Indian scientists have fabricated perovskite mini-modules with reduced graphene oxide interface engineering, achieving 16.6% efficiency and more than 1,300 hours of stable operation. The graphene oxide layer improves film quality, reduces defects, improves charge transport and enables scalable manufacturing, offering a promising route to efficient and sustainable perovskite solar panels.
Researchers at Prabhat Kumar College in India have fabricated mini Perovksite solar modules with more than 1,300 hours of operational stability.
“We demonstrated a scalable interface engineering approach using reduced graphene oxide (r-GO) to significantly improve the performance of perovskite solar mini-modules,” said the study’s lead author Asim Guchhait, pv magazine. “The r-GO interface improves the quality of the perovskite film, reduces defect-induced recombination and improves charge transport.”
The scientists developed an interface passivation strategy intended to apply r-GO to self-assembled monolayer (SAM)-based hole transport layers (HTLs) to improve surface properties and control perovskite crystallization. They explained that although SAMs are valued for their stability, transparency and good alignment at the energy level, they suffer from mobility at low gaps and surface defects. The introduction of r-GO alleviates these limitations and improves hole extraction efficiency, while also improving perovskite film coverage and device stability by acting as a barrier layer.
The spin coating research group reduced r-GO to the SAM to modify the interface before depositing the perovskite layer using a two-step spin coating method with anti-solvent treatment. It then built the solar cell type used for the modules by using a substrate made of glass and indium tin oxide (ITO), a sputtered nickel oxide (NiOx) as the seed layer of SAM, the SAM, a perovskite absorber, an electron transport layer (ETL) based on a buckminsterfullerene (C60), a transparent back contact made of aluminum doped zinc oxide (AZO), a bathocuproin (BCP) buffer layer and a copper (Cu) metal contact.
The 22.59% efficient cell was assembled via a monolithic junction via a P1-P2-P3 laser writing process. Initially, P1 writing creates insulation lines in the ITO layer, followed by cleaning and deposition of NiOx, SAM, and r-GO layers. The perovskite absorber is then deposited using a two-step spin-coating method with anti-solvent treatment and thermal annealing. P2 writing removes selected layers to allow electrical connection between adjacent subcells after deposition of copper electrodes. P3 writing then isolates the top electrodes, preventing electrical crosstalk and completing the module.
The photovoltaic performance of the 5 cm × 5 cm mini-modules fabricated with the proposed cell structure was evaluated using JV measurements under standard lighting conditions with a calibrated solar simulator and source meter. Non-encapsulated perovskite modules with an active surface area of 9.2 cm2 were found to achieve an energy conversion efficiency of 16.6%, compared to 15.13% for control devices built without the r-GO layers.
The scientists explained that the r-GO modified substrates showed improved perovskite film quality with fewer defects and better growth kinetics, which in turn reduced grain boundaries and trap density, leading to better charge transport. Electrical analyzes confirmed reduced defect density, enhanced recombination resistance, and enhanced carrier dynamics. Furthermore, the r-GO treated devices showed excellent stability, maintaining efficiency above 95% after 1,300 hours of operation and storage, far outperforming the control devices.
“These results demonstrate that r-GO interfacial passivation in combination with optimized transport layers is an effective route to more efficient and durable perovskite modules,” the academics said.
The study introduced the new cell and module concept “Interface engineering for the stabilization of efficient perovskite mini-modules with an operational stability of more than 1300 hours”, published in Solar energy materials and solar cells. “This work provides a promising path for bridging the gap between laboratory-scale devices and commercially viable perovskite solar panels,” said Guchhait.
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