The aim is to conduct R&D for premium high-efficiency product that will be more attractive than a new low-efficiency, thin-film product.
The motivation of the project is to develop tandem solar cell technology with efficiencies (e.g., >30% for silicon perovskite tandem) surpassing the theoretical limit of single junction solar cell (e.g., 29% is the practical limit for Si single junction cell). The aim is to conduct R&D for premium high efficiency product that will be more attractive than a new low-efficiency, thin-film product.
Several strategies for integrating perovskite solar cell with silicon solar cell for high power conversion efficiency have been trialled and were successful. These include spectrum splitting using optical elements to divert high photon energy-sunlight onto the perovskite cell and low-photo energy sunlight onto the silicon cell. Another strategy is the use of perovskite cell itself as a spectrum splitter by reflecting low photo energy sunlight onto the silicon cell while absorbing high photon energy sunlight itself for power conversion.
The third strategy is by mechanically stacking a perovskite cell on top of a silicon cell while independently wiring the cells to produce power output equalling the sum of the outputs of the individual cells. The last strategy is by directly fabricating a perovskite solar cell on top of a silicon cell. The boost in performance is thus a result of the boost in output voltage equalling the sum of the voltages of the individual cells. The last approach which is also called monolithic integration is most elegant reducing complexity associated with wiring and packaging. However, this approach requires careful cell design to achieve low loss interface and to match output currents of the individual cells as they are electrically connected in series. In addition, fabrication processes and architectures of the individual cells need to be compatible with each other.