| Work Detail |
An international group of scientists has manufactured an inverted perovskite solar cell that boasts both high power conversion efficiency and a promising high degree of stability. A champion cell achieved a power conversion efficiency of 25.3%, and an encapsulated version retained 95% of initial efficiency after extensive heat and humidity testing. An international team of researchers has demonstrated an inverted perovskite solar cell with a power conversion efficiency of 25.3% and a quasi-steady-state efficiency of 24.8%. Inverted perovskite cells have a device structure known as a “pin,” in which the p-hole selective contact is at the bottom of the intrinsic perovskite i layer and the n electron transport layer is at the top. Conventional halide perovskite cells have the same structure but inverted: a “nip” arrangement. In the nip architecture, the solar cell is illuminated through the electron transport layer (ETL) face; in the pin structure, it illuminates through the surface of the hole transport layer (HTL). The novelty of the research consists of a “coadsorbent strategy that disassembles high-order conglomerates”, which, according to the scientists, had the effect of homogenizing the distribution of phosphonic acid molecules to minimize interfacial recombination. “We studied the agglomeration tendency of the current best SAM based on phosphonic acid through a computational study, and we came closer to mitigating these agglomeration phenomena. In part, we also use a light management strategy to improve the photocurrent,” Somin Park, lead author of the article, told pv magazine . In the article “ Low-loss contacts on textured substrates for inverted perovskite solar cells ,” published in Nature , the group states that they have managed to effectively apply the so-called self-assembled monolayers ( SAM) ultrathin, composed of organic phosphonic acid molecules, to interface surfaces textured in an inverted perovskite cell architecture, optimizing texturing for light management. Park added that the light management of the textured substrates, combined with the uniform coating, gave the expected results, which “excited” the team. The encapsulated version of the device achieved an efficiency of 24.6% and retained 95% of its maximum performance in accelerated aging tests at 65 C and 50% relative humidity for more than 1,000 hours of maximum power point tracking under illumination of 1 sun. The technique could be applied to other types of solar cells. “We envision that our insights into the mechanisms of adsorption of molecules on textured substrates can be easily applied to other perovskite solar cell architectures, such as multijunction devices, advancing both efficiency and stability,” says Park. The research, a collaboration between the laboratories of Edward Sargents group at Northwestern University and Michael Grätzel at , has reportedly produced “one of the most stable perovskite solar cells” and with a high efficiency level. The researchers come from Northwestern University, the University of Kentucky and North Carolina State University (United States), as well as the Ecole Polytechnique Federal de Lausanne (EPFL) (Switzerland), the University of Toronto (Canada) and the Peking University (China). |
