Non-halogenated solvent processed new Spiro-type hole transport material for efficient perovskite solar cells

Perovskite solar cells (PSCs) are the fastest developing solar cells and pull in a part of attention due to the prevalent advantages such as solution process, light weight, flexibility, and low cost. In common, Spiro-OMeTAD is the most used hole transport material (HTM) in PSCs. Thanks to its good merits, such as forming smooth surface films, matching energy levels with perovskites, and high tolerance with dopants. Therefore, Spiro-P was designed and synthesized by using an end group strategy (Propargyloxy). Additionally, the thermal, optical, and electrochemical properties of the new HTM and device performance were investigated. As a result, the Spiro-P HTM based device showed high power conversion efficiency (PCE) of 22.36% with an open circuit voltage (Voc) of 1.102 V, a short-circuit density (Jsc) of 26.20 mA/cm2 and a fill factor (FF) of 77.43%. This investigation shows that the new synthesized Spiro-P is a potential HTM to achieve good performance in the field of PSCs.