New approach to solar cell manufacture could make perovskite panels more efficient and longer lasting

The study, which has been published in Nature Energy, details a method that works by placing two types of perovskite film in contact with each other. That contact alone triggers a molecular interaction at the interface, which reorganises the crystal structure of the light-absorbing layer throughout its entire depth. The result is a more ordered, more durable material that converts sunlight into electricity more efficiently.  

Solar cells built using the technique achieved a certified power conversion efficiency of 25.61 per cent, independently verified by the Solar Energy Research Institute of Singapore. 

Perovskite solar cells have attracted significant research interest because they are cheaper and easier to manufacture than conventional silicon-based panels. Their commercial potential has been limited, however, by questions over how well they hold up under the heat and humidity conditions of real-world deployment.  

Under accelerated ageing tests, the treated material required roughly twice the thermal energy to degrade compared with comparable materials reported in recent literature – a meaningful improvement in a field where long-term stability is the central challenge. 

The technique works through what the researchers call contact-triggered cationic interaction (CCI). When two perovskite films are placed in physical contact, molecular forces at the interface cause the charged particles – cations – within the light-absorbing layer to adopt a more uniform, aligned arrangement. This reduces the structural defects that cause energy to be lost as heat rather than converted to electricity. The time that charge carriers survive before recombining, a key measure of solar cell quality, increased from 4.48 to 5.89 microseconds in treated material compared with untreated controls.  

To confirm this, the Surrey team used photo-induced force microscopy (PiFM) – a technique that maps chemical signatures at the nanoscale by combining the high resolution of atomic force microscopy with infrared spectroscopy, bypassing the diffraction limit of light. This allowed the researchers to visually validate the precise, uniform formation of chemical bonds triggered by the CCI process, confirming that the molecular alignment occurred exactly as predicted at the film interface.