Long-Term Outdoor Testing of Perovskite Mini-Modules: Effects of FACl Additives

Abstract

The outdoor performance monitoring of perovskite modules over 16 weeks is reported. Two different types of active perovskite layers were studied: one type contained formamidinium chloride (FACl) halide additives and the other contained no additives with the main purpose to investigate performance trends during the outdoor exposure of those type of devices. Long-term side-by-side outdoor testing of devices with and without halide additives was not implemented in the past and merits investigation in order to determine the impact of additives on perovskite performance and stability. Although the two types of modules displayed similar initial outdoor performance characteristics, their outdoor performance evolution differed. Different degradation rates between the modules with and without additives were obtained just after field installation. In particular, the modules with additives exhibited higher performance degradation under open-circuit loading conditions between current-voltage (IV) scans. Long-term monitoring of both modules recorded a reduction of the efficiency over the course of the day with subsequent recovery overnight and in many cases during the day. The relative values of performance degradation and overnight recovery were calculated over the timespan of outdoor testing and indicated dominant normalized diurnal performance degradation in one type of modules (without FACl additives) in the range between 15–20% and in the other type of modules (with additives) 5–10%. The dominant normalized performance recovery values found were 25–30% and 5–10%, respectively. Finally, dark lock-in thermography (DLIT) and Raman studies were performed on the exposed devices and revealed differences in hotspot evolution and vibrational modes between the different types of module.

Performance and stability of hybrid organic-inorganic perovskite photovoltaics in outdoor illuminations conditions

“…However, such testing conditions may not accurately simulate real PV module operations [7]. There are very limited reports on outdoor testing of perovskite solar cells under outdoor conditions [7,[19][20][21][22][23]. Our review reports on outdoor measurements of perovskite solar cells shows that there are no reports from Africa climate conditions, characterized by elevated temperatures and strong solar radiation throughout a year.…”

“…To ensure the effectiveness of perovskite PV technology at an affordable cost, it is crucial to guarantee that PV modules possess long-term stability and high power conversion efficiency (PCE) comparable to conventional PV systems. Yet, PSCs have not attained the desired stability necessary for commercializing this technology [18,19]. Perovskite devices or films degrade rapidly under environmental exposures such as high temperatures, illumination, moisture, and oxygen.…”