Singlet Fission Interlayer for Silicon Solar Cell Efficiency

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Solution Overview

Problem

Silicon solar cells are approaching their thermodynamic limit, leading to suboptimal harvesting of the solar spectrum due to excess energy loss from photons with energies above the bandgap, which limits their power conversion efficiency and increases costs.

Innovation Solution

A system comprising a substrate with an inorganic semiconductor and an interlayer of transition metal oxide, oxynitride, or nitride is used, with a layer that undergoes singlet exciton fission when exposed to electromagnetic radiation, allowing for energy transfer and charge separation to enhance efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If silicon solar cells are used to harvest solar energy, then power conversion efficiency is improved, but the thermodynamic limit of 29.1% is reached, preventing further efficiency improvements

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidexcess energy loss from photons

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent changes the energy state parameters of photons by introducing singlet exciton fission in the organic layer, which converts high-energy photons into multiple triplet excitons with lower energy, enabling multi-exciton generation and overcoming the single electron-hole pair limitation of conventional silicon solar cells

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces an organic interlayer with singlet fission capability as an intermediary between the silicon substrate and the incoming photons. This interlayer mediates the energy transfer process by absorbing photons, undergoing singlet exciton fission to generate triplet excitons, and then transferring these excitons to the silicon substrate, thereby enabling efficient harvesting of high-energy photons without exceeding the thermodynamic limit

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If photons with energies above the bandgap are absorbed, then more solar spectrum is harvested, but excess energy is lost during thermalization to the band edge

Engineering Contradiction:

Improvesolar spectrum harvestingVSAvoidexcess energy loss during thermalization

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent changes the energy distribution parameters by using singlet exciton fission to convert high-energy photons into multiple lower-energy triplet excitons, which then transfer to silicon. This parameter transformation allows the system to utilize the full solar spectrum while minimizing thermalization losses, as each high-energy photon generates multiple electron-hole pairs instead of losing excess energy as heat

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the previously harmful excess energy (which caused thermalization losses) into a beneficial resource by using singlet exciton fission to generate multiple triplet excitons from high-energy photons. The excess energy that would have been lost as heat is now utilized to create additional excitons, transforming the waste energy into useful electrical output

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 configuration enables increased power conversion efficiency by facilitating triplet exciton transfer and electric field passivation, potentially doubling photocurrent and improving surface passivation, thus overcoming the Shockley-Queisser limit.

Implementation Method 1

the layer comprises a material that undergoes singlet exciton fission when exposed to electromagnetic radiation

Methodology Applied

Scientific EffectSinglet exciton fission:

Implementation Method 2

enables increased power conversion efficiency by facilitating triplet exciton transfer

Methodology Applied

Scientific EffectTriplet exciton transfer:

Implementation Method 3

enables increased power conversion efficiency by facilitating triplet exciton transfer and electric field passivation

Methodology Applied

Scientific EffectElectric field passivation:

Data Source

PatentUS11362293B2Interlayers and associated systems, devices, and methods

Publication Date: 2022.06.14 MASSACHUSETTS INST OF TECH

AI summary

Embodiments related to interlayers (e.g., interlayers comprising a transition metal oxide, a transition metal oxynitride, and/or a transition metal nitride) and associated systems, devices (e.g., photovoltaic devices), and methods are disclosed. In some embodiments, a system for exciton transfer includes a substrate including an inorganic semiconductor. An interlayer may be disposed on the substrate, and a layer including a material that undergoes singlet exciton fission when exposed to electromagnetic radiation may be disposed on the interlayer. The interlayer may be disposed between the substrate and the layer. In some embodiments, a method for manufacturing a system for exciton transfer involves depositing an interlayer onto a substrate that includes an inorganic semiconductor. The method may also include depositing a layer including a material that undergoes singlet exciton fission when exposed to electromagnetic radiation onto the interlayer.