Infrared Light Management Using a Nanocrystalline Silicon Oxide Interlayer in Monolithic Perovskite/Silicon Heterojunction Tandem Solar Cells with Efficiency above 25%

Abstract

Perovskite/silicon tandem solar cells are attractive for their potential for boosting cell efficiency beyond the crystalline silicon (Si) single‐junction limit. However, the relatively large optical refractive index of Si, in comparison to that of transparent conducting oxides and perovskite absorber layers, results in significant reflection losses at the internal junction between the cells in monolithic (two‐terminal) devices. Therefore, light management is crucial to improve photocurrent absorption in the Si bottom cell. Here it is shown that the infrared reflection losses in tandem cells processed on a flat silicon substrate can be significantly reduced by using an optical interlayer consisting of nanocrystalline silicon oxide. It is demonstrated that 110 nm thick interlayers with a refractive index of 2.6 (at 800 nm) result in 1.4 mA cm−² current gain in the silicon bottom cell. Under AM1.5G irradiation, the champion 1 cm2 perovskite/silicon monolithic tandem cell exhibits a top cell + bottom cell total current density of 38.7 mA cm−2 and a certified stabilized power conversion efficiency of 25.2%.

Anti‐Oxidizing Radical Polymer‐Incorporated Perovskite Layers and their Photovoltaic Characteristics in Solar Cells

“…The cells, for example, fabricated with perovskite compounds using a mixture cations of methylamine, formamidine, cesium, and rubidium have provided high photovoltaic conversion efficiencies of beyond 20 % owing to their wide light absorption and high‐quality perovskite layer formation . Their facile fabrication processes, light weight and possible flexible structures, and low material costs have also led to discussions on replacing conventional solar cells with these still developing perovskite cells and utilizing them in a tandem configuration . However, the low durability of the perovskite cells derived from the decomposition of perovskite compounds upon exposure to ambient air remains a problematic issue .…”

“…[14][15][16] Their facile fabrication processes, light weight and possible flexible structures, and low material costs have also led to discussions on replacing conventionals olar cells with these still developing perovskite cells and utilizing them in a tandem configuration. [17][18][19][20] However,t he low durability of the perovskite cells derived from the decomposition of perovskite compounds upon exposure to ambient air remains ap roblematic issue. [21,22] Haquea nd co-workersf ound that the degradation of the organo-lead halide perovskite layer in the presence oxygen is an important factor influencing stability.…”

Two‐Terminal Perovskites Tandem Solar Cells: Recent Advances and Perspectives

“…By combining simulations with experiment, they recently presented a monolithic tandem making use of an optically tailored nc‐SiOx:H interlayer via plasma‐enhanced chemical vapor deposition (PECVD). After tuning the optical properties of nc‐SiOx:H layers, the optimized tandem devices delivered a certified efficiency of 25.2%, with J SC of over 19 mA cm −2 in each subcell …”

“…Recently, Chen et al fabricated an ITO recombination layer to connect the perovskite top‐cell and silicon bottom‐cell. For monolithically integrated tandem containing silicon heterojunction (SHJ) solar cells, n + ‐ and p + ‐doped nanocrystalline hydrogenated silicon (nc‐Si:H) as well as nc‐SiOx:H are also good candidates for recombination layers. The highly doped nc‐Si:H recombination layer could be deposited via the low‐temperature plasma‐enhanced CVD process, and it gave rise to higher shunt resistances and improved large‐area performance (18% efficiency on 12.96 cm 2 cell area).…”

Photoinduced Trap Passivation for Enhanced Photoluminescence in 2D Organic–Inorganic Hybrid Perovskites

“…Driven by the remarkable optoelectronic properties, hybrid perovskites have shown great promise for high‐performance functional devices including solar cells, light‐emitting diodes, and photodetectors . In particular, organic–inorganic perovskites have opened up a new territory of solar cells with power conversion efficiency over 25% . As an excellent candidate for optoelectronics, photoinduced effects in organic–inorganic perovskites have attracted increasing attentions due to serious concerns on the stability and lifetime of the optoelectronic devices .…”