Impact of Peripheral Groups on Phenothiazine-Based Hole-Transporting Materials for Perovskite Solar Cells

Abstract

Three hole-transporting materials (HTMs) based on the phenothiazine core containing 4,4-dimethyltriphenylamine (Z28), N-ethylcarbazole (Z29), and 4,4-dimethoxytriphenylamine (Z30) as the peripheral groups connected by double bonds were designed and synthesized. The HTMs were tested in mixed cation/anion perovskite solar cells (PSCs) of the composition [(FAPbI 3 ) 0.85 (MAPbBr 3 ) 0.15 ]. A power conversion efficiency (PCE) of 19.17% under 100 Mw cm −2 standard AM 1.5G solar illumination was obtained using Z30. Importantly, the devices based on Z30 show better stability compared to those using Z28 and Z29 when aged under ambient air of 40% relative humidity in the dark for 1008 h and under continuous sunlight soaking without encapsulation for 600 h. These results indicate that the 4,4-dimethoxytriphenylamine is a promising peripheral group in combination with the phenothiazine core, providing an alternative to develop small molecular HTMs for efficient and stable PSCs.

A structure–property study of fluoranthene-cored hole-transporting materials enables 19.3% efficiency in dopant-free perovskite solar cells

“…These results reveal a substantial overlap between the LUMO and HOMO that will be benecial to the generation of excitons and hole transport. 55,56 In addition, the trend of the calculated HOMO levels is also in good accordance with those from CV measurements. By introducing ethylene linkage or forming branched structures, the calculated HOMOs of the corresponding HTMs can be increased accordingly, while metamethoxy substituents are found to effectively reduce the calculated HOMO of FBA3 with a value of À4.86 eV.…”

Introduction of Hydrophobic Ammonium Salts with Halogen Functional Groups for High‐Efficiency and Stable 2D/3D Perovskite Solar Cells

“…However, poor device stability under operation falls far short of the market requirement, which is one of the crucial factors hindering the future commercialization of PSCs . Tremendous efforts from researchers have been made to improve the stability of PSCs under different test environments . The emergence of 2D and mixed‐dimensional (MD) perovskites has brought the dawn to the commercialization of PSCs .…”

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

“…[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. The effects of different cores on the conductivity,h ole mobility,e nergy levels,a nd solubility of HTMs were also investigated.…”