An effective approach of vapour assisted morphological tailoring for reducing metal defect sites in lead-free, (CH3NH3)3Bi2I9 bismuth-based perovskite solar cells for improved performance and long-term stability
An effective approach of vapour assisted morphological tailoring for reducing metal defect sites in lead-free, (CH3NH3)3Bi2I9 bismuth-based perovskite solar cells for improved performance and long-term stability
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DOI：
10.1016/j.nanoen.2018.05.003
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发表时间：
2018-07-01
期刊：
影响因子：
17.6
通讯作者：
Durrant, James R.
中科院分区：
文献类型：
--
作者：
Jain, Sagar M.;Phuyal, Dibya;Durrant, James R.
采用气相辅助溶液法(VASP)，通过将BiI3薄膜暴露在CH3NH3I(MAI)蒸气中不同的反应时间，控制、分步合成了(CH3NH3)(3)Bi2I9钙钛矿薄膜，得到了光电性能可调的(CH3NH3)(3)Bi2I9半导体薄膜。在介孔二氧化钛衬底上制备的太阳能电池，无滞后效率高达3.17%，重现性好。良好的性能主要归功于均匀的表面覆盖、改进的化学计量比、降低了块体中的金属含量以及所需的吸收材料的光电性能。此外，使用纯BiI3薄膜制备的太阳能电池在没有MAI曝光的情况下获得了0.34%的功率转换效率。未封装的(CH3NH3)(3)Bi2I9器件的效率仅下降0.1%，但稳定时间长达60天。这种(CH3NH3)(3)Bi2I9钙钛矿薄膜的受控形成突出了VASP技术在优化材料化学计量比、形貌、太阳能电池性能和长期耐用性方面的优势。
We present a controlled, stepwise formation of methylammonium bismuth iodide (CH3NH3)(3)Bi2I9 perovskite films prepared via the vapour assisted solution process (VASP) by exposing BiI3 films to CH3NH3I (MAI) vapours for different reaction times, (CH3NH3)(3)Bi2I9 semiconductor films with tunable optoelectronic properties are obtained. Solar cells prepared on mesoporous TiO2 substrates yielded hysteresis-free efficiencies upto 3.17% with good reproducibility. The good performance is attributed mainly to the homogeneous surface coverage, improved stoichiometry, reduced metallic content in the bulk, and desired optoelectronic properties of the absorbing material. In addition, solar cells prepared using pure BiI3 films without MAI exposure achieved a power conversion efficiency of 0.34%. The non-encapsulated (CH3NH3)(3)Bi2I9 devices were found to be stable for as long as 60 days with only 0.1% drop in efficiency. This controlled formation of (CH3NH3)(3)Bi2I9 perovskite films highlights the benefit of the VASP technique to optimize material stoichiometry, morphology, solar cell performance, and long-term durability.