Dual‐Ion‐Diffusion Induced Degradation in Lead‐Free Cs₂AgBiBr₆ Double Perovskite Solar Cells

Abstract

Lead halide perovskites have witnessed significant progress in low-cost and high-efficiency photovoltaics, with a rapid increase in photovoltaic efficiencies from 3.8% to a certified record of 25.2% in the past decade. [1-4] However, the viability and practical scale-up implementation are limited by the stability and toxicity of the lead halide perovskites. [5,6] To circumvent these two

The Bottlenecks of Cs2AgBiBr6 Solar Cells: How Contacts and Slow Transients Limit the Performance

“…[19,21] Although first solar cell reports were published several years ago with an initial PCE of ≈2.5%, [22] researchers so far have struggled to achieve a PCE exceeding 2.84% by using this material as absorber. [20,[23][24][25][26][27][28][29][30] Besides addressing the possibility to tune the rather large and indirect bandgap and more generally the absorption onset using additives and alloying, [31][32][33][34][35] several studies have focused on the identification of the limiting Cs 2 AgBiBr 6 has attracted much interest as a potential lead-free alternative for perovskite solar cells. Although this material offers encouraging optoelectronic features, severe bottlenecks limit the performance of the resulting solar cells to a power conversion efficiency of below 3%.…”

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

“…[16] Double perovskite materials were first reported during the 1970s but, to date, the optoelectronic properties of only a few formulations (namely, Cs 2 NaBiX 6 and Cs 2 AgBiX 6 )-with more adapted properties for solar cellshave been studied in PV devices. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Cs 2 AgBiBr 6 has an indirect bandgap of 1.95 eV and a direct bandgap of 2.20 eV, which makes the material particularly interesting as wide-gap semiconductor top cell in tandem or even triple junction solar cells. [31] Greul et al first reported Cs 2 AgBiBr 6 films in solar cells.…”

Lead‐Free Halide Double Perovskite Nanocrystals for Light‐Emitting Applications: Strategies for Boosting Efficiency and Stability

“…For instance, Tang group [ 176,177 ] found that Cs 2 AgBiBr 6 showed ionic migration nature due to the major ionic migration channels from bromide vacancies, which was similar to regular mixed halide perovskites. Interestingly, a recent report thought that Cs 2 AgBiBr 6 exhibited a unique dual‐ion‐migration phenomenon, where Ag + and Br − ions gradually diffused through the hole‐transporting layer in the long‐term operation due to the low formation energies of the Ag and Br vacancies, [ 178 ] which was different with halide perovskites. In other words, Cs 2 AgBiBr 6 is prone to phase separation, which results in the formation of AgBr phase due Ag ions and Br ions migration.…”