Hydrogen in solar-grade p-type silicon: dominant complexes and solar cell efficiency (HydSil) (completed)

This project focuses on improving the efficiency of silicon-based solar cells by studying the mechanisms of defects which are responsible for degradation under illumination, causing the so-called Light-Induced Degradation (LID) effect. These defects will be investigated in connection with hydrogen which is already commonly introduced during the fabrication of solar cell.

About the project


The photovoltaic market is dominated by solar cells based on mc-Si, and it is expected that Si will continue to dominate in the years to come. Huge efforts are put down in research related to improving and optimizing such silicon based photovoltaics.

Practically all earlier solar cells based on p-type Si suffered considerable degradation under illumination. The degradation has been attributed to light-induced dissociation of the B-Fe pair. Metallic impurities are still common for modern mc-Si, and the problem of light-induced degradation is still very serious. In contrast, high- quality single-crystalline Si (sc-Si) is nowadays virtually free of metallic impurities. However, despite the progress, the light-induced degradation of p-type sc-Si cells still persists, although due to a different mechanism. This degradation is now widely believed to be caused by carrier recombination at the B-02 complex.

H is an important impurity in Si, not only because of its presene in Si, but also because of its ability to passivate dangling bonds of the defects, and can therefore potentially be used beneficially. Moreover, H can beintroduced in Si during multiple technological steps of solar cell fabrication. The role of hydrogen is particularly important in the HIT solar cells, where a thin layer of hydrogenated amorphous Si (a-Si:H) is used.

We will

  1. address the issues of hydrogen complexes in solar-grade p-type Si, particularly with boron and metallic impurities in both se-Si and mc-Si material
  2. perform predictive simulations of the effect of these complexes on the overall conversion efficiency of solar cells

Objectives

The objective of this project is to investigate

  • the properties of hydrogen complexes in solar graded p-type Si, particularly with boron and metallic impurities in both sc-Si and mc-Si material
  • predictive simulations of the effect of these complexes on the overall conversion efficiency of solar cells. The overall objective of this project is aimed at increase of solar cell efficiency and improvement of labor competence via PhD education

Financing

The Research Council of Norway

Published Feb. 17, 2011 3:33 PM - Last modified Feb. 22, 2019 7:53 AM

Contact

Project leader: Edouard Monakhov