Perovskite Solar Cell Sintering via Intense Pulsed Light

The patent employs rapid thermal annealing that induces transient phase transitions in the perovskite material, heating it above 150°C for very short durations (seconds to minutes) to promote crystal growth and surface coverage, then rapidly cooling to prevent decomposition. This controlled phase transition approach allows the material to temporarily access high-temperature phases that enhance crystallization without permanently decomposing into lead iodide and methylammonium iodide.

The patent utilizes periodic heating and cooling cycles during the annealing process, applying thermal energy in controlled intervals rather than continuous heating. This periodic thermal action allows the perovskite to undergo repeated cycles of crystal growth followed by stabilization, enabling progressive improvement in surface coverage and crystal size while preventing cumulative thermal degradation that would occur with sustained high-temperature exposure.

The patent applies preliminary low-temperature treatment or controlled solvent annealing before the main high-temperature annealing step. This preliminary action pre-organizes the perovskite precursors and fills pores at lower temperatures where agglomeration is minimized, creating a more uniform initial structure that can then be densified at higher temperatures without transitioning to discrete island morphology.

The patent systematically varies multiple parameters including annealing temperature, time, atmosphere composition, and cooling rate to optimize the balance between surface coverage and morphology. By changing these parameters in combination rather than relying on high temperature alone, the process achieves complete pore filling and continuous layer formation while suppressing the agglomeration that would lead to discrete island structures.

The patent replaces conventional slow thermal diffusion-based annealing with rapid thermal processing using flash heating or microwave annealing techniques. These alternative heating mechanisms transfer energy much faster than conventional conduction-based heating, enabling complete perovskite formation, crystal growth, and pore filling in seconds to minutes rather than hours, thereby achieving both high productivity and high film quality simultaneously.

The patent employs periodic pulsed heating cycles with very short duration (milliseconds to seconds) repeated multiple times. Each pulse provides sufficient energy for localized crystal growth and pore filling, while the brief intervals between pulses allow rapid heat dissipation that prevents bulk material degradation. This periodic action accumulates the beneficial effects of multiple heating events while maintaining overall process speed for scalable manufacturing.