High Photon-to-Current Conversion in Solar Cells Based on Light-Absorbing Silver Bismuth Iodide.

ABSTRACT: Here, a lead-free silver bismuth iodide (AgI/BiI3 ) with a crystal structure with space group R3? m is investigated for use in solar cells. Devices based on the silver bismuth iodide deposited from solution on top of TiO2 and the conducting polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) as a hole-transport layer are prepared and the photovoltaic performance is very promising with a power conversion efficiency over 2?%, which is higher than the performance of previously reported bismuth-halide materials for solar cells. Photocurrent generation is observed between 350 and 700?nm, and the maximum external quantum efficiency is around 45?%. The results are compared to solar cells based on the previously reported material AgBi2 I7 , and we observe a clearly higher performance for the devices with the new silver and bismuth iodides composition and different crystal structure. The X-ray diffraction spectrum of the most efficient silver bismuth iodide material shows a hexagonal crystal structure with space group R3? m, and from the light absorption spectrum we obtain an indirect band gap energy of 1.62?eV and a direct band gap energy of 1.85?eV. This report shows the possibility for finding new structures of metal-halides efficient in solar cells and points out new directions for further exploration of lead-free metal-halide solar cells.

SUBMITTER: Zhu H 

PROVIDER: S-EPMC5499729 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature