Materials for sustainable tandem solar cells with maximum conversion efficiency

Fraunhofer Lighthouse Project

Perovskite silicon tandem solar cell based on a silicon solar cell, developed within the Fraunhofer Lighthouse Project ”MaNiTU” – Materials for sustainable tandem solar cells with highest conversion efficiency.
© Fraunhofer ISE
Perovskite silicon tandem solar cell based on a silicon solar cell, developed within the Fraunhofer Lighthouse Project ”MaNiTU” – Materials for sustainable tandem solar cells with highest conversion efficiency.
Das 7., 9., 12. und 13. Ziel für nachhaltige Entwicklung der UN

Challenge

In order for photovoltaics to be able to reliably ensure the power supply – e.g. for energy-autonomous buildings, electric cars or other products – at an acceptable cost, solar cells are necessary which are as efficient as possible and which require correspondingly less material and surface area than conventional modules. For physical reasons, however, the efficiency of established silicon solar cells cannot be increased arbitrarily. 

Solution 

In a joint project, 5 Fraunhofer institutes are therefore working on the development of perovskite silicon tandem solar cells with which efficiencies of more than 35 percent can be achieved. Within this context, both equipment technology and manufacturing processes are being further developed and adapted. The focus here is on the production of large-area selective charge-carrier layers, buffer and passivation layers, and transparent conductive oxides (TCOs) by means of sputtering processes. For the development of the electron contact system, a novel high-rate SALD hybrid facility is being utilized. Within the framework of the project, indium-based TCOs were optimized and the processes were transferred to a large-area sputtering facility. In addition, a novel hybrid system setup consisting of atomic layer deposition and evaporator unit was assembled and the first combination layers were produced. Furthermore, optical models for the determination of dispersion data were developed in order to simulate cell performance.

Added value

The Fraunhofer IST has amassed extensive experience in the field of thin-film and silicon technology for photovoltaics. As a result, it is possible, amongst other things, to ensure that the various layers are adapted both electronically and optically – i.e. with low absorption – to the absorbers; in this case, silicon and perovskite. In addition to its expertise in layer and process development, the Fraunhofer IST offers customer-specific services in the field of sustainability management and life cycle engineering.

Insights into the project

Measured ellipsometry, photometry, and X-ray reflectance spectra of a C60/SnO<sub>2</sub> film system and determination of dispersion data.
© Fraunhofer IST
Measured ellipsometry, photometry, and X-ray reflectance spectra of a C60/SnO2 film system and determination of dispersion data.
FHR Star 400x300 SALD coating system for thermal local atomic layer deposition.
© Fraunhofer IST
Novel system for spatial atomic layer deposition (SALD) with hybrid area for other deposition technologies. Maximum substrate dimensions: 400 mm x 300 mm.

Further information

 

From research

Sustainable highly efficient perovskite silicon tandem solar cells

 

Publication

Volker Sittinger, Patricia S. C. Schulze, Christoph Messmer, Andreas Pflug, and Jan Christoph Goldschmidt.

Complex refractive indices of Spiro-TTB and C60 for optical analysis of perovskite silicon tandem solar cells.

Optics Express Vol. 30, Issue 21, pp. 37957-37970 (2022)

 

Website of the project MaNiTU

Click here to visit the official website of the Fraunhofer lighthouse project:

Our focus and expertise

 

Diamond-based systems and CleanTech

Layers for photovoltaics

 

Optical and electrical systems

Transparent conductive oxides

 

Sustainability management and LCE

Life Cycle Engineering

 

Chemical Vapor Deposition (CVD technology)

Atomic layer deposition

We offer solutions for your applications

 

Industry solutions

Energy