Role of Tin Chloride in Tin-Rich Mixed-Halide Perovskites Applied as Mesoscopic Solar Cells with a Carbon Counter Electrode
Journal
ACS Energy Letters
Journal Volume
1
Journal Issue
6
Pages
1086
Date Issued
2016-12-09
Author(s)
Tsai, Cheng Min
Wu, Hui Ping
Chang, Sun Tang
Huang, Chi Feng
Wang, Chia Hsin
Narra, Sudhakar
Yang, Yaw Wen
Hung, Chen Hsiung
Diau, Eric Wei Guang
Abstract
We report the synthesis and characterization of alloyed Sn-Pb methylammonium mixed-halide perovskites (CH3NH3SnyPb1-yI3-xClx) to extend light harvesting toward the near-infrared region for carbon-based mesoscopic solar cells free of organic hole-transport layers. The proportions of Sn in perovskites are well-controlled by mixing tin chloride (SnCl2) and lead iodide (PbI2) in varied stoichiometric ratios (y = 0-1). SnCl2 plays a key role in modifying the lattice structure of the perovskite, showing anomalous optical and optoelectronic properties; upon increasing the concentration of SnCl2, the variation of the band gap and band energy differed from those of the SnI2 precursor. The CH3NH3SnyPb1-yI3-xClx devices showed enhanced photovoltaic performance upon increasing the proportion of SnCl2 until y = 0.75, consistent with the corresponding potential energy levels. The photovoltaic performance was further improved upon adding 30 mol % tin fluoride (SnF2) with device configuration FTO/TiO2/Al2O3/NiO/C, producing the best power conversion efficiency, 5.13%, with great reproducibility and intrinsic stability.
Type
journal article