Photovoltaic enhancement of bismuth halide hybrid perovskite by N-methyl pyrrolidone-assisted morphology conversion

Abstract

Low toxicity and highly stable methylammonium bismuth iodide (MBI) ((CH 3 NH 3 ) 3 Bi 2 I 9 ) as a solutionprocessable photovoltaic absorber produces hexagonal non-uniform morphology leading to poor interfacial contacts with the electron and hole transporting layers. Herein, we tuned the morphology of MBI perovskite by bringing in a small amount of N-methyl-2-pyrrolidone (NMP) as a morphology controller into the MBI-DMF solution. The incorporation of various concentrations of NMP into the precursor solution was found to control the rate of crystallization. An optimal low concentration of 2.5% NMP added to the MBI-DMF precursor solution showed a 50% enhancement in short-circuit current (J sc ). The device showed power conversion efficiencies up to 0.31% with high reproducibility. Moreover, the devices were quite stable when exposed to an ambient atmosphere (relative humidity of 50-60%) for 30 days. † Electronic supplementary information (ESI) available: Experimental procedure, top surface SEM images, UV-vis, J-V curve are provided. See rsc.li/rsc-advances 9456 | RSC Adv., 2017, 7, 9456-9460 This journal isFig. 3 (a) Average J-V curves, (b) IPCE spectra, (c) J sc and (d) PCE histogram plot of devices containing MBI perovskite without and with different concentration of NMP. 9458 | RSC Adv., 2017, 7, 9456-9460 This journal is

Potential Substitutes for Replacement of Lead in Perovskite Solar Cells: A Review

“…The morphology of (MA) 3 Bi 2 I 9 perovskite film can also be enhanced by incorporating a small amount of N‐methyl‐2 pyrrolidone (NMP) into the MBI‐DMF solution. The addition of various concentration of NMP into the precursor solution not only controls the rate of crystallization but also enhanced SPCE to a value of 0.31% and stability for 30 d in a relative humidity of 50–60% . The optical measurement of solution‐processed perovskite film (MA) 3 Bi 2 I 9 fabricated by spin‐coating process showed a strong absorption band around 500 nm on further heating.…”

“…Table 9 shows some photovoltaic parameters of bismuth‐based perovskites. Figure shows the SEM images of (MA) 3 Bi 2 I 9 without and with different concentration of NMP additives …”

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