Improved film morphology of (CH3NH3)3Bi2I9 via cation displacement approach for lead-free perovskite solar cells
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Methylammonium bismuth iodide (MA3Bi2I9) has been recently investigated as a light absorber in lead-free perovskite solar cells. However, the MA3Bi2I9 film fabricated via conventional one-step spin coating methods usually has poor surface morphology, limiting the device performance. Herein, a cation displacement approach was employed for the fabrication of MA3Bi2I9 film, where (CH3CH2CH2NH3)3Bi2I9 (PA3Bi2I9) film was first deposited from a solution containing CH3CH2CH2NH3I and BiI3 and then transformed into MA3Bi2I9 film in a methylamine atmosphere. With the technique, the MA3Bi2I9 film was realized with smooth, uniform, and compact surface morphology. Using the MA3Bi2I9 film as a light absorber, a mesoporous photovoltaic device was fabricated with a power conversion efficiency of 0.33%, which is about two times higher than the value (0.15%) obtained for the one-step spin coating MA3Bi2I9 device. Moreover, the facile film fabrication strategy utilized in this work paves the way for high reproducibility of lead-free organic–inorganic halide films and devices.
This work was supported by the National Nature Science Foundation of China (Grant Nos. 61874123, 21572235), the National Key R and D Program of China (Grant No. 2018YFA0208501), and the “Strategic Priority Research Program” of Chinese Academy of Sciences (Grant No. XDA09020000).
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Conflict of interest
The authors declare they have no conflict of interest.
- 8.NREL, Best Research-Cell Efficiences chart; www.nrel.gov/pv/assets/images/efficiency-chart20180716.jpg
- 15.Hoye RLZ, Brandt RE, Osherov A, Stevanovic V, Stranks SD, Wilson MWB, Kim H, Akey AJ, Perkins JD, Kurchin RC, Poindexter JR, Wang EN, Bawendi MG, Bulovic V, Buonassisi T (2016) Methylammonium bismuth iodide as a lead-free, stable hybrid organic-inorganic solar absorber. Chem Eur J 22(8):2605–2610CrossRefGoogle Scholar
- 21.Lehner AJ, Fabini DH, Evans HA, Hebert CA, Smock SR, Hu J, Wang H, Zwanziger JW, Chabinyc ML, Seshadri R (2015) Crystal and electronic structures of complex bismuth iodides A3Bi2I9 (A = K, Rb, Cs) related to perovskite: aiding the rational design of photovoltaics. Chem Mater 27(20):7137–7148CrossRefGoogle Scholar
- 22.Jain SM, Phuyal D, Davies ML, Li M, Philippe B, Castro CD, Qiu Z, Kim J, Watson T, Tsoi WC, Karis O, Rensmo H, Boschloo G, Edvinsson T, Durran JR (2018) 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. Nano Energy 49:614–624CrossRefGoogle Scholar