Incorporation of green solvent for low thermal budget flower-like Copper(I) Iodide (γ-CuI) for high-efficiency solar cell

High conductivity, density, and uniform Copper(I) Iodide (CuI) as Hole Transporting Layer (HTL) was prepared directly on an Indium-doped Tin Oxide (ITO) substrate. A new green solvent, namely Monoethanolamine (MEA) with no additional additives procedures was presented for the preparation, though the fabricated CuI films produced a notable result of HTL for perovskite solar cell (PSC) applications. The growth of γ-CuI can be formed at the lower temperature of 350 °C, thereby lowering the fabrication cost since a high temperature involved fabrication method incurs large costs. The optimized annealing temperature of 80 °C has attained a pristine morphology structure with high conductivity of 28.38 S/cm. Besides, the SCAPS-1D simulation was used to construct an efficient CuI-based PSC using the experimental data collected of fabricated CuI films and attained a PCE of 21.37%, FF of 82.77%, J sc of 22.74 mA/cm 2 and V oc of 1.14 V. Interestingly, this is the first report proposing the use of MEA as a CuI solvent, demonstrating the effective combination of solvent and annealing temperature can yield a desirable CuI structure. With that, HTL films can be prepared in simple, inexpensive, and rapid, thus reducing the cost of solar cell production.