Highly efficient perovskite solar cells based on symmetric hole transport material constructed with indaceno[1,2-b:5,6-b']dithiophene core building block

Two novel hole transport materials (HTMs) with indaceno[1,2-b:5,6-b']dithiophene (IDT) as core building blocks, termed IDT1 and IDT2, were designed and synthesized. The side alkyl chains were introduced to regulate and control the morphology and stacking behavior of HTMs, and the peripheral triarylamine arms were introduced to adjust the energy levels and to facilitate efficient hole transport. Applied in mesoporous structured perovskite solar cells (PSCs), HTM IDT1 achieved higher power conversion efficiency (PCE, 19.55%) and better stability than Spiro-OMeTAD (19.25%) and IDT2 (15.77%) based PSC. These results suggest the potential of IDT1 as a promising HTM for PSCs.