Nonlinear photophysics and charge generation of donor-acceptor two-photon absorbing dyes

2003 ◽  
Author(s):  
Sean M. Kirkpatrick ◽  
Elaine K. Peterman ◽  
Gregg T. Anderson ◽  
Jeffrey E. Franklin ◽  
Jeffery W. Baur
Keyword(s):  
Charge Generation ◽  
Two Photon ◽  
Donor Acceptor

Uphill and downhill charge generation from charge transfer to charge separated states in organic solar cells

2021 ◽  
Author(s):  
Shahidul Alam ◽  
Vojtech Nádaždy ◽  
Tomáš Váry ◽  
Christian Friebe ◽  
Rico Meitzner ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solar Cells ◽  
Charge Transfer ◽  
Energy Level ◽  
Density Of States ◽  
Organic Solar Cells ◽  
Joint Density ◽  
Charge Generation ◽  
Donor Acceptor

Energy level alignments at the organic donor–acceptor interface cannot be predicted from cyclic voltammetry. Onsets for joint density of states and charge generation, reveal cases of energy uphill and – newly observed – downhill charge generation.

scholarly journals Tuning of Hyperpolarizability, One- and Two-Photon Absorption of D-A and D-A-A Type Intramolecular Charge Transfer Based Sensors

2019 ◽  
Author(s):  
Pralok K. Samanta ◽  
Md Mehboob Alam ◽  
Ramprasad Misra ◽  
Swapan K. Pati
Keyword(s):  
Charge Transfer ◽  
Gas Phase ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Photon Absorption ◽  
First Hyperpolarizability ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Nlo Response ◽  
Donor Acceptor

Solvents play an important role in shaping the intramolecular charge transfer (ICT) properties of π-conjugated molecules, which in turn can affect their one-photon absorption (OPA) and two-photon absorption (TPA) as well as the static (hyper)polarizabilities. Here, we study the effect of solvent and donor-acceptor arrangement on linear and nonlinear optical (NLO) response properties of two novel ICT-based fluorescent sensors, one consisting of hemicyanine and dimethylaniline as electron withdrawing and donating groups (molecule 1), respectively and its boron-dipyrromethene (BODIPY, molecule 2)-fused counterpart (molecule 3). Density functional theoretical (DFT) calculations using long-range corrected CAM-B3LYP and M06-2X functionals, suitable for studying properties of ICT molecules, are employed to calculate the desired properties. The dipole moment (µ) as well as the total first hyperpolarizability (β<sub>total</sub>) of the studied molecules in the gas phase is dominantly dictated by the component in the direction of charge transfer. The ratios of vector component of first hyperpolarizability (β<sub>vec</sub>) to β<sub>total</sub> also reveal unidirectional charge transfer process. The properties of the medium significantly affect the OPA, hyperpolarizability and TPA properties of the studied molecules. Time dependent DFT (TDDFT) calculations suggest interchanging between two lowest excited states of molecule 3 from the gas phase to salvation. The direction of charge polarization and dominant transitions among molecular orbitals involved in the OPA and TPA processes are studied. The results presented are expected to be useful in tuning the NLO response of many ICT-based chromophores, especially those with BODIPY acceptors.<br>

scholarly journals Correction: Towards efficient initiators for two-photon induced polymerization: fine tuning of the donor/acceptor properties

2019 ◽  
Vol 4 (2) ◽  
pp. 449-449
Author(s):  
Brigitte Holzer ◽  
Markus Lunzer ◽  
Arnulf Rosspeintner ◽  
Giuseppe Licari ◽  
Maximilian Tromayer ◽  
...  
Keyword(s):  
Fine Tuning ◽  
Two Photon ◽  
Donor Acceptor

Correction for ‘Towards efficient initiators for two-photon induced polymerization: fine tuning of the donor/acceptor properties’ by Brigitte Holzer et al., Mol. Syst. Des. Eng., 2019, DOI: 10.1039/c8me00101d.

Multiple Intramolecular Charge Transfers in Multimodular Donor–Acceptor Chromophores with Large Two-Photon Absorption

2020 ◽  
Vol 124 (45) ◽  
pp. 24631-24643
Author(s):  
Yogajivan Rout ◽  
Alessio Cesaretti ