An extensive study on multiple ETL and HTL layers to design and simulation of high-performance lead-free CsSnCl3-based perovskite solar cells

Abstract

Cesium tin chloride (CsSnCl₃) is a potential and competitive absorber material for lead-free perovskite solar cells (PSCs). The full potential of CsSnCl₃ not yet been realized owing to the possible challenges of defect-free device fabrication, non-optimized alignment of the electron transport layer (ETL), hole transport layer (HTL), and the favorable device configuration. In this work, we proposed several CsSnCl₃-based solar cell (SC) configurations using one dimensional solar cell capacitance simulator (SCAPS-1D) with different competent ETLs like indium-gallium-zinc-oxide (IGZO), tin-dioxide (SnO₂), tungsten disulfide (WS₂), ceric dioxide (CeO₂), titanium dioxide (TiO₂), zinc oxide (ZnO), C₆₀, PCBM, and HTLs of cuprous oxide (Cu₂O), cupric oxide (CuO), nickel oxide (NiO), vanadium oxide (V₂O₅), copper iodide (CuI), CuSCN, CuSbS₂, Spiro MeOTAD, CBTS, CFTS, P3HT, PEDOT:PSS. Simulation results revealed that ZnO, TiO₂, IGZO, WS₂, PCBM, and C₆₀ ETLs-based halide perovskites with ITO/ETLs/CsSnCl₃/CBTS/Au heterostructure exhibited outstanding photoconversion efficiency retaining nearest photovoltaic parameters values among 96 different configurations. Further, for the six best-performing configurations, the effect of the CsSnCl₃ absorber and ETL thickness, series and shunt resistance, working temperature, impact of capacitance, Mott-Schottky, generation and recombination rate, current-voltage properties, and quantum efficiency on performance were assessed. We found that ETLs like TiO₂, ZnO, and IGZO, with CBTS HTL can act as outstanding materials for the fabrication of CsSnCl₃-based high efficiency (η ≥ 22%) heterojunction SCs with ITO/ETL/CsSnCl₃/CBTS/Au structure. The simulation results obtained by the SCAPS-1D for the best six CsSnCl₃-perovskites SC configurations were compared by the wxAMPS (widget provided analysis of microelectronic and photonic structures) tool for further validation. Furthermore, the structural, optical and electronic properties along with electron charge density, and Fermi surface of the CsSnCl₃ perovskite absorber layer were computed and analyzed using first-principle calculations based on density functional theory. Thus, this in-depth simulation paves a constructive research avenue to fabricate cost-effective, high-efficiency, and lead-free CsSnCl₃ perovskite-based high-performance SCs for a lead-free green and pollution-free environment.

Figure 1

(a) Design configuration of the CsSnCl₃-based PSC, and (b) the optimized crystal structure of CsSnCl₃ perovskite.

Figure 2

The electronic (a) band structure and (b) DOS of halide perovskite, CsSnCl₃, (c) and (d) The mapping images of electron density difference in the (110) and (001) planes for halide perovskite, CsSnCl₃, (e) and (f)The Fermi surface topology of CsSnCl₃ perovskite along (001) plane of two different orientations in the same Brillouin zone direction.

Figure 3

Photon energy dependency of (a) dielectric function, (b) refractive index and (c) reflection coefficient; and (d) absorption coefficient, (e) photoconductivity and (f) loss function for halide perovskite, CsSnCl₃ along (110) plane.

Figure 4

Optimization of CsSnCl₃ on PSC characteristics, i.e., V_OC (V), J_SC (mA/cm²), FF (%) and PCE (%) for various HTLs with Au as back metal contact and ETLs: (a) PCBM, (b) TiO₂, (c) ZnO, (d) C₆₀, (e) IGZO, and (f) WS₂.

Figure 5

Band diagram of six optimized devices of CsSnCl₃ with ETLs (a) C₆₀, (b) IGZO, (c) PCBM, (d) TiO₂, (e) WS₂, (f) ZnO.

Figure 6

Energy level alignment of the related (a) ITO, ETLs, and absorber CsSnCl₃, and (b) HTLs.

Figure 7

Effect of (a) J–V, and (b) QE for six studied devices.

Figure 8

Contour mapping of V_OC for CsSnCl₃ absorber and ETLs (a C₆₀, b IGZO, c PCBM, d TiO₂, e WS₂, and f ZnO) thickness.

Figure 9

Contour mapping of J_SC for CsSnCl₃ absorber thickness and ETLs (a C₆₀, b IGZO, c PCBM, d TiO₂, e WS₂, and f ZnO) thickness.

Figure 10

Contour mapping of FF for CsSnCl₃ absorber thickness and ETLs (a C₆₀, b IGZO, c PCBM, d TiO₂, e WS₂, and f ZnO) thickness.

Figure 11

Contour mapping of PCE for CsSnCl₃ absorber thickness and ETLs (a C₆₀, b IGZO, c PCBM, d TiO₂, e WS₂, and f ZnO) thickness.

Figure 12

Effect of R_S on (a) V_OC; (b) J_SC; (c) FF; (d) PCE at an R_SH = 10⁵ Ω cm².

Figure 13

Effect of R_SH on (a) V_OC; (b) J_SC; (c) FF; (d) PCE at an R_S = 0.5 Ω cm².

Figure 14

Effect of the variation in temperature from 275 to 475 K on (a) V_OC; (b) J_SC; (c) FF; and (d) PCE.

Figure 15

(a) The capacitance–voltage (C–V) response, (b) Mott-Schottky (1/C²) response, (c) generation rate, (d) recombination rate for absorber CsSnCl₃-based heterostructures with six different ETLs.