Bifacial Silicon-Perovskite Tandem Cell for Backside Light Absorption

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Solution Overview

Problem

Conventional tandem solar cells are limited in maximum current value due to the inability to absorb light reflected from the backside of the device, as the lower electrode is formed as the front electrode.

Innovation Solution

A bifacial light-receiving silicon/perovskite tandem solar cell design that includes a silicon lower cell with a first grid electrode on its lower surface, a perovskite upper cell with a thick perovskite absorbing layer, and an interconnecting layer to connect the two cells, allowing for increased light absorption at the backside.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the lower electrode is formed as the front electrode in conventional tandem solar cells, then the device structure is simplified, but light absorption at the backside is prevented, limiting maximum current value

Engineering Contradiction:

Improvedevice structureVSAvoidmaximum current value

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent inverts the conventional electrode configuration by placing the lower electrode on the backside of the silicon lower cell instead of the front surface. This inversion enables the backside to function as a light-receiving surface, allowing reflected light from the environment to be absorbed and converted into electrical current, thereby resolving the contradiction between structural simplicity and current limitation

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If the perovskite absorbing layer thickness is increased to improve light absorption, then photoelectric conversion efficiency increases, but manufacturing precision requirements increase

Engineering Contradiction:

Improvephotoelectric conversion efficiencyVSAvoidperovskite layer thickness control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent specifies a perovskite absorbing layer thickness range of 600-2000 nm, representing a parameter change that optimizes both light absorption and manufacturability. This thickness range is sufficiently thick to absorb light effectively while remaining within controllable manufacturing tolerances for perovskite deposition processes

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 design significantly enhances photoelectric conversion efficiency by increasing light absorption at the backside, resulting in higher current values under various illumination conditions.

Implementation Method 1

a perovskite upper cell configured to include a perovskite absorbing layer with a thickness of greater than 600 nm to 2,000 nm

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

a silicon lower cell configured to include a silicon layer

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP4597584A1Bi-facial light-receiving silicon/perovskite tandem solar cell

Publication Date: 2025.08.06 HANWHA SOLUTIONS CORP

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AI summary

The present disclosure relates to a tandem solar cell and, more specifically, to a bi-facial light-receiving silicon/perovskite tandem solar cell capable of obtaining a remarkably high photoelectric conversion efficiency by having increased light absorption from the bottom part thereof.