Azatriphenylene-based D-A-D-typed hole-transporting materials for perovskite solar cells with tunable energy levels and high mobility

Sun, Zhu-Zhu; Feng, Shuai; Ding, Wei‐Lu; Peng, Xing‐Liang; Liu, Jinglun; Xu, Xing-Lei

doi:10.1016/j.solener.2021.06.030

Cited by 29 publications

(19 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As previously reported, , the Stokes shift (Δλ st ) can be calculated by the formula of Δλ st = λ em - λ abs , where λ em and λ abs denote the maximum emission and absorption wavelengths, respectively. As shown in Table , the Stokes shifts of tailored HTMs are 69 (FDT), 95 (SM28), 77 (SM29), and 95 (SM30) nm.…”

Section: Resultsmentioning

confidence: 99%

Structural Engineering of FDT toward Promising Spiro-Typed Hole-Transporting Materials: Promoting the Hole Transport and Stabilizing the HOMO Levels

et al. 2022

Self Cite

View full text Add to dashboard Cite

Design of a new spiro-typed core structure is one of the most important approaches for developing highly efficient hole-transporting materials (HTMs). In this work, the strategies of modifying with O/S heteroatoms and introducing a helical π-linker are evaluated based on the typical FDT molecule. Theoretical calculations show that all the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) of the studied HTMs are matched well with the energy band structure of perovskite, and the HOMO levels display a gradually negative-shifted trend from the FDT to SM30, which means that the favorable hole extraction and the easy interfacial energy regulation can be anticipated. Compared to the light absorption of the FDT, the absorption spectra of new tailored HTMs are slightly red-shifted. More importantly, our results indicate that introducing a helical π-linker and modification with heteroatoms in the spiro-typed core can be the effective methods to promote the hole transport ability of HTMs. Both the methods can effectually heighten the crystal stacking and intermolecular electronic couplings and further facilitate the hole transport of HTMs. Furthermore, the large Stokes shifts and the better solubility are also displayed for the newly tailored HTMs. In sum, this work provides useful insights for the design of highly efficient HTMs, and three new spiro-typed HTMs are proposed.

show abstract

Section: Resultsmentioning

confidence: 99%

Structural Engineering of FDT toward Promising Spiro-Typed Hole-Transporting Materials: Promoting the Hole Transport and Stabilizing the HOMO Levels

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…In addition, the exciton binding energy ( E b ) is also an essential factor in describing the charge separation efficiency of the HTMs. , To achieve high carrier transport, the bound electron–hole pairs should be dissociated into wholly separated positive and negative charges to escape from the Coulombic interaction . The E b is the energy difference between the neutral exciton and the two free charge carriers, which can be described as , E normalb = E normalH − normalL − E normalS 1 where E H–L is the energy difference between the HOMO and the LUMO and E S1 is the first singlet excitation energy.…”

Section: Resultsmentioning

confidence: 99%

Molecular Electronic Study of Spiro-[cyclopenta[1,2-b:5,4-b′]dithiophene-4,9′-fluorene] Derivatives: Route to Decent Hole-Transporting Materials

Zhang

Orlandi

et al. 2022

J. Phys. Chem. C

View full text Add to dashboard Cite

Spiro-type molecules have been extensively explored as hole-transporting materials (HTMs) in perovskite solar cells (PSCs). However, a closer look at the rule of design of such molecules is missing, and a combined experimental and theoretical study is needed. In this work, three spiro-[cyclopenta [1,2-b:5,4-b′]dithiophene-4,9′-fluorene] (SDTF) derivatives decorated with triphenylamine have been designed and synthesized. The thermal and optoelectronic properties, single-crystal structures, and chargetransport properties have been extensively investigated to reveal the impact of the linkage position of triphenylamine groups by combining experimental and theoretical methods, and the results are consistent with each other. Moreover, transfer integrals and reorganization energies in these molecules are also calculated to predict hole mobility. Our comprehensive studies show that SDTF-2 with a suitable energy alignment, good hole injection/ transportability, and high theoretical hole mobility can be employed for efficient perovskite solar cells, achieving a high power conversion efficiency of 19.3%. In addition, first-principle calculations reveal that the strong interactions between SDTF-2 and the perovskite surface can facilitate fast hole extraction. Our way of study has provided useful information as part of the Materials Genome Initiative. We hope our investigation will offer a reliable path to predict or find the potential of novel spiro-type HTMs to become the alternative choice of spiro-OMeTAD.

