Laser-reduced graphene oxide as electrode for ITO-free perovskite solar cells and supercapacitors

Laser-reduced graphene oxide (LrGO) is a promising material for fabricating indium tin oxide (ITO)-free perovskite solar cells (PSCs) and supercapacitors (SCs). In this work, GO films were deposited by spray coating and then reduced and patterned by laser processing to form conductive LrGO electrodes for PSCs and micro-SCs. The optimized LrGO films exhibited transmittance of 38% and sheet resistance of approximately 400 Ω∙sq. −1 . ITO-free PSCs employing LrGO as the transparent conductive electrode achieved a power conversion efficiency (PCE) of 4.78% under 1 sun illumination. Furthermore, under indoor light conditions of 1000 lx, the LrGO-based PSCs achieved a PCE of 10.49%. Optical simulations revealed that the main limitation of LrGO-based PSCs was the parasitic absorption of the thick LrGO layer. Additionally, LrGO-based micro-SCs were fabricated by direct laser scribing. The micro-SCs achieved areal capacitance of 4.3 mF∙cm −2 at a scan rate of 5 mV∙s −1 , comparable to previously reported rGO-based micro-SCs. The stable cyclic voltammetry and galvanostatic charge-discharge profiles at various scan rates and current densities indicated good electrochemical stability and effective ion transport. This work demonstrates the potential of LrGO as a low-cost, solution-processable material for fabricating ITO-free PSCs and SCs on the same substrate, enabling self-powering devices for indoor applications.