Homogenous Alloys of Formamidinium Lead Triiodide and Cesium Tin Triiodide for Efficient Ideal‐Bandgap Perovskite Solar Cells

Zong, Yanbing; Wang, Ning; Zhang, Lin; Ju, Ming‐Gang; Zeng, Xiao Cheng; Sun, Xiao Wei; Zhou, Yuanyuan; Padture, Nitin P.

doi:10.1002/ange.201705965

Cited by 4 publications

(1 citation statement)

References 42 publications

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“…The smaller size of tin cations compared to lead cations results in decreasing lattice parameter values as tin content increases, as has been observed via shifts in X-ray diffraction peak position with tin content. 42 , 52 , 55 , 56 , 65 , 66 In cases where the lead-only and tin-only perovskite compositions have different crystal structures, a transition between structures must occur at intermediate tin content. In MASn 1– x Pb x I 3 perovskites, a change from the tetragonal structure encountered for lead-rich compositions to a (pseudo)cubic structure at the tin-rich end has been observed to take place at 50% tin content.…”

Section: Bandgap Tunability and Bowingmentioning

confidence: 99%

Optoelectronic Properties of Tin–Lead Halide Perovskites

2021

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Mixed tin–lead halide perovskites have recently emerged as highly promising materials for efficient single- and multi-junction photovoltaic devices. This Focus Review discusses the optoelectronic properties that underpin this performance, clearly differentiating between intrinsic and defect-mediated mechanisms. We show that from a fundamental perspective, increasing tin fraction may cause increases in attainable charge-carrier mobilities, decreases in exciton binding energies, and potentially a slowing of charge-carrier cooling, all beneficial for photovoltaic applications. We discuss the mechanisms leading to significant bandgap bowing along the tin–lead series, which enables attractive near-infrared bandgaps at intermediate tin content. However, tin-rich stoichiometries still suffer from tin oxidation and vacancy formation which often obscures the fundamentally achievable performance, causing high background hole densities, accelerating charge-carrier recombination, lowering charge-carrier mobilities, and blue-shifting absorption onsets through the Burstein–Moss effect. We evaluate impacts on photovoltaic device performance, and conclude with an outlook on remaining challenges and promising future directions in this area.

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Section: Bandgap Tunability and Bowingmentioning

confidence: 99%

Optoelectronic Properties of Tin–Lead Halide Perovskites

2021

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Blinking Beats Bleaching: The Control of Superoxide Generation by Photo‐ionized Perovskite Nanocrystals

2019

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Moisture-or oxidation-induced degradation is am ajor challenge in the advancement of perovskites-based technology.T he oxidation is caused by electron transfer from ap hoto-excited perovskite nanocrystal to oxygen and the formation of superoxide that disintegrates the perovskite structure.I na ir,t he emission intensity of am ethylammonium lead iodide (MAPbI 3 )p erovskite nanocrystal continuously decreases,whereas ananocrystal in argon or apolymer shows exceptionally stable emission intensity.Surprisingly,inair,the emission intensity of ananocrystal with long-lived OFF states completely recovers after the OFF state.T his property,a long with the rate of non-radiative relaxation that exceeds the rate of electron transfer suggest that the perovskiten anocrystals produce and react with superoxidei nt he excited neutral state,b ut not in the ionizeds tate.I no ther words,t he ultrafast non-radiative relaxation in the ionizeds tate hinders electron transfer to oxygen and prevents oxidation of perovskites.Halide perovskites are emerging into ac lass of costeffective semiconductor materials with promising optical and electronic properties [1] for electroluminescent [2] and photovoltaic devices. [3] Despite the exciting power conversion efficiency and the attractive luminescence of perovskites,the major limitation hampering the practical applications of these materials is moisture-and oxygen-sensitive degradation. [4] While investigations are progressing to stabilize perovskites in the humid atmosphere,t he roles of oxygen on the photoluminescence (PL) properties and the structure of perovskites remain controversial.Recently,H aque and co-workers observed oxidative disintegration of aM APbI 3 film into PbI 2 ,C H 3 NH 2 ,I 2 ,a nd H 2 O, [4a] which is based on their original work on superoxide generation by MAPbI 3 . [4b,c] By employing TiO 2 ,they successfully extracted electrons from MAPbI 3 ,m inimized electron transfer to oxygen, and prevented the oxidation of MAPbI 3 . These observations are correlated with the ab initio studies on superoxide generation by MAPbI 3 and the successive reaction of superoxide with the surface Pb ion to disintegrate the leadiodide octahedral structure. [4d] Conversely,superoxide enhances the PL quantum efficiencies of perovskites,which is by the passivation of iodide vacancies and trap states. [5] Forexample, Scheblykin and co-workers reported the photochemical reaction of oxygen to trap states in MAPbI 3 ,r esulting in an enormous enhancement of PL quantum efficiency. [5c,d] Later, Stranks and co-workers [5b] and He and co-workers [5a] independently reported the reaction of superoxide with MAPbI 3 , the passivation of defects by oxides,a nd an enhancement of the PL quantum efficiency.These contradicting reports on the roles of oxygen on the degradation, defect passivation, and quenching as well as enhancement of PL quantum efficiencies of perovskites attract us to investigate the roles of oxygen and electron transfer on the photooxidation of MAPbI 3 nanocrystals at the ensemble a...

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Blinking Beats Bleaching: The Control of Superoxide Generation by Photo‐ionized Perovskite Nanocrystals

2019

View full text Add to dashboard Cite

Moisture‐ or oxidation‐induced degradation is a major challenge in the advancement of perovskites‐based technology. The oxidation is caused by electron transfer from a photo‐excited perovskite nanocrystal to oxygen and the formation of superoxide that disintegrates the perovskite structure. In air, the emission intensity of a methylammonium lead iodide (MAPbI3) perovskite nanocrystal continuously decreases, whereas a nanocrystal in argon or a polymer shows exceptionally stable emission intensity. Surprisingly, in air, the emission intensity of a nanocrystal with long‐lived OFF states completely recovers after the OFF state. This property, along with the rate of non‐radiative relaxation that exceeds the rate of electron transfer suggest that the perovskite nanocrystals produce and react with superoxide in the excited neutral state, but not in the ionized state. In other words, the ultrafast non‐radiative relaxation in the ionized state hinders electron transfer to oxygen and prevents oxidation of perovskites.

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Homogenous Alloys of Formamidinium Lead Triiodide and Cesium Tin Triiodide for Efficient Ideal‐Bandgap Perovskite Solar Cells

Cited by 4 publications

References 42 publications

Optoelectronic Properties of Tin–Lead Halide Perovskites

Optoelectronic Properties of Tin–Lead Halide Perovskites

Blinking Beats Bleaching: The Control of Superoxide Generation by Photo‐ionized Perovskite Nanocrystals

Blinking Beats Bleaching: The Control of Superoxide Generation by Photo‐ionized Perovskite Nanocrystals

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