All-Inorganic CsPb₂I₄Br/CsPbI₂Br 2D/3D Bulk Heterojunction Boosting Carbon-Based CsPbI₂Br Perovskite Solar Cells with an Efficiency of Over 15%

Abstract

The introduction of a two-dimensional (2D) perovskite into a three-dimensional (3D) perovskite has been proven to be effective in minimizing defect state density and improving the performance and stability of the corresponding perovskite solar cells (PSCs). However, it is a challenge to construct a 2D perovskite in 3D inorganic perovskites (CsPbX3, X = halogen) due to the limitation of the annealing temperature or the resistance of Cs+ toward the commonly used organic cation spacer. Here, we propose a strategy for the construction of an all-inorganic 2D/3D CsPb2I4Br/CsPbI2Br bulk heterojunction (BHJ) by the in situ reaction of excess PbI2 in a precursor solution with CsPbI2Br during the annealing process. The formed 2D/3D BHJ effectively passivates the defects at the surface and grain boundaries of 3D CsPbI2Br and reduces the nonradiative recombination loss in the resulting carbon-electrode-based perovskite solar cells (C-PSCs). The open-circuit voltage and efficiency of the champion C-PSCs are boosted to 1.32 V and 15.25%, respectively, which are the best results for CsPbI2Br-based C-PSCs.

Inorganic Framework Composition Engineering for Scalable Fabrication of Perovskite/Silicon Tandem Solar Cells

“…Besides, the inorganic α and δ phases formed after the FHT could act as perovskite seeds that promoted the conversion of inorganic frameworks (Figure S7). Correspondingly, for the TS+FHT framework, the enhanced absorption at 500 nm and the PL peak wavelength around 520 nm both corroborated the band gap of the new phase, which was in good agreement with CsPb 2 X 5 reported in previous reference, as ultraviolet–visible absorption (UV–vis) and photoluminescence (PL) characterizations demonstrated in Figure g. ,,− Subsequently, surface morphology of the frameworks inferred the phase with a bigger cluster size, contributing to the increased surface roughness (Figure S8 and S9).…”

“…CsPb 2 X 5 structure was generated in the TS+FHT framework. To facilitate analysis, we consider the CsPb 2 Br 5 structure as a reference due to its same crystal structure and similar lattice parameters. ,,, The lattice parameters of CsPb 2 Br 5 and PbI 2 were obtained from the CIF card 1 and 2, respectively (Supporting Information). According to the CIF cards, the PbI 2 diffraction peak appeared at 12.6°, corresponding to the (001) plane with a plane spacing of 6.98 Å; while the CsPb 2 X 5 diffraction peak appeared at 11.1°, corresponding to the (002) plane with a plane spacing of 7.96 Å (Table S2).…”

Enhanced comprehensive performance of carbon-based hole-transport-layer-free CsPbI2Br solar cells by a low-cost and stable long chain polymer

“…Therefore, a much superior PCE of 14.27% ( V oc : 1.300 V, J sc : 14.69 mA cm −2 , FF: 74.7%) to that of 11.80% ( V oc : 1.228 V, J sc : 14.30 mA cm −2 , FF: 67.2%) for the control device can be achieved, which is also a higher value among the reported HTL-free carbon-based CsPbI 2 Br PSCs (see Table S4, ESI†). 26,59–67 In addition, for the illuminated J – V curves and the corresponding parameters of the devices prepared with ABS addition of 0.004 and 0.006 mg mL −1 , one can see Fig. S6 (ESI†) and Table 1.…”

Interfacial Treatment by 1,4-Phenyldiammonium Diiodide to Significantly Improve the Performance of Carbon-Based CsPbI2Br Solar Cells

“…With the increase in V , the trap-filled limited (TFL) conductive mechanism dominates the electron transfer, leading to the nonlinear relationship between I and V . The trap density ( n trap ) can be estimated based on the relationship of I and V following n trap = 2ε V TFL /( eL 2 ), in which ε denotes the dielectric constant of CsPbI 2 Br, V TFL is the abscissa of the intersection point by extrapolating the I – V curves in the Ohmic response region and the TFL conductive region as illustrated in Figure c, − e is the elementary charge, and L is the thickness of the CsPbI 2 Br layer. One notes that the PhDADI modification makes n trap reduce from 2.48 × 10 15 to 1.28 × 10 15 cm –3 .…”