High-Efficiency Polycrystalline Thin Film Tandem Solar Cells

Abstract

A promising way to enhance the efficiency of CIGS solar cells is by combining them with perovskite solar cells in tandem devices. However, so far, such tandem devices had limited efficiency due to challenges in developing NIR-transparent perovskite top cells, which allow photons with energy below the perovskite band gap to be transmitted to the bottom cell. Here, a process for the fabrication of NIR-transparent perovskite solar cells is presented, which enables power conversion efficiencies up to 12.1% combined with an average sub-band gap transmission of 71% for photons with wavelength between 800 and 1000 nm. The combination of a NIR-transparent perovskite top cell with a CIGS bottom cell enabled a tandem device with 19.5% efficiency, which is the highest reported efficiency for a polycrystalline thin film tandem solar cell. Future developments of perovskite/CIGS tandem devices are discussed and prospects for devices with efficiency toward and above 27% are given.

High Photoluminescence Quantum Yield in Band Gap Tunable Bromide Containing Mixed Halide Perovskites

“…13,14 As a result, perovskites are not only attractive for the use in single junction solar cells, which have been demonstrated with certified efficiencies above 20%, 15,16 but also promising candidates for application as the top cell in tandem devices, for example in combination with Si [17][18][19] or Cu(In,Ga)Se 2 . 19,20 Moreover, they offer desirable properties for use as light emitting devices such as LEDs 21,22 and lasers gain media. 13,23 Specifically, for the case of tandem photovoltaic devices with a Si bottom cell (E g = 1.12 eV), ideally a top cell with a band gap of ~1.65 -1.9 eV should be employed to reach efficiencies close to ~35% under 1-sun AM1.5G illumination.…”

Solution-processed chalcopyrite–perovskite tandem solar cells in bandgap-matched two- and four-terminal architectures

“…Promising results have already been obtained with MoO3/ITO, nanoparticles/ITO, MoO3/Al:ZnO, Ag nanowires, or thin metal layers. 16,17,[29][30][31][32] Several tandem devices with HP top cells and Si bottom cells have been reported to date with PCEs up to 25.2% for four-terminal and 21.2% for monolithic devices. [32][33][34] But while these efficiencies are very exciting, the use of silicon for the bottom cell imposes restrictions due to silicon's relatively high bandgap of 1.14 eV, limitation to rigid substrates due to the use of monocrystalline Si wafers, and high fabrication cost of the latter.…”

Analysing the Prospects of Perovskite Solar Cells within the Purview of Recent Scientific Advancements

“…TSCs include perovskite along with Kesterite (Cu 2 ZnSn(S,Se) 4 ) [112], crystalline silicon [113][114][115][116], Copper Indium Gallium Selenide [117], and recently even perovskite with perovskite [118] where it was pointed out that there was need for high-performance low bandgap perovskite solar cells. A recent field which is also progressing is polymer-based organic photovoltaic cells which enable solution-processable tandem solar cells [119].…”