Open AccessTemplate‐Assisted Formation of High‐Quality α‐Phase HC(NH 2 ) 2 PbI 3 Perovskite Solar Cells
Author(s) -
Shi Pengju,
Ding Yong,
Ren Yingke,
Shi Xiaoqiang,
Arain Zulqarnain,
Liu Cheng,
Liu Xuepeng,
Cai Molang,
Cao Guozhong,
Nazeeruddin Mohammad Khaja,
Dai Songyuan
Publication year - 2019
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201901591
Subject(s) - materials science , formamidinium , photoluminescence , perovskite (structure) , energy conversion efficiency , annealing (glass) , halide , chemical engineering , phase (matter) , photovoltaic system , absorption edge , analytical chemistry (journal) , optoelectronics , band gap , composite material , chemistry , inorganic chemistry , ecology , organic chemistry , chromatography , engineering , biology
Formamidinium (FA) lead halide (α‐FAPbI 3 ) perovskites are promising materials for photovoltaic applications because of their excellent light harvesting capability (absorption edge 840 nm) and long carrier diffusion length. However, it is extremely difficult to prepare a pure α‐FAPbI 3 phase because of its easy transformation into a nondesirable δ‐FAPbI 3 phase. In the present study, a “perovskite” template (MAPbI 3 ‐FAI‐PbI 2 ‐DMSO) structure is used to avoid and suppress the formation of δ‐FAPbI 3 phases. The perovskite structure is formed via postdeposition involving the treatment of colloidal MAI‐PbI 2 ‐DMSO film with FAI before annealing. In situ X‐ray diffraction in vacuum shows no detectable δ‐FAPbI 3 phase during the whole synthesis process when the sample is annealed from 100 to 180 °C. This method is found to reduce defects at grain boundaries and enhance the film quality as determined by means of photoluminescence mapping and Kelvin probe force microscopy. The perovskite solar cells (PSCs) fabricated by this method demonstrate a much‐enhanced short‐circuit current density ( J sc ) of 24.99 mA cm −2 and a power conversion efficiency (PCE) of 21.24%, which is the highest efficiency reported for pure FAPbI 3 , with great stability under 800 h of thermal ageing and 500 h of light soaking in nitrogen.