Latest research in solar cells have discovered a way to combine emerging solar-harvesting technology of perovskites with the commercial gold standard — silicon solar cells. The success of the study has led to the invention of a highly efficient and stable tandem solar cell, which achieved an efficiency of 25.7 per cent, the highest to date.
The team of researchers from the University of Toronto Engineering and King Abdullah University of Science and Technology (KAUST) have thus contributed groundbreaking discovery in perovskite technology to create high perfomance photovoltaic panels.
In wake of the recent announcement, Professor Ted Sargent, senior author of the study commented that silicon solar cells are less costly and more efficient today. There are however limitations to its capability, the team is therefore focusing to overcome these with the help of tandem (two-layer) approach.
Study explains, like silicon, perovskite crystals can help absorb solar energy and stimulate electrons which can further be channeled into a circuit. Unlike silicon, perovskites can be combined with liquids in order to create ‘solar ink’ which can be printed on surfaces.
Known as solution processing, the ink-based manufacturing approach has found its feet in the printing industry and therefore has the potential to minimize the cost of making solar cells.
Furthermore, Yi Hou, postdoctoral fellow and lead author, also determined that addition of a layer of perovskite crystals on top of textured silicon in order to create a tandem solar cell further helps in enhancing the performance. However the current research uses thin sheets of crystalline silicon- wafers. The uneven surface of these further reduces the amount of light reflected off the surface of the silicon and augments the overall efficiency. It however is difficult to coat a uniform layer of perovskites on top.
The latest study increased the thickness of the perovskite layer, making it high enough to cover both the peaks and valleys created by the pyramidal structures. This type of charge separation proved advantageous because it increased the charges which flowed into the circuit rather than in other parts of the cell.