Premium
High Photon‐to‐Current Conversion in Solar Cells Based on Light‐Absorbing Silver Bismuth Iodide
Author(s) -
Zhu Huimin,
Pan Mingao,
Johansson Malin B.,
Johansson Erik M. J.
Publication year - 2017
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201700634
Subject(s) - bismuth , band gap , materials science , energy conversion efficiency , iodide , halide , solar cell , photocurrent , optoelectronics , inorganic chemistry , chemistry , metallurgy
Here, a lead‐free silver bismuth iodide (AgI/BiI 3 ) with a crystal structure with space group R 3 ‾ m is investigated for use in solar cells. Devices based on the silver bismuth iodide deposited from solution on top of TiO 2 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 AgBi 2 I 7 , 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 R 3 ‾ 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.