Investigating ultrafast carrier dynamics in perovskite solar cells with an extended π-conjugated polymeric diketopyrrolopyrrole layer for hole transportation

Kulshreshtha, Chandramouli; Clement, Arul; Pascher, Torbjörn; Sundström, Villy; Matyba, Piotr

doi:10.1039/c9ra10009a

Cited by 7 publications

(9 citation statements)

References 33 publications

(45 reference statements)

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“…This small PA peak could be interpreted as absorption by exciton species or hot carriers as previously reported. ,, As shown in Figures a and S13, there were slight bleaching signals around 900–950 nm in the NIR region. The bleaching signal at 900–950 nm was excluded from the analysis because the critical region overlapped with the probing laser; however, this has been reported as trap states. , The PA hole peaks shifted from 1000 to 1200 nm, depending on the thickness of the NiO HTL. The PA hole spectrum was longer than 1000 nm with or without the HTLs.…”

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confidence: 99%

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Unusual Hole Transfer Dynamics of the NiO Layer in Methylammonium Lead Tri-iodide Absorber Solar Cells

Yang

Park

Kim

et al. 2021

J. Phys. Chem. Lett.

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Nickel oxides (NiO) as hole transport layers (HTLs) in inverted-type perovskite solar cells (PSCs) have been widely studied mainly because of their high stability under illumination. Increases in the power conversion efficiency (PCE) with NiO HTLs have been presented in numerous reports, although the photoluminescence (PL) quenching behavior does not coincide with the PCE increase. The dynamics of the charge carrier transport between the NiO HTLs and the organic−inorganic halide perovskite absorbers is not clearly understood yet and quite unusual, in contrast to organic/polymerics HTLs. We deposited NiO HTLs with precisely controlled thicknesses by atomic layer deposition (ALD) and studied their photovoltaic performances and hole transfer characteristics. Ground state bleaching (GSB) recovery was observed by ultrafast transient absorption spectroscopy (TAS), which suggested that backward hole injection occurred between the perovskites and NiO HTLs, so that the uncommon PL behaviors can be clearly explained. Backward hole injection from the NiO HTL to the perovskite absorber originated from their similar valence band (VB) energy positions. The thickness increase of the NiO HTLs induced VB sharing, which caused a red-shift of the photoinduced hole absorption spectrum in near-infrared (NIR) femtosecond TAS and a decrease in the PL intensity. Our studies on inorganic metal oxide transport layers, NiO in this work, with a thickness dependence and the comparison with organic layers provide a better understanding of the interfacial carrier dynamics in PSCs.

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confidence: 99%

“…The bleaching signal at 900−950 nm was excluded from the analysis because the critical region overlapped with the probing laser; however, this has been reported as trap states. 51,52 The PA hole peaks shifted from 1000 to 1200 nm, depending on the thickness of the NiO HTL. The PA hole spectrum was longer than 1000 nm with or without the HTLs.…”

mentioning

confidence: 99%

Unusual Hole Transfer Dynamics of the NiO Layer in Methylammonium Lead Tri-iodide Absorber Solar Cells

Yang

Park

Kim

et al. 2021

J. Phys. Chem. Lett.

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“…TA spectroscopy of PSCs is usually focused on the visible (VIS) region in which the main perovskite material signal appears. However, the near-infrared (NIR) range can deliver useful information about the cell operation due to the presence of the oxidized forms of the hole-transport material molecules (e.g., spiro-OMeTAD) − and charge carrier interband transitions . Unfortunately, it has been also reported that the NIR spectra suffer from interference signals caused by photoinduced refractive index changes in a perovskite material, , which can make it extremely hard to untangle the information required.…”

Section: Introductionmentioning

confidence: 99%

Complete Perovskite Solar Cells with Gold Electrodes Studied in the Visible and Near-Infrared Ranges

2022

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Complete solar cells with the triple-cation perovskite (FA 0.76 MA 0.19 Cs 0.05 Pb(I 0.81 Br 0.19 ) 3 ) sandwiched between spiro-OMe-TAD (2,2′,7,7′-tetrakis-(N,N-di-4methoxyphenylamino)-9,9′-spirobifluorene) and mesoporous titania layers were examined using femtosecond transient absorption (TA) and steady-state absorption in the visible and near-infrared (NIR) regions. We demonstrate in this paper that the transmission spectroscopic measurements through a gold layer are possible and open the way to investigate the solar cells in working conditions (with applied voltage and/or additional illumination). We show that a gold electrode does not exhibit a significant TA signal itself but causes a difference in the perovskite response at around 800 nm and in the NIR range. The irradiation with a femtosecond laser, 1 Sun stationary illumination, or applied voltage causes significant changes in the TA spectra and kinetics at the TiO 2 interface, most probably due to ion segregation or ion rearrangement process. The transmission signal in the NIR range is shown to be dominated by spectral modulation due to light interference; however, the process of hole injection at spiro-OMeTAD interfaces can be extracted. Finally, application of an appropriate forward bias enables the suppression of electron and hole injection to contact materials and results in increased lifetime of charge population in the perovskite.

