Latest Science: Cationic reactivity inhibits perovskite degradation

2025/8/28 11:22:36 admin 阅读 165【次】

While perovskite solar modules (PSMs) boast excellent power conversion efficiencies (PCEs), long-term operational stability remains a challenge. Degradation due to external factors such as moisture, heat, and sunlight persists. In particular, thermal and photoinduced phase degradation of three-dimensional perovskites limits PSM stability.

Based on this, researchers including Yong Ding of North China Electric Power University, Professor Mohammad Khaja Nazeeruddin of the Federal Institute of Technology in Lausanne, Professor Paul J. Dyson, and Kangning Zhao, along with Researcher Wang Rui of Westlake University and Jiang Sheng of Changzhou Shengsheng Precision Equipment Co., Ltd., improved the quality and photovoltaic (PV) performance of perovskite thin films by introducing an additive into the perovskite precursor solution (PPS). They selected [Dmei]Cl as the additive. Upon incorporation of [Dmei]Cl into the PPS, the [Dmei]+ cation signal disappeared as observed by nuclear magnetic resonance (NMR) spectroscopy. The resulting PSMs achieved a certified PCE of 23.2% over an open area of 27.2 cm². The encapsulated PSM retained 87.0% of its initial PCE after 1900 hours of maximum power point tracking at 85°C, 85% relative humidity, and 1.0-sun illumination.
The results indicate that the in situ formation of [MTTZ]+ cations increases the formation energy of iodine vacancies and the migration energy barrier for iodide and cesium ions, suppressing non-radiative recombination, thermal decomposition, and phase separation. The in situ formation of [MTTZ]+ and [DMA]+ cations was confirmed by NMR spectroscopy, and their presence in the perovskite film was further revealed by XRD and STEM analysis.

Fig. 1. Reaction mechanism, morphology, elemental mapping, and crystal lattice of the [Dmei]Cl perovskite films. (A) Proposed mechanism for the in situ formation of the [MTTZ]+ and [DMA]+ cations. (B) Secondary electron image of the [Dmei]Cl film obtained using HIM. The red circle highlights 1D grains.(C) HIM-SIMS elemental mapping of 35Cl in blue and 127I in cyan. (D) Overlap elemental mapping of 133Cs in green and 208Pb in red. (E) High-resolution transmission electron microscopy (TEM) image of the [Dmei]Cl film. (F) Expansion of the pink dashed square in (E) corresponding to 1D perovskite. (G) Expansion of the green dashed square in (E) corresponding to 3D perovskite in the bulk region (left), and the corresponding interplanar spacing (right). (H) Expansion of the red dashed square in (E) corresponding to 3D perovskite in the edge region (left), and the corresponding interplanar spacing (right).

Fig. 2. In situ conductivity and local crystal structure of the perovskite films during thermal aging. The evolution of c-AFM maps at different heating intervals for the (A) control and (B) [Dmei]Cl films. (C) Comparison between experimental and calculated differential PDF spectra of fresh perovskite films. The contribution of the perovskite and SnO2 phases is highlighted in pink and orange, respectively, according to the simulation pattern of SnO2 and Cs0.05MA0.05FA0.9PbI3 perovskite. (D) Normalized Pb LIII edge x-ray absorption coefficient [m(E)] for the control and [Dmei]Cl films without and with thermal aging at 100°C for 24 hours. XAS spectra and fitting in R-space for (E) the control film before and after aging, and (F) the [Dmei]Cl film before and after aging. The dashed lines represent the experimentally determined data, and the solid blue lines correspond to simulated data. (G) The simulated Pb–I bond lengths and (H) Pb–I coordination numbers of the control and [Dmei]Cl films before and after aging.

Fig. 3. Light stress on the PL peak intensity and position of the perovskite films. In situ PL intensity maps on the same region of the (A) control and (B) [Dmei]Cl films over time under white-light illumination with an intensity of 450 mW cm−2 (equivalent to 4.5 suns). The corresponding PL peak position of the (C) control and (D) [Dmei]Cl films. Scale bars, 2 mm

Fig. 4. PV performance and long-term operational stability of PSMs. (A) The certified current-voltage (I-V) curves from forward and reverse scans of a [Dmei]Cl PSM with an aperture area of 27.2 cm2 from NPVM, China. (B) The certified stabilized efficiency of a [Dmei]Cl PSM. The inset in (B) is the relative spectral responsivity curve.(C) ISOS-L-1 stability protocols of the encapsulated PSMs measured under MPP tracking and continuous light irradiation with a white light-emitting diode (LED) lamp,100 mW·cm2 under ambient conditions. The initial PCE of the control and [Dmei]Cl PSMs are 21.3 and 23.1%, respectively. (D) The encapsulated PSMs measured under MPP tracking and continuous light irradiation with a white LED lamp,100 mW·cm2 at 85°C and 85% RH. The initial PCE of the control and [Dmei]Cl PSMs are 21.3 and 23.2%, respectively. (E) Schematic showing the roles of [MTTZ]+ and [DMA]+ in the 3D perovskite matrix.

本文来源：DOI: 10.1126/science.ado6619
https://www.science.org/doi/10.1126/science.ado6619

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Latest Science: Cationic reactivity inhibits perovskite degradation

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