Researchers at Hellenic Mediterranean University (HMU), the HMU Research Center’s Institute of Emerging Technologies (i-EMERGE), the Foundation for Research and Technology’s Institute of Electronic Structure and Laser (FORTH-IESL), and the University of Crete have used laser-reduced graphene oxide (LrGO) as a transparent conductive electrode for both perovskite solar cells and micro-supercapacitors fabricated on the same glass substrate.
The team deposited graphene oxide (GO) films by spray coating, then reduced and patterned them using an ultrashort-pulse infrared laser to form conductive LrGO electrodes, avoiding the more complex and costly chemical vapor deposition (CVD) and transfer processes typically used to put graphene into solar cells. The optimized LrGO films reached a sheet resistance of about 400 Ω per square at 38% optical transmittance.
Used as the transparent electrode in indium tin oxide (ITO)-free perovskite solar cells, the LrGO-based devices reached a 4.78% power conversion efficiency (PCE) under standard 1-sun illumination, and notably 10.49% PCE under indoor warm light conditions (1000 lux), which the researchers attribute to LrGO’s light-absorption profile favoring longer wavelengths. Optical simulations showed the main performance limit was parasitic light absorption within the LrGO layer itself, pointing to a fairly direct path for improvement.
The same laser-reduction process was also used to directly write interdigitated micro-supercapacitors onto the GO film, reaching an areal capacitance of 4.3 mF/cm² with stable charge-discharge behavior. The researchers say this points toward fully ITO-free, self-powered indoor devices that combine light harvesting and energy storage on a single glass substrate.

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