RESUMO
Defects and energy offsets at the bulk and heterojunction interfaces of perovskite are detrimental to the efficiency and stability of perovskite solar cells (PSCs). Herein, we designed an amphiphilic π-conjugated ionic compound (QAPyBF4 ), implementing simultaneous defects passivation and interface energy level alignments. The p-type conjugated cations passivated the surface trap states and optimized energy alignment at the perovskite/hole transport layer. The highly electronegative [BF4 ]- enriched at the SnO2 interface featured desired band alignment due to the dipole moment of this interlayer. The planar n-i-p PSC had an efficiency of 23.1 % with Voc of 1.2â V. Notably, the synergy effect elevated the intrinsic endothermic decomposition temperature of the perovskite. The modified devices showed excellent long-term thermal (85 °C) and operational stability at the maximum power point for 1000â h at 45 °C under continuous one-sun illumination with no appreciable efficiency loss.