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“…Yang et al fabricated highly potent, inexpensive, and stable devices utilizing perovskite films reformed and passivated by functional polymers, such as poly(4-vinylpyridine) . Grätzel’s group demonstrated that the hydrophobic species 1-adamantylamine and its halide derivatives are impactful agents for perovskite/HTL modification and can achieve outstanding device efficiency with good moisture and operational stability via readily antisolvent or solution methods. , Several other polymer molecules, like polystyrene or poly(ethylene oxide), were also employed to function as a defect passivation/water screening interlayer between the perovskite and the ETL/HTL. , …”

Section: Introductionmentioning

confidence: 99%

“…22,23 Several other polymer molecules, like polystyrene 24 or poly(ethylene oxide), 25 were also employed to function as a defect passivation/water screening interlayer between the perovskite and the ETL/HTL. 26,27 However, in most cases, the polymer dopants tend to be utilized as additives or interlayers and exhibit relative single function attributable to the constraint devised by the simple molecule structure. It will be further beneficial if the polymerbased interfacial technology effectuates defect passivation, morphology enhancement, and water screening in an integrated manner simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Bifunctional Interfacial Modification Engineering with Biomimetic Perfluoro-Copolymer-Enabled High-Efficiency and Moisture-Resistant Perovskite Solar Cells

Qian

Yang

Zhang

et al. 2020

ACS Appl. Electron. Mater.

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In recent years, interfacial technology encompassing attributes such as defect passivation and stability enhancement of perovskite solar cells (PSCs) has captivated the solar research fraternity with their power conversion efficiency (PCE) being as high as 25.5%. In accordance with the theory of compounding two functional groups integrally into a single structure under relatively moderate formation conditions, this paper presents an efficacious interfacial passivation modification strategy for PSCs with well-controlled morphologies and passivated charged surface states using a bidentate ligand perfluorocarbon copolymer (PFOMA). The strategy involves self-assembly of biomimetic PFOMA on a perovskite surface due to the coordination binding between the catecholic OH groups of PFOMA and Pb2+ . The time-resolved photoluminescence measurements demonstrated that the effective passivation of catecholic OH groups benefits from the inhibition of the photogenerated carrier recombination. Furthermore, the long fluorocarbon alkyl chains of PFOMA bestow the perovskite surface with higher resistance against moisture. Hence, the resulting PFOMA-modified PSC can accomplish an above-average efficiency of about 20.66% (with an average PCE of 19.71%) with a notable increment in the open-circuit voltage of about 40 mV compared to the control voltage (1.12 mV). Particularly, the PFOMA-modified PSC exhibits a remarkable enhancement in the moisture stability factor under a relative humidity of 70 ± 5%, retaining >90% of their initial efficacies along with considerably upgraded device performance (an average PCE of 19.71% and a champion device PCE of 20.66% were achieved) and an enhanced moisture stability factor even under a relative humidity of 70 ± 5%. The highly proficient passivation strategy demonstrated in this work can help the future exploration of this function-oriented synthesis strategy and can pave the path for the universal application of PSCs employing the modification of polymers and more organic species.

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Investigating ultrafast carrier dynamics in perovskite solar cells with an extended π-conjugated polymeric diketopyrrolopyrrole layer for hole transportation

Abstract: Diketopyrrole based hole-transport organic semiconductor was employed in perovskite solar cells and charge carrier dynamics was explained.

Cited by 7 publications

References 33 publications

Unusual Hole Transfer Dynamics of the NiO Layer in Methylammonium Lead Tri-iodide Absorber Solar Cells

Unusual Hole Transfer Dynamics of the NiO Layer in Methylammonium Lead Tri-iodide Absorber Solar Cells

Complete Perovskite Solar Cells with Gold Electrodes Studied in the Visible and Near-Infrared Ranges

Bifunctional Interfacial Modification Engineering with Biomimetic Perfluoro-Copolymer-Enabled High-Efficiency and Moisture-Resistant Perovskite Solar Cells

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