The effect of spacer cations on optoelectronic properties of two-dimensional perovskite based on first-principles calculations

Compared with traditional RP and DJ phase two-dimensional perovskites, ACI-phase perovskite solar cells achieved relatively higher power conversion efficiency up to 19.3%, which has the different electronic structures on tuning the band gap. Herein, the electronic properties of the ACI and RP phase perovskites were systemati-cally studied. We found that the bandgap modulation range of GA, BA and PEA perovskites all gradually decrease with increasing layer number n. Interestingly, compared with RP phase perovskites, the ACI perovskite with GA spacer cations has a smaller bandgap modulation range when the layer numbers are the same. Due to the alternative arrangement of GA and MA cations, the structure of ACI perovskite has the smallest interlayer spacing and the equatorial Pb-I-Pb angles closer to 180 degrees Therefore, Strong anti-bonding coupling between Pb-I of ACI perovskite will increase the valence band maximum and thus decrease its band gap. The size and ligand of different spacer cations affect the physical properties of two-dimensional perovskites evidently. This theoretical investigation will offer beneficial strategies for choosing spacer cations and designing more stable perovskite devices suitable for photovoltaic applications.

Automated summary

Compared with traditional RP and DJ phase two-dimensional perovskites, ACI-phase perovskite solar cells achieved higher power conversion efficiency and have different electronic structures and band gap tuning.