GUWAHATI, June 2: A research team at the Indian Institute of Technology-Guwahati (IIT-G) has developed a new technology on perovskite semiconductor material, known for its potential applications in solar cells and resistive-switching (memristor/R-RAM) devices.
Perovskites are a class of materials with a distinctive crystal structure that enables strong light absorption and efficient charge separation for high-performance solar cells.
Perovskite solar cells comprise multiple functional layers, where photogenerated charge carriers are extracted through selective transport layers to generate electricity.
However, losses at interfaces arising from surface defects, chemical redox reactions and energy-level mismatches lead to charge trapping and recombination. These challenges are further intensified under environmental stress, such as moisture, heat and oxygen, resulting in degradation and reduced operational stability, thereby limiting the practical use of perovskites in real-world scenarios.
However, the resistive switching behaviour of perovskite memristors is often affected by uncontrolled ion migration, defect-assisted conduction and interfacial instabilities, leading to variability in switching parameters.
These issues result in poor switching uniformity, limited endurance, retention degradation and an incomplete understanding of the underlying switching mechanism.
To address these limitations, Prof. Parameswar K. Iyer from the Department of Chemistry and Centre for Nanotechnology, along with his research team, developed a molecular interface engineering method using two specially designed bright donor-acceptor organic molecules.
These strategic organic compounds are deposited as 10 to 15 nm ultrathin layers (a hundred thousand times thinner than a human hair) between the charge-transport layer and the perovskite layer as part of the device engineering tactic.
These organic molecules control how electrical charges behave at the interface and reduce defects, resulting in the easy and smooth flow of charges created by sunlight across the interface.
This approach enabled solar cells to achieve an efficiency of 25.73 percent, corresponding to the conversion of nearly one-quarter of incident sunlight into electricity, which is highly competitive among state-of-the-art devices of this class.
The research team also found that the interfacial engineering approach retained approximately 90 percent of its initial performance after prolonged storage under ambient conditions and about 75 percent under continuous thermal and light stress, highlighting the robustness of the developed materials.
Beyond solar cells, the team demonstrated that the same (FA-based) perovskite material can be integrated into memristor devices using a thin 220-nm-active layer, showcasing its multifunctional potential. These devices exhibit stable low-power switching, multistate memory performance, and reliable endurance, making them promising candidates for next-generation memory and crossbar arrays for neuromorphic computing.
The study also provides important insights into the switching mechanism governed by defect states and ion migration.
Speaking about the real-world usage of the developed materials, Prof. Iyer said, “This work demonstrates the potential of perovskite-based semiconductor technologies for next-generation solar cells and memory devices. The synthesised novel organic molecules enable improved interfacial engineering for highly efficient and stable solar energy conversion, while the same material platform exhibits reliable resistive switching for advanced memory and neuromorphic computing applications.
“Such advances could accelerate the large-scale commercialisation of integrated optoelectronic systems combining energy harvesting, information storage, and intelligent computing within a single technological framework,” he said.
In addition to the development of low-cost and efficient solar cells and memory devices, these improved perovskite systems can also support energy-efficient computing approaches.
