| Autor: |
González JE; São Carlos Institute of Chemistry, University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP, Brazil., Danelon JG; Department of Physics, Federal University of São Carlos, 13565-905 São Carlos, SP, Brazil., Da Silva JLF; São Carlos Institute of Chemistry, University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP, Brazil., Lima MP; Department of Physics, Federal University of São Carlos, 13565-905 São Carlos, SP, Brazil. |
| Jazyk: |
angličtina |
| Zdroj: |
ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2024 Jul 31; Vol. 16 (30), pp. 39251-39265. Date of Electronic Publication: 2024 Jul 18. |
| DOI: |
10.1021/acsami.4c05092 |
| Abstrakt: |
The cubic α-CsPbI 3 phase stands out as one of the most promising perovskite compounds for solar cell applications due to its suitable electronic band gap of 1.7 eV. However, it exhibits structural instability under operational conditions, often transforming into the hexagonal non-perovskite δ-CsPbI 3 phase, which is unsuitable for solar cell applications because of the large band gap (e.g., ∼2.9 eV). Thus, there is growing interest in identifying possible mechanisms for increasing the stability of the cubic α-CsPbI 3 phase. Here, we report a theoretical investigation, based on density functional theory calculations, of the surface passivation of the α-, γ-, and δ-CsPbI 3 (100) surfaces using the C 6 H 4 (NH 3 ) 2 [ p -phenylenediamine (PPD)] and Cs species as passivation agents. Our calculations and analyses corroborate recent experimental findings, showing that PPD passivation effectively stabilizes the cubic α-CsPbI 3 perovskite against the cubic-to-hexagonal phase transition. The PPD molecule exhibits covalent-dominating bonds with the substrate, which makes it more resistant to distortion than the ionic bonds dominant in perovskite bulks. By contrasting these results with the natural Cs passivation, we highlight the superior stability of the PPD passivation, as evidenced by the negative surface formation energies, unlike the positive values observed for the Cs passivation. This disparity is due to the covalent characteristics of the molecule/surface interaction of PPD, as opposed to the purely ionic interaction seen with the Cs passivation. Notably, the PPD passivation maintains the optoelectronic properties of the perovskites because the electronic states derived from the PPD molecules are localized far from the band gap region, which is crucial for optoelectronic applications. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
|
