Nickel oxide (NiO ) is commonly used as a holetransporting material (HTM) in p-i-n perovskite solar cells. However, the weak chemical interaction between the NiO and CH NH PbI (MAPbI ) interface results in poor crystallinity, ineffective hole extraction, and enhanced carrier recombination, which are the leading causes for the limited stability and power conversion efficiency (PCE). Herein, two HTMs, TRUX-D1 (N ,N ,N -tris(9,9-dimethyl-9H-fluoren-2-yl)-5,5,10,10,15,15-hexaheptyl-N ,N ,N -tris(4-methoxyphenyl)-10,15-dihydro-5H-diindeno1,2-a:1',2'-cfluorene-2,7,12-triamine) and TRUX-D2 (5,5,10,10,15,15-hexaheptyl-N ,N ,N -tris(4-methoxyphenyl)-N ,N ,N -tris(10-methyl-10H-phenothiazin-3-yl)-10,15-dihydro-5H-diindeno1,2-a:1',2'-cfluorene-2,7,12-triamine), are designed with a rigid planar C symmetry truxene core integrated with electron-donating amino groups at peripheral positions. The TRUX-D molecules are employed as effective interfacial layer (IFL) materials between the NiO and MAPbI interface. The incorporation of truxene-based IFLs improves the quality of perovskite crystallinity, minimizes nonradiative recombination, and accelerates charge extraction which has been confirmed by various characterization techniques. As a result, the TRUX-D1 exhibits a maximum PCE of up to 20.8% with an impressive long-term stability. The unencapsulated device retains 98% of their initial performance following 210 days of aging in a glove box and 75.5% for the device after 80 days under ambient air condition with humidity over 40% at 25 °C.