Efficiency enhancement of Si nanostructure hybrid solar cells by optimizing non-radiative energy transfer from Si quantum dots

Abstract

Non-radiative energy transfer (NRET) from silicon quantum dots (SiQDs) terminated with ligands is an effective way to improve solar cell efficiency. The NRET effect can be enhanced by minimizing the distance between SiQDs and the solar cell surface. SiQDs were inserted between poly (3,4-ethylene dioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) and Si nanostructures of hybrid heterojunction solar cells. To clarify dependence on ligand length, three different ligands of different lengths were investigated. 1-octene, which has the shortest ligand length, showed the greatest enhancement of NRET, resulting in the highest solar cell efficiency. The non-radiative energy transfer (NRET) effect in Si quantum dots (SiQDs) can be enhanced by shortening the ligand length, resulting in enhanced short circuit current, thus significantly improving the energy conversion efficiency of solar cells. • High-efficiency hybrid solar cells were fabricated by inserting SiQDs into hybrid solar cell with Si nanotips and PEDOT:PSS. • Non-radiative energy transfer from SiQDs terminated with ligands effectively enhanced conversion efficiency of solar cells. • SiQDs with shorter ligands had a higher conversion efficiency. • The highest conversion efficiency of 12.4% was given by hybrid solar cells with 1-octene terminated SiQDs.