High-quality perovskite photovoltaics can now be fabricated at room temperature

Researchers at Brown University (Providence, RI) have developed a simple, room-temperature process for fabricating hybrid perovskite photovoltaic cells.¹ The cells have a solar-to-electric power-conversion efficiency (PCE) of up to 15.2%—and an average PCE of 10.1% for cells made of semi-transparent sub-100-nm-thick perovskite films.

Perovskite films are excellent light absorbers and are much cheaper to make than the silicon wafers used in standard solar cells. By last year, perovskite cells had been certified as having more than 20% efficiency. That rapid improvement in performance is promising, and researchers are racing to start using perovskite cells in commercial products.

The Brown University fabrication method involves room-temperature solvent baths to create perovskite crystals, rather than the furnaces used in conventional crystallization methods. The technique produces high-quality crystalline films with precise control over thickness across large areas, and could point the way toward mass-production of perovskite solar cells.

Two solutions

In the technique, a precursor solution is spin-coated onto a substrate and immersed in a bath of a second solvent -- all at room temperature. The result is rapid crystallization of smooth and uniform perovskite films. Thicknesses of from 20 to 700 nm can be produced. The technique could be scaled up to large roll-to-roll processing for manufacturing.

The partially transparent thinner perovskite films could be used to make photovoltaic windows.

Source: http://news.brown.edu/articles/2015/03/perovskite

REFERENCE:

1. Yuanyuan Zhou et al., Journal of Materials Chemistry A (2015); http://dx.doi.org/10.1039/C5TA00477B