Comparison of interfacial bridging carbon materials for effective carbon-based perovskite solar cells

As a hole transport materials (HTMs) and noble-metal free perovskite solar cells (PSCs), carbon-based PSCs (C-PSCs) have drawn much attention due to its low cost and excellent stability. The interfacial engineering, between perovskite and counter electrodes (CEs), played a crucial role in charge collection and affected the performance of C-PSCs. Herein, the systematic investigation of interfacial bridging carbon materials has been carried out to improve the interfacial contact. Results demonstrated that the morphology of interfacial bridging carbon materials played more important role than their energy band and conductivity, where carbon nanotube (CN) showed much better interfacial bridging effect and energy level alignment than other carbon materials. We achieved both the high power conversion efficiency (PCE) (15.09%) and stability in C-PSCs without HTMs due to the optimal interfacial bridging carbon material. It could retain 67% of their initial PCE after storing for 340 h under the rigorous environmental condition without any encapsulation (air atmosphere, 85 °C, 65% RH).