High Efficiency Perovskite‐Silicon Tandem Solar Cells: Effect of Surface Coating versus Bulk Incorporation of 2D Perovskite

Abstract

Mixed‐dimensional perovskite solar cells combining 3D and 2D perovskites have recently attracted wide interest owing to improved device efficiency and stability. Yet, it remains unclear which method of combining 3D and 2D perovskites works best to obtain a mixed‐dimensional system with the advantages of both types. To address this, different strategies of combining 2D perovskites with a 3D perovskite are investigated, namely surface coating and bulk incorporation. It is found that through surface coating with different aliphatic alkylammonium bulky cations, a Ruddlesden–Popper “quasi‐2D” perovskite phase is formed on the surface of the 3D perovskite that passivates the surface defects and significantly improves the device performance. In contrast, incorporating those bulky cations into the bulk induces the formation of the pure 2D perovskite phase throughout the bulk of the 3D perovskite, which negatively affects the crystallinity and electronic structure of the 3D perovskite framework and reduces the device performance. Using the surface‐coating strategy with n‐butylammonium bromide to fabricate semitransparent perovskite cells and combining with silicon cells in four‐terminal tandem configuration, 27.7% tandem efficiency with interdigitated back contact silicon bottom cells (size‐unmatched) and 26.2% with passivated emitter with rear locally diffused silicon bottom cells is achieved in a 1 cm2 size‐matched tandem.

Triple-cation low-bandgap perovskite thin-films for high-efficiency four-terminal all-perovskite tandem solar cells

“…CL is a suitable characterization technique to detect phase segregations and residual materials such as PbI 2 excess in perovskite thin-lms. [66][67][68][69] We compare CL spectra of LBG perovskite thin-lms with different Cs concentrations within the spectral range from 400 to 900 nm ( Fig. 3a).…”

Perovskite‐Based Tandem Solar Cells: Get the Most Out of the Sun

“…[53,112] Moreover, the highest efficiency of 4T configurations so far is also obtained by mixed-cation perovskite, i.e., Rb 0.05 Cs 0.095 MA 0.1425 F A 0.7125 PbI 2 Br/IBC c-Si TSC with a PCE of 27.7%. [18] To grasp a general picture of the state-of-the-art development of 2T TSCs and to find the general relationships among the real (not theoretical) device parameters, we made manual data mining based on the data of almost all the 2T perovskite/Si, 2T perovskite/CIGS and 2T perovskite/perovskite TSCs reported so far (Tables 1-3). If we assume that the bottom absorbers (Si or CIGS) of these cells have the same bandgap (≈1.2 eV), then we may visualize the interdependent links among the J sc , V oc , absorbers thicknesses (T top and T bottom ) and bandgap values of the two subcells (B top and B bottom ).…”

“…As shown in Figure 3, efficiencies of all types of TSCs are advancing considerably in a few short years. So far, the highest efficiencies of monolithic two-terminal (2T or monolithic) TSCs and mechanically stacked 4T TSCs have reached 27.0% and 27.7%, [17,18] respectively, exhibiting huge potentiality in possible applications in the consumption area.…”

A High‐Performance and Long‐Term Air‐Stable CH3NH3PbI3/C8BTBT Heterojunction Photodetector Fabricated via Chemical Vapor Deposition

“…Since 2009, the power conversion efficiencies (PCEs) of organic–inorganic hybrid perovskite solar cells have been improved substantially, and their manufacturing procedures are continuously optimized. [ 15,16 ] In particular, the perovskite photodetector has also developed rapidly. [ 17,18 ] In recent years, many valuable studies have been conducted that focus on the construction of heterostructures with the goal to improve the performance of perovskite photodetectors.…”