# Laminating Fabrication of Bifacial Organic-Inorganic Perovskite Solar Cells

Authors: Yujing Yang; Yue Zhu; Xiaoxiao Wang; Qi Song; Chao Ji; Huimin Zhang; Zhiqun He; Chunjun Liang
Journal: International Journal of Photoenergy
 (2020)

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## Abstract

Bifacial solar cells based on organic-inorganic perovskite are fabricated with a laminating process. The structure of the devices is ITO/SnO2/CH3NH3PbI3/NiOx/ITO, in which both electrodes are the transparent ITO layer. Therefore, the device can receive light from both sides. By laminating the two half-devices, ITO/SnO2/CH3NH3PbI3 and CH3NH3PbI3/NiOx/ITO, at high temperature with pressure, the merging of the middle perovskite layers is enhanced. The optimized bifacial PSCs show a Voc of 0.85 V, FF of 0.58, Jsc of 17.53 mA/cm2, and PCE of 8.47%. The photovoltaic performance varies when the light is illuminated from different sides of the bifacial PSCs. With illumination from the SnO2 side, the Voc and Jsc of the PSCs are apparently higher than those from the NiOx side, suggesting more severe electron-hole recombination at the NiOx/perovskite interface than at the SnO2/perovskite interface.


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## Body

## 1. Conclusion

In conclusion, the bifacial PSCs with the structure of ITO/SnO2/CH3NH3PbI3/NiOx/ITO are fabricated. At the constant pressure of 42 kPa and at the elevated temperature of 200°C, the merging of the perovskite layers is enhanced, leading to an improved contact area and Jsc. The optimized bifacial PSCs show a Voc of 0.85 V, FF of 0.58, Jsc of 17.53 mA/cm2, and PCE of 8.47%. The photovoltaic performance is different when the light is illuminated from different sides of the bifacial PSCs. With illumination from the SnO2 side, the Voc and Jsc of the PSCs are apparently larger than those from the NiOx side. The result suggests more severe electron-hole recombination at the NiOx/perovskite interface than at the SnO2/perovskite interface.Figure 1
Schematic diagram of PSCs under illumination: (a) conventional PSCs; (b) bifacial PSCs.
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(b)Figure 2
Device structures: (a) schematic diagram of a bifacial PSC with ITO/SnO2/CH3NH3PbI3/NiOx/ITO configuration; (b) energy band diagram of a bifacial PSC.
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(b)Figure 3
Flow chart of bifacial PSCs: (a) deposition perovskite film on the SnO2 and NiOx substrate, respectively; (b) lamination of the substrates together with pressure at 200°C for 15 min; (c) final device with perovskite films merging together; (d) photography of the devices.
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(d)Figure 4
Surface topography of the perovskite layer and the merging of the intermediate perovskite layers during the lamination process: (a) AFM surface topography of the perovskite layer on the SnO2 substrate; (b) AFM surface topography of the perovskite layer on the NiOx substrate; (c) schematics showing the perovskite films before lamination with pressure and heating; (d) schematics showing the middle perovskite layers merging together after lamination.
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(d)Figure 5
The dependence of the device performance on the applied temperature during the lamination.Figure 6
Effect of pressure on device performance.Figure 7
The different performances of the bifacial PSCs with illumination from different sides: (a) current-voltage characteristics of the PSCs; (b) statistics of the photovoltaic parameters in multiple devices.
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(b)Figure 8
The absorption spectra and the light intensity distribution in the bifacial PSCs: (a) absorption spectra; (b) light intensity distribution with illumination from the SnO2 and NiOx sides, respectively. The light intensity profile in the perovskite also reflects the photogenerated carrier distribution.
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*Source: 5039192-2020-01-02.xml*