Ullazine Donor–π bridge‐Acceptor Organic Dyes for Dye‐Sensitized Solar Cells

Zhang, Yanbing; Cheema, Hammad; McNamara, Louis E.; Hunt, Leigh Anna; Hammer, Nathan I.; Delcamp, Jared H.

doi:10.1002/chem.201800030

Cited by 19 publications

(28 citation statements)

References 36 publications

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“…Consequently, several tailored-made Ullazines have been developed to be employed as photosensitizers in dye-sensitized solar cells. [5][6][7][8][9] Despite their potential, Ullazines have been barely considered as organic components of perovskite solar cells (PSCs), with the exception of compound 1 (Figure 1) reported in 2017. [10] A PSC device fabricated using 1 as a small molecule hole-transporting material (HTM) attained a power conversion efficiency (PCE) of 13.08%.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Engineering of Thienyl Functionalized Ullazines as Hole‐Transporting Materials for Perovskite Solar Cells

et al. 2021

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Organic hole‐transporting materials (HTMs) based on the Ullazine core yield so far only moderate power conversion efficiencies of up to 13.08% in perovskite solar cells (PSCs). Aiming to fabricate efficient and stable PSCs, novel Ullazine derivatives bearing thiophene units were designed and synthesized, allowing modulation of the electronic states of the HTMs and further providing defect passivation of the perovskite surface. Experimental and theoretical analysis show that thiophene units with ‐N(p‐MeOC6H4)2 groups improve the conductivity of Ullazine HTMs, boosting the efficiency of PSCs to 20.21%. This value is the highest reported to date for Ullazine‐based HTMs, and is close to the performance of Spiro‐OMeTAD. In addition, unencapsulated PSCs based on the champion Ullazine exhibit superior stability with respect to Spiro‐OMeTAD, retaining nearly 90% of the initial efficiency following 1000 h aging, which is ascribed to a combination of higher water repellency and passivation of defects on the perovskite surface. This work demonstrates the high potential of HTMs based on Ullazine core as substitutes to Spiro‐OMeTAD.

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Section: Introductionmentioning

confidence: 99%

“…Consequently, several tailored‐made Ullazines have been developed to be employed as photosensitizers in dye‐sensitized solar cells. [ 5–9 ]…”

Section: Introductionmentioning

confidence: 99%

Molecular Engineering of Thienyl Functionalized Ullazines as Hole‐Transporting Materials for Perovskite Solar Cells

et al. 2021

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“…The excited state would ideally have a long lifetime to effectively drive subsequent processes such as energy/electron transfer that initiate chemistry or photocurrent. Although there have been various approaches to attaining molecular panchromatic absorbers, − no clear design criteria have emerged to attain superchromophores that simultaneously afford panchromatic absorption and favorable excited-state properties.…”

Section: Introductionmentioning

confidence: 99%

Origin of Panchromaticity in Multichromophore–Tetrapyrrole Arrays

et al. 2018

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Panchromatic absorbers that have robust photophysical properties enable new designs for molecular-based light-harvesting systems. Herein, we report experimental and theoretical studies of the spectral, redox, and excited-state properties of a series of perylene-monoimide-ethyne-porphyrin arrays wherein the number of perylene-monoimide units is stepped from one to four. In the arrays, a profound shift of absorption intensity from the strong violet-blue (B and B) bands of typical porphyrins into the green, red, and near-infrared (Q and Q) regions stems from mixing of chromophore and tetrapyrrole molecular orbitals (MOs), which gives multiplets of MOs having electron density spread over the entire array. This reduces the extensive mixing between porphyrin excited-state configurations and the transition-dipole addition and subtraction that normally leads to intense B and weak Q bands. Reduced configurational mixing derives from moderate effects of the ethyne and perylene on the MO energies and a more substantial effect of electron-density delocalization to reduce the configuration-interaction energy. Quantitative oscillator-strength analysis shows that porphyrin intensity is also shifted into the perylene-like green-region absorption and that the ethyne linkers lend absorption intensity. The reduced porphyrin configurational mixing also endows the S state with bacteriochlorin-like properties, including a 1-5 ns lifetime.

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“…The HF donor has shown exceptional surface insulation of electrons injected into a metal oxide semiconductor such as TiO 2 from oxidants in the electrolyte solution, which reduces the detrimental electron transfer process referred to as recombination. The extended charge separation lifetimes seen when using the HF donor is essential when using metal‐based materials such as Co 3+ and Cu 2+ in the electrolyte since they can undergo fast electron transfers when close to the TiO 2 surface . The HF donor's ability to provide surface protection has led to its successful incorporation in a large number of DSC dyes, including dyes found in four of the five best‐performing DSC devices (Figure ) …”

Section: Figurementioning

confidence: 99%

Robust, Scalable Synthesis of the Bulky Hagfeldt Donor for Dye‐Sensitized Solar Cells

2019

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The bulky triarylamine group commonly referred to as the "Hagfeldtd onor" is ak ey buildingb lock found in many of the organic dyes used in dye-sensitized applications such as dyesensitized solar cells (DSCs). This building block has gained popularity owing to its presence in many of the best-performing DSC devicesr eported to date, which use dyes containing this donorg roup. The Hagfeldt donor provides ad esirable 3dimensionals tructure that aids in surface protection of electrons injected into the semiconductor from oxidants in the electrolyte, allowing for record-setting cobalt-and copperbased redoxs huttles to be utilized more frequently.H owever, the synthesiso ft his molecule has provenu nreliable form any routes. This study concerns an ovel, reliable and scalable fivestep synthesis of the Hagfeldt donor.Supporting Information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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Ullazine Donor–π bridge‐Acceptor Organic Dyes for Dye‐Sensitized Solar Cells

Cited by 19 publications

References 36 publications

Molecular Engineering of Thienyl Functionalized Ullazines as Hole‐Transporting Materials for Perovskite Solar Cells

Molecular Engineering of Thienyl Functionalized Ullazines as Hole‐Transporting Materials for Perovskite Solar Cells

Origin of Panchromaticity in Multichromophore–Tetrapyrrole Arrays

Robust, Scalable Synthesis of the Bulky Hagfeldt Donor for Dye‐Sensitized Solar Cells

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