Recent Advances in Cs₂AgBiBr₆-Based Halide Double Perovskites as Lead-Free and Inorganic Light Absorbers for Perovskite Solar Cells

Abstract

Although lead-based inorganic–organic perovskite solar cells (PSCs) have delivered the highest power conversion efficiency (PCE) to date of 25.2%, the toxic nature of lead and poor stability are the biggest hurdles for the commercialization of PSCs. Lead-free halide double perovskite Cs2AgBiBr6 has received increasing attention as a promising alternative for toxic and unstable organic–inorganic perovskites in PSCs due to its nontoxicity, high structural stability, and unique photoelectric properties. However, the PCEs of Cs2AgBiBr6-based PSCs are strongly restricted by the inherent and extrinsic defects in Cs2AgBiBr6 films. Thus, an in-time review to summarize the research progress of Cs2AgBiBr6-based PSCs to provide strategies for the enhancement of PCEs is critical. In this review, the recent advances in Cs2AgBiBr6 as a light absorber in PSCs are summarized and discussed with an emphasis on the structural, photoelectric, and physical properties of Cs2AgBiBr6. The synthesis and fabrication methods of Cs2AgBiBr6 crystals and films are also reviewed. Importantly, strategies for improving the photovoltaic performance of Cs2AgBiBr6-based PSCs are presented, including band gap engineering, film quality optimization, and interface engineering. Finally, current challenges and perspectives are presented. This review aims to provide useful guidelines for future research in this emerging field.

Spray‐Coated Lead‐Free Cs2AgBiBr6 Double Perovskite Solar Cells with High Open‐Circuit Voltage

“…[7,8] This is why many research groups focus-through theoretical and/or experimental studies-on the development of lead-free perovskite materials. [9][10][11][12][13][14][15] To diminish the amount of lead in perovskite PV absorber, two options are generally envisaged: the first is to replace a fraction of lead by a non-hazardous metal cation; the second is to completely substitute lead by a nontoxic element such as Ge(II), Mn(II), Cu(II), Bi(III), or Sb(III). [10] Lead-free halide double perovskites are considered as one of the promising PV absorber alternatives to lead halide perovskite in view of their nontoxic character and long-term stability.…”

Phase Transitions in Low-Dimensional Layered Double Perovskites: The Role of the Organic Moieties

“… 4 In this respect, the substitution of Pb 2+ by the combination of trivalent (Bi 3+ , Sb 3+ ) and monovalent (Ag + , Cu + , Au + , K + ) cations leads to the formation of double perovskites, which demonstrated ambient stability but inferior device performance compared with Pb-halide perovskites. 4 , 7 , 8 The Cs 2 AgBiBr 6 double perovskite has demonstrated good performance in solar cells, reaching a PCE of 2.84%, 9 − 15 and in photodetectors, with detectivity of 3.29 × 10 12 Jones and fast response of 17 ns. 16 Additionally, it has been applied in X-ray detectors 17 and memristors.…”

Recycling lead and transparent conductors from perovskite solar modules

“…However, most efficient metal halide perovskites for this purpose contain toxic lead, such as α-FAPbI 3 11 , 12 , (FAPbI 3 ) 0.95 (MAPbBr 3 ) 0.05 13 , MA x FA 1−x PbI 3 14 , 15 , etc. Although there have been extensive attempts to replace lead in MHPs, all current lead-free perovskite solar cells suffer from either much poorer stability, such as the tin-based perovskite solar cells 16 , 17 , or much lower efficiency, such as double-perovskite-based solar cells 18 , compared with their lead-based counterparts. One gigawatt of solar PV capacity using perovskite solar panels with efficiency of 20% would contain ~3.5 tons of lead using the best-known perovskite materials as listed above, assuming a perovskite film thickness of 500 nm.…”