Effect of Silicon Surface for Perovskite/Silicon Tandem Solar Cells: Flat or Textured?

Abstract

Perovskite and textured silicon solar cells were integrated into a tandem solar cell through a stacking method. To consider the effective structure of silicon solar cells for perovskite/silicon tandem solar cells, the optic and photovoltaic properties of textured and flat silicon surfaces were compared using mechanical-stacking-tandem of two- and four-terminal structures by perovskite layers on crystal silicon wafers. The reflectance of the texture silicon surface in the range of 750-1050 nm could be reduced more than that of the flat silicon surface (from 2.7 to 0.8%), which resulted in increases in average incident photon to current conversion efficiency values (from 83.0 to 88.0%) and current density (from 13.7 to 14.8 mA/cm). Using the texture surface of silicon heterojunction (SHJ) solar cells, the significant conversion efficiency of 21.4% was achieved by four-terminal device, which was an increase of 2.4% from that of SHJ solar cells alone.

Low‐Bandgap Mixed Tin‐Lead Perovskites and Their Applications in All‐Perovskite Tandem Solar Cells

“…Current densities of two subcells are expected to be almost the same since the total output is determined by the smaller one. Therefore, collaborative optimization among bandgaps, film thickness, light trapping structure, and interconnecting layers should be conducted in 2‐T tandem devices …”

Light Management in Monolithic Perovskite/Silicon Tandem Solar Cells

“…For a planar configuration in TSCs, even after optimization of the bandgaps and layer thicknesses in the perovskite top cell, there are still considerable current losses originating from the reflection, even up to 7 mA cm −2 , as indicated by Chen et al and Jäger et al In silicon solar cells and modules, the surfaces or interfaces are typically textured to reduce reflection losses via enhancing light coupling and scattering and then increasing the average path length in the absorbers . These light trapping technologies can also be suitable for perovskite/silicon TSCs …”

“…As we have known, perovskite material exhibits a quite high photon‐absorption coefficient, whereas that of crystalline silicon is relatively low because silicon is an indirect semiconductor. Therefore, light trapping engineering is more important for silicon to increase the quantum efficiency and short‐circuit current when it is utilized as a bottom cell in a TSC . Even though several nanostructures of perovskite have been reported to enhance light absorption in PSCs as well as perovskite/silicon TSCs, in this Review the more common silicon nanostructures will be mainly discussed in detail.…”

Transparent Electrodes Consisting of a Surface‐Treated Buffer Layer Based on Tungsten Oxide for Semitransparent Perovskite Solar Cells and Four‐Terminal Tandem Applications

“…[ 3–10 ] High efficiency, low material cost, and simple solution processing make PSCs a highly promising source of sustainable energy as either single‐junction devices or in tandem structures on top of other solar cells with narrower band gap absorbers, such as silicon, chalcogenides, and Sn‐containing materials. [ 11–20 ] In particular, further improvement of silicon solar cell efficiencies through silicon‐perovskite tandems is realistic business models, considering that over 90% of the photovoltaic market is dominated by single‐junction silicon solar cells. [ 21 ]…”