Influence of PbCl2 content in PbI2 solution of DMF on the absorption, crystal phase, morphology of lead halide thin films and photovoltaic performance in planar perovskite solar cells

• Influence of PbCl2 content on absorption, crystal phase and morphology of thin film.
• Influence of perovskite film thickness on photovoltaic performance of solar cell.
• Lead halide thin film with small sheet-like, porous morphology and low crystallinity.
• Planar solar cell with 300 nm-thick perovskite thin film achieved PCE of 10.12%.

In this paper, the influence of PbCl2 content in PbI2 solution of DMF on the absorption, crystal phase and morphology of lead halide thin films was systematically investigated and the photovoltaic performance of the corresponding planar perovskite solar cells was evaluated. The result revealed that the various thickness lead halide thin film with the small sheet-like, porous morphology and low crystallinity can be produced by adding PbCl2 powder into PbI2 solution of DMF as a precursor solution. The planar perovskite solar cell based on the 300-nm-thick CH3NH3PbI3−xClx thin film by the precursor solution with the mixture of 0.80 M PbI2 and 0.20 M PbCl2 exhibited the optimum photoelectric conversion efficiency of 10.12% along with an open-circuit voltage of 0.93 V, a short-circuit photocurrent density of 15.70 mA cm−2 and a fill factor of 0.69.

The figure showed the surface and cross-sectional SEM images of lead halide thin films using the precursor solutions: (a) 0.80 M PbI2, (b) 0.80 M PbI2+0.20 M PbCl2, (c) 0.80 M PbI2+0.40 M PbCl2, and (d) 0.80 M PbI2+0.60 M PbCl2. With the increase of the PbCl2 content in precursor solution, the size of the lead halide nanosheet decreased and the corresponding thin films gradually turned to be porous with low crystallinity.Figure optionsDownload as PowerPoint slide