Advancement on Lead-Free Organic-Inorganic Halide Perovskite Solar Cells: A Review

Abstract

Remarkable attention has been committed to the recently discovered cost effective and solution processable lead-free organic-inorganic halide perovskite solar cells. Recent studies have reported that, within five years, the reported efficiency has reached 9.0%, which makes them an extremely promising and fast developing candidate to compete with conventional lead-based perovskite solar cells. The major challenge associated with the conventional perovskite solar cells is the toxic nature of lead (Pb) used in the active layer of perovskite material. If lead continues to be used in fabricating solar cells, negative health impacts will result in the environment due to the toxicity of lead. Alternatively, lead free perovskite solar cells could give a safe way by substituting low-cost, abundant and non toxic material. This review focuses on formability of lead-free organic-inorganic halide perovskite, alternative metal cations candidates to replace lead (Pb), and possible substitutions of organic cations, as well as halide anions in the lead-free organic-inorganic halide perovskite architecture. Furthermore, the review gives highlights on the impact of organic cations, metal cations and inorganic anions on stability and the overall performance of lead free perovskite solar cells.

Predictions and Strategies Learned from Machine Learning to Develop High‐Performing Perovskite Solar Cells

“…In general, there are two kinds of PSC architecture: regular (n-i-p) and inverted (p-i-n). [12] Although the structures are different, they follow the common energy conversion processes: i) photon absorption, exciton generation, and exciton dissociation in the perovskite layer, ii) electron and hole transport through ETL and HTL, and iii) a collection of charges at the respective metal/metal oxide electrodes. The device performances depend on optical and electrical properties of the perovskite materials such as bandgap, exciton binding energy, carrier mobility, crystallinity of materials, grain size, the highest occupied molecular orbital (HOMO), and lowest unoccupied molecular orbital Perovskite solar cells (PSCs) have recently received considerable attention due to the high energy conversion efficiency achieved within a few years of their inception.…”

The Role of Chloride Incorporation in Lead‐Free 2D Perovskite (BA)2SnI4: Morphology, Photoluminescence, Phase Transition, and Charge Transport

“…Except for the long‐term environmental stability, the toxicity of lead casts a shadow on the large‐scale perovskite‐based optoelectronic applications in practice in both 2D and 3D perovskite materials . There has been a growing effort to replace lead perovskites with environment‐friendly lead‐free compounds by substituting the divalent lead (Pb) with nontoxic metals including bismuth (Bi), germanium (Ge), and tin (Sn) . Unfortunately, due to the inherent propensity for the oxidation of Sn 2+ to Sn 4+ , which creates a high defect density and hence lability, 3D Sn‐based perovskite materials undergo rapid degradation and thus show poor reproducibility even prepared in a glovebox with trace amounts of water and oxygen .…”

Structural and optical properties of 2D Ruddlesden‐Popper perovskite (BA)2(FA)n−1PbnI3n+1 compounds for photovoltaic applications

“…The crystal information calculated from the XRD patterns is summarized in Table , showing that (BA) 2 (FA) n−1 Pb n I 3n+1 perovskites have orthorhombic phases, with α = β = γ = 90°C, and b = 28.2935, 40.3157, 52.5491 and 64.9287 Å for n = 1, 2, 3, 4. The (BA) 2 (FA) 3 Pb 4 I 13 perovskite had larger b value of crystal parameters than (BA) 2 (MA) 3 Pb 4 I 13 because the large FA + cation may have expanded the unit cell of the Ruddlesden‐Popper structures . The high‐angle diffractions of BF‐DMSO and BF‐DMF are shown in Figures C,D, in which the peaks are more likely related to trigonal FAPbI 3 with α = β = 90°C, γ = 120°C, and a = b = 8.8436 Å, c = 11.0875 Å.…”

“…Liu et al ascribed the crystal structure and orientation variation to the formation of Lewis acid‐base adducts when DMF was replaced by DMSO in the precursors . The mechanism of solvent effect on powder and thin film process was unclear but is possibly related to the rapid evaporation of solvents with different boiling points on the hotplate . The surface SEM images of the BF‐DMSO‐n films are also shown in Figure .…”