A fluorescent sensor to detect lead leakage from perovskite solar cells

Hybrid perovskites have been considered a hot material in the semiconductor industry; included as an active layer in advanced devices, from light emitting applications to solar cells, where they lead as a new strategic solution, they promise to be the next generation high impact class of materials. However, the presence - in most cases - of lead in their matrix, or lead byproducts as a consequence of material degradation, such as PbI₂, is currently hindering their massive deployment. Here, we develop a fluorescent organic sensor (FS) based on the Pb-selective BODIPY fluorophore that emits when the analyte - lead in this case - is detected. We carried out a fluorimetric analysis to quantify the trace concentration of Pb²⁺ released from lead-based perovskite solar cells, exploring different material compositions. In particular, we immersed the devices in rainwater, to simulate the behavior of the devices under atmospheric conditions when the sealing is damaged. The sensor is studied in a phosphate buffer solution (PBS) at pH 4.5 to simulate the pH of acidic rain, and the results obtained are compared with ICP-OES measurements. We found that with fluorometric analysis, lead concentration could be calculated with a detection limit as low as 5 μg l^-1, in agreement with ICP-OES analysis. In addition, we investigated the possibility of using the sensor on a solid substrate for direct visualization to determine the presence of Pb. This can constitute the base for the development of a Pb-based label that can switch on if lead is detected, alerting any possible leakage.

The levelized cost of electricity from perovskite photovoltaics

The levelized cost of electricity (LCOE) is a techno-economic analysis that evaluates the cost potential of any electricity-producing technology. LCOE represents a powerful metric to compare the most efficient renewable resources in the framework of the energy transition. Perovskite solar cells (PSCs) are an emerging technology with great potential to establish a leading position in the photovoltaic (PV) market, particularly in those regions that cannot rely on crystalline silicon manufacturing. However, like many emerging technologies, their positioning in the PV market is still quite speculative. Here, we revise the different models to evaluate the LCOE of PSCs, paying attention to the impact of performance, stability, and manufacturing costs. We consider the difference in performances from lab-record devices to modules fabricated in industrial production lines. We identify the key role of the degradation that is hindering the commercialization of PSCs and we analyze the manufacturing cost and the supply chain availability. From our analysis, we restricted the LCOE to 3-6 cents (USD) per kWh, which is competitive with the best of the mainstream silicon technologies (passivated emitter and rear contact, PERC). In conclusion, we highlight the future challenges to refine the LCOE calculations, including temperature effects.