Multimodal Microscale Imaging of Textured Perovskite–Silicon Tandem Solar Cells

Abstract

Halide perovskite/crystalline silicon (c-Si) tandem solar cells promise power conversion efficiencies beyond the limits of single-junction cells. However, the local light-matter interactions of the perovskite material embedded in this pyramidal multijunction configuration, and the effect on device performance, are not well understood. Here, we characterize the microscale optoelectronic properties of the perovskite semiconductor deposited on different c-Si texturing schemes. We find a strong spatial and spectral dependence of the photoluminescence (PL) on the geometrical surface constructs, which dominates the underlying grain-to-grain PL variation found in halide perovskite films. The PL response is dependent upon the texturing design, with larger pyramids inducing distinct PL spectra for valleys and pyramids, an effect which is mitigated with small pyramids. Further, optimized quasi-Fermi level splittings and PL quantum efficiencies occur when the c-Si large pyramids have had a secondary smoothing etch. Our results suggest that a holistic optimization of the texturing is required to maximize light in- and out-coupling of both absorber layers and there is a fine balance between the optimal geometrical configuration and optoelectronic performance that will guide future device designs.

Imaging and quantifying non-radiative losses at 23% efficient inverted perovskite solar cells interfaces

“…In order to better assess the homogeneity of the passivation over the samples surface, we mapped the optoelectronic properties by spectrally and temporally resolved photoluminescence imaging analysis on the full stack without the silver rear electrode. We first fitted the PL spectra pixel-by-pixel 39 , 42 by using the model proposed by Katahara and Hillhouse 43 , 44 to extract key physical parameters like the bandgap energy ( E g ), the quasi-Fermi levels splitting (Δμ or QFLS) and the Urbach energy ( E u ) from absolutely calibrated spectral images. More details on the fitting model are provided in the Supplementary Information section.…”

Nano-optical designs enhance monolithic perovskite/silicon tandem solar cells toward 29.8% efficiency

“…Nonetheless, the overall high level of optical performance was independently confirmed by the EQE calculated from the relative spectral response measurements at Fraunhofer ISE CalLab (see Fig. S4a,b S5) 15,18,20 .…”

“…However, they are not compatible with solutionprocessed perovskite absorbers without further adaptation. In recent years, different approaches to implement light management textures in PSTSC were investigated, either by adapting the perovskite deposition technique but leaving the pyramidal texture unchanged [15][16][17][18][19][20] with maximum PCE of 27.4% 20 , or by adapting the pyramidal textures such that perovskite solution-processing becomes feasible 10,[21][22][23][24][25] leading to a maximum PCE of 28.6% 25 (Fig. S1).…”

Monolithic perovskite/c-Si tandem solar cell: Progress on numerical simulation

“…The issue of light propagation and absorption in solar cells is ultimately a problem of solving electromagnetic field, for which there are many numerical methods, as shown in Table 1. The relatively mature kernels of simulation software are: FEM [64,65], MoM [66], which belong to frequency domain technique; FDTD [62,63,[67][68][69][70][71], TMM [72][73][74][75], and TDIE [76], which belong to time domain technique. Each method has its own features and limitations.…”

“…This invited review summarizes the progress of numerical simulation studies of PSK/c-Si TSC in terms of the methodology, light harvesting management, and energy yield (EY) aspects. Starting with the physical fundamentals of the methodology, we outline five commonly used software kernels (finite element method (FEM) [64,65], method of moments (MoM) [66], finite difference time domain (FDTD) [62,63,[67][68][69][70][71], transfer matrix method (TMM) [72][73][74][75], and time domain integral equation (TDIE) [76]) for calculating electromagnetic problems, and point out that integration of methods, optimization of modeling and parameter correction can effectively improve simulation accuracy. For the light harvesting management part, by analyzing the optical properties of single junction cell, double junction cell and quasi-conformal structure, we illustrate that the textured PSK/c-Si TSC has excellent PV performance.…”