Design and Synthesis of Hole Transporting Materials for Perovskite Solar Cells

Perovskite solar cells (PSCs) are one of the emerging technologies in the field of photovoltaics. Hole transporting materials (HTMs) play essential roles in improving the device performances; their main task is to capture the hole formed after light absorption in the perovskite layer and transport it to the cathode. The goal of this study was to synthesize new, cheaper and more stable organic HTMs than Spiro-OMeTAD, an organic molecule showing the best performances in PSC devices to date. Organometallic reactions were used to form new carbon-carbon and carbon-nitrogen bonds to assemble different molecular fragments in simple way; in particular, we used palladium catalyzed Suzuki-Miyaura and Buchwald-Hartwig cross-couplings to prepare two new HTMs (HTM1 and HTM2, see figure 1). These compounds were then used to study how small structural modifications may affect the performance of the resulting PSCs.