN template. This is explained by the reduction of the series resistance due to the improved crystallinity of CuPc grown onto the ITO surface.