The Solar cells tandem perovskite/organic they represent one of the most promising solutions in the panorama of solar energy, thanks to the possibility of obtaining high efficiency at lower costs Compared to silicon cells. However, the use of broad band perovskiti wide – fundamental to absorb high energy light – entails STABILITY CRITICALITY SERIES. Among these, the poor quality of the lower contact between layers is one of the main obstacles, causing structural defects and degradation of the device.
A team of researchers from the Hong Kong Polytechnic University has identified an effective solution: the use of Quantic points enriched with magnesiumused to improve the interface between the substrate and the film active in the solar cell.
THE Quantic Pointsor quantum dotthey are semi -hoducer nanoparticles that present unique electronic and optical properties. In this study, published on Nature Energythe researchers developed nanoparticles of tin oxide modified through the controlled addition of magnesium in an acid environment. These Quantic points enriched with magnesium They were used as a lower layer to improve the quality of the perovskite CSPBI₂br.
The change brought numerous benefits: more uniform crystallization, Reduction of defects, Best energy alignment And greater chemical stability. In particular, the acidic nature of the nanoparticles has opposed the negative effects of the alkaline versions of the tin oxide, traditionally used in this type of devices.
The authors of the study, including Yu Han and Jiehao was, underline how this strategy allows to balance the physical and chemical properties of the material, stabilizing the structure of the cell and preventing degradations caused by deep defects and non -desired phase transitions.
Record performance: 25.9% of efficiency and improved duration in complex environmental conditions
The researchers tested this innovation by building a solar cell based on large band -band perovskite CSPBI₂br, which has reached one Power conversion efficiency of 19.2% with a Open circuit voltage of 1.44 V. But the most important result was obtained with the tandem version: one Perovskite/organic solar cell which has reached an efficiency of 25.9%certified to 25.1%keeping performance in variable environmental conditions.
The analysis of the behavior of the materials was conducted with high precision tools such as Tof-Sims, UV-Visible spectroscopy in real time, Scan electronic microscopy (SEM), Photoluminescent mapping (PL) And X -ray X -ray diffraction (GIWAXS). The results confirmed a better crystallization, a more orderly structure and greater resistance to humidity and high temperatures.
This technology, based on Quantic points enriched with magnesiumit could soon be extended to other types of solar cells, opening new perspectives for the large -scale spread of more efficient, long -lasting and accessible photovoltaic devices.
Tandem cells in the world
Innovations on Solar cells tandem perovskite/organic They fit into a constantly evolving global panorama. In China, for example, thePolytechnic University of the North-West of Xi’an has developed a semi-transparent four-term terminal semi-transparent cell tandem, equipped with a protective layer in Indio oxide (in₂o₃). This material improves not only the efficiency, but also the sustainability of the production process, thanks to a method of economic deposition and without solvents.
In Taiwan, the prestigious institute Academia Sinica recently reached an efficiency of the 31.5% With a Tandem perovskite-Silicium-two-term cells. The researchers are already working on a new generation of devices, focusing on large -scale production, increase in the active surface and improvement of operational stability.
On the industrial level, the Chinese Longi currently holds the worldwide efficiency record for cells perovskite-siliciowith an incredible 34.6% reached in 2023. The Kaust In Saudi Arabia he follows with a device from 33.7%.
According to experts of the Fraunhofer Institute for Solar Energy Systems (ISE) In Germany, the theoretical limit for this technology could exceed 39.5% efficiencybut to reach it it will be necessary to rethink some key materials, such as the Fullerene (C60) for the transport of electrons or replace theIndio-Stagno oxide (ito) To increase the transparency of the cells.