show abstract

“…In order to more accurately calculate the detailed information under this configuration, quantum chemistry is usually used in the face-to-face electron transport model (FMOs illustrated in Figure S6) because the electronic coupling is dominant in this configuration. When only one-dimensional channel transmission is considered, the diffusion coefficient will be simplified, and the calculation formula of electron mobility is followed as , μ normale = e r 2 2 K normalB T k normale …”

Section: Resultsmentioning

confidence: 99%

“…k e is calculated by the Marcus equation, and for self-exchange reactions, the rate is affected by the reorganization energy and the charge transfer integral. , λ can be split into two contributions, estimated from four energy values. In this work, the transfer integral V e was determined by the direct coupling, , which treated the states from the quantum calculation as charge-localizing unrestricted Hartree–Fock configurations to mimic the initial and final states.…”

Section: Resultsmentioning

confidence: 99%

Nonfused Dimethoxybenzene Electron Acceptors in Organic Solar Cells: From Molecular Design to Structure–Performance Relationship

Zang

Song

et al. 2022

J. Phys. Chem. C

View full text Add to dashboard Cite

The photovoltaic mechanism of asymmetric nonfullerene acceptors (NFAs) has not been sufficiently understood, although it is developing as a forceful method to design effective organic solar cells. This article systematically investigated and designed several configurations of nonfused acceptors at the micro level. Skeletons were constructed by a central 1,4-dimethoxybenzene core and flanked by different dithieno-pyrroles and thiophene derivates as electron-donating groups; the end-capped groups were composed of two 1,1-dicyanomethyl-3-indanone. Through theoretical calculation, one found that the designed DBPT series possessed narrower gaps, broadened the absorption to the near-infrared region, larger electron-accepting power, and separated the distance of holes and electrons. They also yielded enhancement mobility, which may relate to the significant dipole moment and electronic coupling. Furthermore, we constructed the device models by using PBDB-T as the donor. The heterojunction model results show that the optimized blends of PBDB-T/DBPT-4F achieved more intermolecular fragment charge amounts, more CT states, and smaller binding energy, showing a significant charge separation/recombination ratio. Then, under the macro-scale model, the device PBDB-T/DBPT-4F has a better power conversion efficiency of 14.69%, owing to a large simulated J SC of 18.82 mA cm −2 , consistent with the trend of better interfacial transfer property. This work provided the global description of the molecular light response and the microscopic physicochemical mechanism of the intermolecular charge transfer process, which also sheds light on the structure− property relationship of unfused asymmetric NFAs and enables the strategy to develop valuable OSCs.

show abstract

Azatriphenylene-based D-A-D-typed hole-transporting materials for perovskite solar cells with tunable energy levels and high mobility

Cited by 29 publications

References 49 publications

Structural Engineering of FDT toward Promising Spiro-Typed Hole-Transporting Materials: Promoting the Hole Transport and Stabilizing the HOMO Levels

Structural Engineering of FDT toward Promising Spiro-Typed Hole-Transporting Materials: Promoting the Hole Transport and Stabilizing the HOMO Levels

Molecular Electronic Study of Spiro-[cyclopenta[1,2-b:5,4-b′]dithiophene-4,9′-fluorene] Derivatives: Route to Decent Hole-Transporting Materials

Nonfused Dimethoxybenzene Electron Acceptors in Organic Solar Cells: From Molecular Design to Structure–Performance Relationship

Contact Info

Product

Resources

About