Cu2O Solar Cell p+ Interface Doping for Lower Carrier Recombination

Solution Overview

Problem

Conventional Cu2O solar cells experience low efficiency due to significant recombination of carriers on the surface of the p-electrode, particularly when light is irradiated from the p-electrode side, leading to a decrease in short circuit current.

Innovation Solution

The implementation of a p+ type region with high concentrations of p-type dopants, such as Si and Ge, in the vicinity of the p-electrode interface, combined with a passivation layer, to suppress recombination and enhance photocarrier generation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If light is irradiated from the p-electrode side in a light transmissive Cu2O solar cell, then the solar cell can utilize light from both sides, but short circuit current becomes small due to carrier recombination on the p-electrode surface

Engineering Contradiction:

Improvelight irradiation from both sidesVSAvoidshort circuit current

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating a p+ type region with high dopant concentration specifically at the p-electrode interface (within 10-100 nm from the interface), while maintaining lower dopant concentration in the bulk p-type light-absorbing layer. This localized modification suppresses carrier recombination at the critical p-electrode surface where light enters from the p-side, thereby improving short circuit current while preserving the dual-sided light irradiation capability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the dopant concentration parameter by introducing a p+ type region with high dopant concentration (10^19 to 10^21 atoms/cm³) at the p-electrode interface, compared to the lower dopant concentration in the bulk layer. This parameter change modifies the electrical properties at the surface to reduce recombination losses, enabling improved performance when light is irradiated from the p-electrode side

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If transparent electrodes are used for both n-electrode and p-electrode to enable light transmissivity, then light can be irradiated from both sides, but efficiency decreases due to carrier recombination on the p-electrode surface

Engineering Contradiction:

Improvelight transmissivity from both sidesVSAvoidconversion efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies local quality by creating a p+ type region with high dopant concentration specifically at the p-electrode interface (within 10-100 nm from the interface), while maintaining lower dopant concentration in the bulk p-type light-absorbing layer. This localized modification suppresses carrier recombination at the critical p-electrode surface where light enters from the p-side, thereby improving short circuit current while preserving the dual-sided light irradiation capability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the dopant concentration parameter by introducing a p+ type region with high dopant concentration (10^19 to 10^21 atoms/cm³) at the p-electrode interface, compared to the lower dopant concentration in the bulk layer. This parameter change modifies the electrical properties at the surface to reduce recombination losses, enabling improved performance when light is irradiated from the p-electrode side

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

This approach significantly increases short circuit current and overall efficiency by preventing carrier recombination, especially when light is incident from the p-electrode side, and improves conversion efficiency by up to 1.7 times compared to configurations without the p+ type region.

Implementation Method 1

Cu2O is a wide-gap semiconductor having a bandgap of 2.1 eV. Cu2O, which includes copper and oxygen existing abundantly on the earth, is a safe and inexpensive material. Therefore, Cu2O is expected to realize a solar cell with high efficiency and low cost.

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

A region from an interface between the p-type light-absorbing layer and the p-electrode to 10 nm to 100 nm from the interface in a direction of the n-type layer is a p+ type region including a p-type dopant

Methodology Applied

Scientific EffectDoping: Dopants

Implementation Method 3

combined with a passivation layer, to suppress recombination and enhance photocarrier generation efficiency

Methodology Applied

Scientific EffectPassivation:

Data Source

PatentUS11810993B2Solar cell, multi-junction solar cell, solar cell module, and photovoltaic power generation system

Publication Date: 2023.11.07 KK TOSHIBA

AI summary

A solar cell of an embodiment includes a p-electrode, a p-type light-absorbing layer directly in contact with the p-electrode, an n-type layer, and an n-electrode. The n-type layer is disposed between the p-type light-absorbing layer and the n-electrode. A region from an interface between the p-type light-absorbing layer and the p-electrode to 10 nm to 100 nm from the interface in a direction of the n-type layer is a p+ type region including a p-type dopant.