Lead-free, formamidinium germanium-antimony halide (FA₄GeSbCl₁₂) double perovskite solar cells: the effects of band offsets

Abstract

We report the numerical simulation of an efficient FA4GeSbCl12 solar cell with a PCE of 22.5%. This study provides novel device design and explanations to understand device physics mainly based on CBO & VBO at ETL/absorber & absorber/HTL interfaces.

The impact of CBz-PAI interlayer in various HTL-based flexible perovskite solar cells: A drift-diffusion numerical study

“…6 a), whereas the FF also diminishes from 84 % to 69 % ( Fig. 6 d), similar to our previous reports [ 15 , 47 , 51 , 52 ]. Noticeably, V oc (1.32–1.24 V) and J sc (25.2–24.6 mA/cm 2 ) reduced a little while adjusting R S, whereas they remained unchanged while varying both R S and R sh .…”

“…In general, the absorber thickness plays a vital role in PSCs, which mainly impacts photon collection and solar cell performance. In addition, in actual solar cells, Schottky, Frenkel and intrinsic point defects (i.e., vacancy & interstitial defects) are usually presented at the surface or interface or grain boundaries, significantly affecting the perovskite absorber material electrical properties [ 47 ]. Therefore, to understand the effect of chosen absorber thickness and defect density (N t ) on FPSC performance, the thickness and N t were simultaneously adjusted from 0.45 μm to 2 μm and from 1 × 10 9 cm −3 to 1 × 10 16 cm −3 , respectively.…”

Bandgap Engineering and Enhancing Optoelectronic Performance of a Lead-Free Double Perovskite Cs2AgBiBr6 Solar Cell via Al Doping

“…In LFHDPs, two bivalent metallic Pb 2+ cations are substituted with one monovalent and one trivalent cation, leading to a modification in the dimensionality within the crystal structure. , Because of its versatility in terms of composition and structure, multiple cation substitution is acknowledged as one of the most effective methods within the context of LFHDPs. The Goldschmidt tolerance factor (GT) and octahedral factors (OF) play essential roles in the quest for appropriate and stable perovskite structures . Among the LFHDPs under examination, only a limited number of perovskite materials have met the necessary criteria for integration into solar cell applications.…”

“…Among the LFHDPs under examination, only a limited number of perovskite materials have met the necessary criteria for integration into solar cell applications. Significantly, Cs 2 AgBiBr 6 has become one of the most widely adopted absorbers in LFHDP solar cells. − …”

“…The above-mentioned consequence for Cs 2 AgBiBr 6 is primarily attributed to its notable characteristics, including a high carrier lifetime, relatively small carrier effective mass, strong moisture stability, and low toxicity. While Cs 2 AgBiBr 6 solar cells have demonstrated a modest power conversion efficiency (PCE) of around 3%, they exhibit highly promising exceptional physicochemical properties such as extended carrier lifetimes, robust elasticity, resistance to thermal expansion, long-term stability, and nontoxicity. − However, Cs 2 AgBiBr 6 also shows several disadvantages, including the presence of prominent surface imperfections, the extensiveness of the electron–phonon interaction, the presence of excitons, and difficulties in the manufacturing process, which are particular issues related to low solubility and the requirement for high-temperature phases. , Despite comprehensive efforts aimed at enhancing solar cell architectures with the film formation and preparation for this material, the efficiency has only managed to reach 2.4%. , The limited efficiency primarily results from the wide bandgap and weak light absorption, while the latter issue arises from the material’s indirect bandgap. To address this challenge, it is necessary to modify the band structure of the material. − Multiple effective strategies have been devised to boost the performance of LFHDPs, including partial substitution at the A-site, B-site, or B″-site, chemical substitution, and the incorporation of heterostructure interfaces.…”