Performance Improvement in Low-Temperature-Processed Perovskite Solar Cells by Molecular Engineering of Porphyrin-Based Hole Transport Materials

Abstract

Porphyrin derivatives have recently emerged as hole transport layers (HTLs) because of their electron-rich characteristics. Although several successes with porphyrin-based HTLs have been recently reported, achieving excellent solar cell performance, the chances to improve this further by molecular engineering are still open. In this work, Zn porphyrin (PZn)-based HTLs were developed by conjugating fluorinated triphenylamine (FTPA) wings at the perimeter of the PZn core for low-temperature perovskite solar cells (L-PSCs). The fluorinated PZn-HTLs (PZn–2FTPA and PZn–3FTPA) exhibited superior HTL properties compared to the nonfluorinated one (PZn–TPA). Moreover, their deeper highest occupied molecular orbital energy levels were beneficial for boosting open-circuit voltages, and their enhanced face-on stacking improved the hole transport properties. The L-PSC using PZn–2FTPA achieved the highest performance of 18.85%. Thus far, this result is one of the highest reported power conversion efficiencies among the PSCs using porphyrin-based HTLs.

Efficiencyvs.stability: dopant-free hole transporting materials towards stabilized perovskite solar cells

“…Azmi et al reported Zn porphyrin-based HTMs with conjugating fluorinated triphenylamine wings. The best among the series P Zn -2FTPA exhibited a PCE of 18.85% 139. Chiang et al designed and synthesized the dimeric porphyrin material WT3 with a suitable HOMO level and hole mobility leading to an excellent PCE of 19.44% 140.…”

Effects of methoxy group(s) on D-π-A porphyrin based DSSCs: efficiency enhanced by co-sensitization

“…Porphyrins are widely present in biological systems and have shown impressive performance for many optoelectronic applications, such as organic light-emitting diodes, hole-transporting materials for perovskite solar cells, sensitizers for photodynamic therapy, and DSSCs. 8–14…”

Recent progress in porphyrin- and phthalocyanine-containing perovskite solar cells

“…Azmi et al synthesized three types of zinc porphyrins bearing triphenylamino groups (7)(8)(9) to investigate the effect of introducing uorine, an electrophilic group, on the porphyrin substituents with the aim of improving electrochemical properties and device performance. 48 The HOMO levels by CV measurement were À5.14 eV for 7, À5.37 eV for 8, and À5.24 eV for 9. Introducing more uorine atoms or positioning a uorine atom close to the porphyrin core lowered the HOMO level.…”