Influence of Nonfused Cores on the Photovoltaic Performance of Linear Triphenylamine-Based Hole-Transporting Materials for Perovskite Solar Cells

Abstract

The core plays a crucial role in achieving high performance of linear hole transport materials (HTMs) toward the perovskite solar cells (PSCs). Most studies focused on the development of fused heterocycles as cores for HTMs. Nevertheless, nonfused heterocycles deserve to be studied since they can be easily synthesized. In this work, we reported a series of low-cost triphenylamine HTMs (M101-M106) with different nonfused cores. Results concluded that the introduced core has a significant influence on conductivity, hole mobility, energy level, and solubility of linear HTMs. M103 and M104 with nonfused oligothiophene cores are superior to other HTMs in terms of conductivity, hole mobility, and surface morphology. PSCs based on M104 exhibited the highest power conversion efficiency of 16.50% under AM 1.5 sun, which is comparable to that of spiro-OMeTAD (16.67%) under the same conditions. Importantly, the employment of M104 is highly economical in terms of the cost of synthesis as compared to that of spiro-OMeTAD. This work demonstrated that nonfused heterocycles, such as oligothiophene, are promising cores for high performance of linear HTMs toward PSCs.

Core Structure Engineering in Hole‐Transport Materials to Achieve Highly Efficient Perovskite Solar Cells

“…However, its tedious synthesis and purification is a major obstacle for large‐scale production. To solve this problem and to further study the relationship between HTM structure and device performance, new organic small molecules with appropriate energy levels and favorable hole‐transporting ability were developed to replace spiro‐OMeTAD . The selection of the core structure is of great concern for designing organic small‐molecule‐based HTMs.…”

“…The effects of different cores on the conductivity, hole mobility, energy levels, and solubility of HTMs were also investigated. For example, Qiao and co‐workers synthesized six triphenylamine HTMs with different non‐fused heterocycles as core units, which have a great influence on the optical, electrochemical, and photovoltaic properties of HTMs . Hua and co‐workers reported two molecules (YN1 and YN2), which incorporated benzothiadiazole (BT) and thienopyrazine (TP) units as core structures for comparison .…”

“…To solvet his problem and to furthers tudy the relationship between HTMs tructure and device performance, new organic small molecules with appropriate energy levels andf avorable hole-transporting ability wered evelopedt or eplace spiro-OMeTAD. [16][17][18][19][20][21][22][23] The selection of the core structure is of great concern for designing organic small-molecule-based HTMs. In recenty ears, as eries of HTMs with phenothiazine, [24] acridine, [25] benzo [1,2- [26] truxene, [27] tetraphenylethylene, [28] and others as the core structures were reported.…”

“…chemical, and photovoltaic properties of HTMs. [21] Hua and coworkers reported two molecules (YN1 and YN2), which incorporated benzothiadiazole (BT) and thienopyrazine (TP) units as core structures for comparison. [29] YN2, with the stronger electron-withdrawing core structure, showedasuperior PCE of 19.27 %.…”

New ferrocenyl-containing organic hole-transporting materials for perovskite solar cells in regular (n-i-p) and inverted (p-i-n) architectures

“…Compared with inorganic HTMs and organic polymer HTMs, organic smallmolecule HTMs have the advantages of facile synthesis, exible modication of structure, and easy purication. [17][18][19][20][21][22] Organic small-molecule HTMs can reach high hole mobility by possessing tunable energy levels, suitable solubility in organic solvents, and good lm-forming properties. [23][24][25][26] Ferrocene is an organometallic compound with a sandwich structure.…”