Enhancement of the photovoltaic performance of HTL-free-perovskite solar cells based on carbon electrode via the modification of electron transport layer with Copper oxide@Polyaniline nanocomposite

Inserting suitable materials into the electron transport layer (ETL) of perovskite solar cells (PSCs) could increase their performance. In the present work, for the first time, we synthesized the copper oxide nanoparticles (CuO-NPs) with a wide-bandgap (5.0 eV) using a relatively high annealing temperature (600 °C) as a metal oxide semiconductor (n-type), and adjusted the value of CuO-NPs bandgap, and work function by adding different amount of polyaniline (PANI), and forming [email protected] nanocomposite (n-composite). Then we have endeavored the insertion of copper [email protected] ([email protected]) n-composite layer (as insertion layer) at mp-TiO2/perovskite interface as the electron transport material (ETM), and modified the pure mp-TiO2 with this nanocomposite as a new bilayer ETL to improve the perovskite crystalline structure, enhance the performance of perovskite solar cells, and solving the instability issue of these cells. The experimental results showed that the mp-TiO2/nanocomposite (1:1) bilayer, has higher conductivity, and better energy levels matching the perovskite layer than the traditional mp-TiO2 film, facilitating charge extraction, and carrier transport from the perovskite layer at the mp-TiO2/n-composite/CH3NH3PbI3 interface. As observed, the change of ETL was shown to boost the produced devices' short-circuit current density (Jsc), and fill factor (FF) properties. [email protected] n-composite (1:1) was used on top of the mp-TiO2 ETL to reach a power conversion efficiency of 13.80%, which is 26.14% greater than pure mp-TiO2 devices. Furthermore, the optimal PSCs that use the mp-TiO2/[email protected] n-composite (1:1) as ETL have exceptional stability, holding over 78% of their initial PCE without encapsulation after 216 h of storage in ambient settings, which is significantly superior to PSCs based on mp-TiO2 only. In addition, by replacing costly metals such as Au with simple carbon paste, the cost of these cells is greatly reduced.