Temperature dependence of the electrical conductivity of urea and thiourea

Shaaban, S. M.; El-Sayed, B. A.; Shabana, A. A.; Hassan, Ali M.

doi:10.1016/0167-577x(94)90185-6

Cited by 13 publications

(7 citation statements)

References 6 publications

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“…However, its conductivity is still low (3-6 3 10 À8 S/cm). 53 As a result, the thick layer of urea impedes extraction of the photo-generated hole from the perovskite layer. We also found from c-AFM that the conductivity of the ITO glass decreased after spin coating with 108 mM urea solution (Figure S14).…”

Section: Macroscopic Pl and The Role Of Remnant Ureamentioning

confidence: 99%

A Bifunctional Lewis Base Additive for Microscopic Homogeneity in Perovskite Solar Cells

Lee

Bae

Hsieh

et al. 2017

Chem

365

343

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Here, Yang and colleagues introduce an approach to simultaneously controlling grain growth and passivating grain boundaries in perovskite films. The addition of a Lewis base additive to a perovskite precursor solution results in significant enhancement of grain size and reduction in defect density. The additive increases the activation energy to slow down crystal growth and subsequently precipitate at the grain boundary to passivate defects.

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Section: Macroscopic Pl and The Role Of Remnant Ureamentioning

confidence: 99%

A Bifunctional Lewis Base Additive for Microscopic Homogeneity in Perovskite Solar Cells

Lee

Bae

Hsieh

et al. 2017

Chem

365

343

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“…Based on previous reports, when urea is located on the surface of thin films, the charge collection from the chiral OIHP thin films can be significantly hindered by the urea due to its poor electrical conductivity (3−6 × 10 −8 S cm −1 ). 47,59 However, the current mapping profile for the urea-intercalated chiral OIHPs showed a homogeneously distributed bright red color, which stems from the increased tunneling current flow (Figure 5a), while the chiral OIHPs without urea exhibited a very low current in the entire region (Figure 5b). This result implies that the tunneling of electrons was facilitated as the urea was intercalated into the lattice of chiral OIHPs rather than being retained on the surface of thin films.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Tailoring the Time-Averaged Structure for Polarization-Sensitive Chiral Perovskites

Lee

Ahn

et al. 2022

J. Am. Chem. Soc.

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Chiral perovskites have emerged as promising candidates for polarization-sensing materials. Despite their excellent chiroptical properties, the nature of their multiple-quantum-well structures is a critical hurdle for polarization-based and spintronic applications. Furthermore, as the origin of chiroptical activity in chiral perovskites is still illusive, the strategy for simultaneously enhancing the chiroptical activity and charge transport has not yet been reported. Here, we demonstrated that incorporating a Lewis base into the lattice can effectively tune the chiroptical response and electrical properties of chiral perovskites. Through solid-state nuclear magnetic resonance spectroscopic measurements and theoretical calculations, it was demonstrated that the material property manipulation resulted from the change in the time-averaged structure induced by the Lewis base. Finally, as a preliminary proof of concept, a vertical-type circularly polarized light photodetector based on chiral perovskites was developed, exhibiting an outstanding performance with a distinguishability of 0.27 and a responsivity of 0.43 A W–1.

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“…Furthermore, the annealing step of 125 °C for 30 min is insufficient to induce the sublimation of the urea additive; thus, it can be hypothesized that the residual urea hinders the current collection from the perovskite film. While urea can generate a highly polar resonance structure through electron delocalization via π-bond formationthus possibly behaving like a semiconductorits electrical conductivity is still poor (3–6 × 10 –8 S cm –1 ), impairing the electrical properties of perovskite films.…”

Section: Resultsmentioning

confidence: 99%

Multifunctional Self-Combustion Additives Strategy to Fabricate Highly Responsive Hybrid Perovskite Photodetectors

Jang

Kim

et al. 2020

ACS Appl. Mater. Interfaces

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To resolve the inherent trade-off issue between responsivity and detectivity in FA0.9Cs0.1PbI3 perovskite photodetectors, this paper proposes a novel strategy using multifunctional self-combustion additives (urea and ammonium nitrate). During the early stages of crystallization, urea allows for the formation of a strong Lewis complex-derived low-dimensional intermediate phase; this suppresses the formation of perovskite nuclei, while ammonium ions assist the preferred grain growth along the [110] direction. During the high-temperature annealing steps, a self-combusting exothermic reaction occurs between urea as a fuel and NH4NO3 as an oxidizer, through which a locally supplied heat facilitates the removal of residual urea and byproducts. These multifunctional roles of self-combustible additives facilitate the production of high-quality, enlarged grain-structured perovskite films with improved optoelectronic properties, as confirmed by various analyses, including impedance spectroscopy and intensity-modulated photocurrent spectroscopy. The resulting FA0.9Cs0.1PbI3-based photodiode-type photodetectors exhibit outstanding performance, such as a high responsivity (0.762 A W–1) and specific detectivity (over 5.08 × 1013 Jones) at a very low external reverse bias (−0.5 V). Our findings clearly suggest that the multifunctional self-combustion additives strategy could help realize the full potential of FA1–x Cs x PbI3 as a photodiode-type photodetector.

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Temperature dependence of the electrical conductivity of urea and thiourea

Cited by 13 publications

References 6 publications

A Bifunctional Lewis Base Additive for Microscopic Homogeneity in Perovskite Solar Cells

A Bifunctional Lewis Base Additive for Microscopic Homogeneity in Perovskite Solar Cells

Tailoring the Time-Averaged Structure for Polarization-Sensitive Chiral Perovskites

Multifunctional Self-Combustion Additives Strategy to Fabricate Highly Responsive Hybrid Perovskite Photodetectors

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