The optoelectronic properties of acetylene based compounds as hole transporter in perovskite solar cells: A computational study

Abstract

Hole transport materials (HTMs) are pivotal components in perovskite solar cells (PSCs), significantly influencing their power conversion efficiency (PCE). This study explores the potential of various diacetylide-triphenylamine (DATPA) derivatives (HTMs 1–8) to function as hole transporters, employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations.

The energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), as well as the band gap, were computed using the B3LYP/6-311G(d) level of theory. The findings reveal that, with the exception of HTM 8, these compounds exhibit suitable HOMO and LUMO levels relative to the perovskite layer and possess a lower band gap energy compared to the commonly used spiro-OMeTAD.

Additionally, the calculation of hole mobility (Kh) using the Marcus method demonstrated a satisfactory value, substantiating the applicability of these compounds as HTMs. Further calculations of parameters such as hole reorganization energy (λh), absolute hardness (η), ionization potential (IP), electronic affinity (EA), solubility (ΔGsolv), and exciton binding energy (Eb) affirm that these compounds are promising candidates for hole transport in perovskite solar cells. Notably, the compound HTM 2 (NMe2-DATPA) outperforms the others in hole transfer efficiency.