Thermal Stability of Perovskite Solar Cells

Perovskite solar cells based on organic–inorganic lead halide absorbers have achieved remarkable power conversion efficiencies but are hindered by thermal instability under operating conditions. Elevated temperatures can induce chemical decomposition of the perovskite lattice, phase transitions between tetragonal and cubic polymorphs, volatilisation of organic cations and growth of non-perovskite phases. These processes compromise device performance by generating trap states, pinhole defects and interfacial delamination. Strategies to enhance thermal resilience include compositional engineering of A-site cations, incorporation of low-dimensional perovskite layers, surface passivation and robust encapsulation. A mechanistic understanding of heat-driven degradation pathways and the kinetics of structural transformations is essential to design perovskite formulations and device architectures capable of stable long-term operation in real-world climates.

Research from Nature Portfolio

Investigations using non-ambient X-ray diffraction combined with Knudsen effusion techniques have demonstrated that all methylammonium lead halide compositions decompose into lead halide solids and gaseous methylamine plus hydrogen halide at temperatures as low as 60 °C. Studies employing in situ grazing-incidence wide-angle X-ray diffraction and high-resolution X-ray photoelectron spectroscopy under inert atmosphere have mapped the emergence of intermediate phases and the evolution of CH₃I, NH₃ and PbI₂ upon brief exposure to 100 °C or prolonged heating at 80 °C. First-principles thermodynamic calculations have further elucidated the driving forces underpinning cation-driven instability, linking the aqueous solubility of decomposition products to moisture-induced degradation and guiding the search for alternative stable perovskite compositions.

Thermal Stability of Perovskite Solar Cells publication trend

The graph below shows the total number of articles in thermal stability of perovskite solar cells across all publications each year (not limited to Nature Index journals).

Technical terms

Thermal decomposition: Breakdown of a material’s chemical structure under heat, releasing volatile products.

Grazing-incidence wide-angle X-ray diffraction (GIWAXD): A surface-sensitive technique for characterising thin-film crystallography at shallow incident angles.

Knudsen effusion mass spectrometry (KEMS): A method to analyse vapours emitted by a material heated in a controlled vacuum cell.

Activation energy: The minimum energy barrier that must be overcome for a chemical reaction to proceed.

Phase transition: A change in the crystal structure of a material induced by temperature or pressure.

References

1. On the Thermal and Thermodynamic (In)Stability of Methylammonium Lead Halide Perovskites. Scientific Reports (2016).
2. Investigation of Thermally Induced Degradation in CH3NH3PbI3 Perovskite Solar Cells using In-situ Synchrotron Radiation Analysis. Scientific Reports (2017).
3. Thermodynamic origin of instability in hybrid halide perovskites. Scientific Reports (2016).
4. Thermochemical Stability of Hybrid Halide Perovskites. ACS Energy Letters (2019).
5. Thermodynamic and Kinetic Aspects of Formamidinium Lead Iodide Thermal Decomposition. The Journal of Physical Chemistry C (2021).
6. The Relation of Phase‐Transition Effects and Thermal Stability of Planar Perovskite Solar Cells. Advanced Science (2018).