Unadorned Molecular Engineering of Phenoxazine-Core-Based Hole-Transport Materials for Sustainable Perovskite Solar Cells

Abstract

The pressing challenges that bottleneck perovskite solar cell (PSC) commercialization depend on low-cost, stable, and effective hole-transport materials (HTMs). Given the numerous proposed small molecules, the D−A−D−A−D system surfaces as a suitable HTM for its striking energy landscape and efficient charge transport. An economically straightforward synthesis of a phenoxazine-core-based HTM is the need of the hour. Herein a facile sparing route is demonstrated to synthesize nonconventional HTMs and compare their performances to the conventional 2,2′,7,7′-tetrakis(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene (Spiro-OMeTAD). Intriguingly, periodic stability studies with champion devices of phenoxazine-core-based (2Z,2′Z)-3,3′-[10-(2-ethylhexyl)-1H-phenoxazine-3,7-diyl]bis [2-(3,5dimethoxyphenyl)acrylonitrile] (HTM3) retained a conversion efficiency of ∼90% compared to the Spiro-OMeTAD retention at ∼70% over 25 days of its initial values. Moreover, light intensity dependence research showed that HTM3 has a better hole-transporting ability and can resist charge recombination efficiently. These results indicate that phenoxazine-based compounds are promising HTM candidates for fabricating stable PSCs.

Unveiling Charge Carrier Dynamics in CsPbBr3 Perovskites with Hole Transport Layers: Insights from Pattern-Illumination Time-Resolved Phase Microscopy

“…However, its high synthesis cost and cumbersome purification process limit its application for large-scale fabrication of PSCs. In addition, the low hole mobility of spiro-OMeTAD (10 –4 cm 2 V –1 s –1 ) requires the addition of dopants. , However, the doping does not affect the interfacial charge transfer from the doping dependence of the carrier behavior in our measurement. PTAA is an excellent hole transporting and electron blocking semiconductor material due to its excellent hole mobility in the range of 10 –2 to 10 –3 cm 2 V –1 s –1 and electron-rich components; PTAA also exhibits mechanical robustness and moisture resistance and is less degraded than spiro-OMeTAD.…”

Donor engineering of a benzothiadiazole-based D–A–D-type molecular semiconductor for perovskite solar cells: a theoretical study

“…As discussed above, the main focus of recent works is to develop new acceptors; however, the influences of electron-donating moieties on the optoelectronic and charge transfer properties of D–A–D HTMs have not been fully researched. In this work, based on the typical D–A–D molecule YN1, 31 six new molecules are designed by replacing the triphenylamine donor with the ethyl-substituted phenoxazine (POZ), 44–46 phenothiazine (PTZ) 47–50 and carbazole (CZ) 51,52 groups, respectively. Meanwhile, the thiophene and furan units are also added as the spacer moiety to extend the π-conjugation length, as displayed in Fig.…”