Compared with traditional n-i-p perovskite solar cells, inverted (p-i-n) perovskite solar cells have higher stability and lifetime, but generally have lower power conversion efficiency (PCE). Defects and non-ideal charge transport at the interface between the perovskite active layer and the charge transport layer are one of the key factors affecting the efficiency and stability of inverted perovskite solar cells. Therefore, selecting effective interfacial layer materials and further enhancing the performance and stability of inverted perovskite solar cells (PSCs) are crucial for their commercial development.

　　A study published in the journal Science (IF 47.728) in April 2022. The research team used ferrocenyl-bis-thiophene-2-carboxylate (FcTc₂) to provide a new idea for designing stable and efficient interface materials for perovskite solar cells. The ferrocene organometallic derivatives possess the excellent properties of both organic and inorganic materials. As a functionalized interface layer, they can effectively reduce the non-radiative recombination in the interface of inverted perovskite solar cells and accelerate the charge transfer at the same time.

　　The researchers conducted experiments by using Enlitech’s ELCT-3010 system (now REPS perovskite photovoltaic V_OC loss analysis system) and other instruments. The results showed that the open-circuit voltage (V_OC) and fill factor (FF) of the device functionalized through the FcTc₂ interface were improved. A record efficiency of 25% for inverted perovskite solar cells was reached (certified efficiency of 24.3%). In addition, it still maintained 98% of the initial efficiency after 1500 hours of long-term simulated AM1.5 illumination; the stability test in hot and humid environment (85°C/85% RH) passed the international standard of IEC 61215:2016.

　　Enlitech’s REPS Perovskite Photovoltaic Voc-loss Analysis System can measure Electroluminescence (EL) quantum efficiency (EQE_EL) and very low EL-EQE signals be detected (as low as 10^-5%, or 7 orders of magnitude). Furthermore, the analyzing software, SQ-VLA, can help users match the calculated Voc-loss with the real Voc-loss of the IV curve, thereby promoting the research progress and journal publication.