Liquid metal templates increase the efficiency of printable perovskite solar cells
A research team from Yunnan University has made a major advance in the field of printable mesoscopic perovskite solar cells (p-MPSCs) by introducing liquid gallium nanodroplets as heteroepitaxial templates to control crystal growth. The breakthrough, led by Professor Qingju Liu, enables significantly higher efficiency and stability than previously achievable with this low-cost solar technology.
Printable mesoscopic perovskite solar cells offer great potential as a scalable and stable alternative to conventional solar photovoltaics. However, their energy conversion efficiency has long lagged behind planar perovskite cells due to limited crystal growth within the mesoporous oxide scaffold. These restrictions produce small grains that suffer from increased charge recombination.
To address this, Liu’s team embedded liquid gallium nanodroplets into the mesoporous TiO2 layer. When exposed to air, the droplets form an ultrathin Ga2O3 shell that serves as a precise epitaxial template. Atomic resolution imaging and density functional theory calculations confirmed that the plane of the MAPbI3 perovskite (110) is perfectly aligned with the Ga2O3 surface (400), exhibiting a lattice mismatch of only 0.32%. This near-perfect alignment guides the formation of large, oriented perovskite crystals measuring over 200 nanometers within the confined structure.
The resulting device achieved a record power conversion efficiency of 20.2% on an area of 0.10 cm2 with negligible hysteresis. It also showed remarkable durability, maintaining 97% of its original performance after 3000 hours of continuous use at high humidity (85% RH) and elevated temperature (55 C).
The study highlights the potential of liquid metal ‘seeding’ to achieve crystal growth in confined systems and to advance the scalable production of high-performance, stable perovskite solar panels. The work was supported by multiple national and provincial programs in China, including the National Key R and D Program, the National Natural Science Foundation of China and the Yunnan Precious Metals Laboratory.
Research report:Liquid Ga-heteroepitaxy with nanodroplets of MAPbI3 for highly efficient printable mesoscopic perovskite solar cells
