Belgian research centre Imec has announced that it has boosted the performance of its its 4 cm2 perovskite/silicon tandem photovoltaic module to a power conversion efficiency of 23.9%. According to Imec, this is the first time that a module-on-cell stack structure has outperformed a standalone silicon solar cell.

“Two innovations are key to this achievement,” said group leader for thin-film photovoltaics at imec and perovskite PV program manager at Solliance. “First, a different perovskite material (CsFAPbIBr) was used, largely improving the stability and conversion efficiency of the 4 cm 2 semi-transparent perovskite module to 15.3%. Second, the architecture of the stack was optimized for minimal optical losses by adding an anti-reflection texture on top of the module and a refractive index matching liquid between the perovskite module and the Si solar cell.”

Researchers from Ludwig-Maximilians-Universitaet (LMU) in Munich and the Johannes Kepler University (JKU) in Austria have designed a method to tune the color of the light emitted by a LED by altering the size of its semiconductor crystals.

The method enables the production of semi-conducting nanocrystals of defined size based on perovskites. The crystals are extremely stable, which ensures that the LEDs exhibit high color fidelity – an important criterion of quality. Moreover, the resulting semiconductors can be printed on various surfaces, and are thus promising for the manufacture of LEDs for use in displays.

Researchers from Washington University recently described a novel technique to fabricate perovskite solar cells, using an aerosol-based technique called electrospray deposition.

In the first step, PbI2 is deposited onto a TiO2-coated, fluorine-doped tin oxide glass substrate by spin coating to form a nearly uniform, yellow coating. Next, a solution of methyl ammonium iodide (MAI) is electrosprayed by pumping it through a capillary needle at a high voltage and generating monodispersed charged droplets in Taylor cone-jet mode. The charged droplets travel in the electric field toward the grounded substrate and the solvent from these droplets evaporates before reaching the substrate. The dry MAI nanoparticles then react with the PbI2 layer to form the dark brown colored perovskite. The perovskite formation can be achieved in 40 minutes with optimized MAI concentration, flow rate, and substrate-to-needle distance.