https://english.news.cn/20260716/d278bd9306a24cbda7e42503cf1538db/c.html
https://www.nature.com/articles/s41586-026-10869-x
A novel perovskite-organic tandem solar cell that has set a new world record of 28.04 percent for steady-state photoelectric conversion efficiency. The cell was developed by the CAS Institute of Chemistry.
When integrated with an organic bottom subcell, the laboratory power conversion efficiency of the tandem device peaked at 28.80 percent, with a certified steady-state efficiency of 28.04 percent. The cell also demonstrated remarkable operational stability, retaining 90 percent of its initial efficiency after 625 hours of continuous illumination.
Beyond applications in buildings, transportation and wearable electronics, its exceptional power-to-weight ratio makes it a promising candidate for future space missions, including satellites and space stations, where lighter and more efficient energy sources are critical.
Emerging photovoltaic technologies, particularly perovskite and organic solar cells, have advanced rapidly in recent years. Perovskite-organic tandem solar cells maximize solar spectrum utilization: the perovskite top layer captures visible light while the organic bottom layer absorbs near-infrared light, delivering a theoretical efficiency far surpassing that of single-junction devices. However, a persistent challenge has plagued the top perovskite layer. To absorb sufficient sunlight, the thin film requires the simultaneous incorporation of iodine and bromine. Yet during fabrication or under prolonged illumination, iodide and bromide ions tend to segregate by phase separation, causing a continuous drop in voltage and performance degradation.
To address this problem, the team introduced a photo-transformable additive 4-[3-(trifluoromethyl)-3H-diazirin-3-yl]benzylamine (TDB) into the WBG perovskite precursor solution to establish a two-stage strategy for stabilizing the mixed-halide phase.into the perovskite film. During the initial formation of the perovskite film, TDB acts as a mediator, slowing the swift aggregation of bromide ions and ensuring a homogeneous distribution of iodine and bromine from the outset.
Upon exposure to light, TDB transforms into a new molecular structure, TAB, which anchors at the grain boundaries of the perovskite material. This newly formed molecule effectively suppresses halide ion migration and phase separation, a transformation from being light-averse to light-adaptive.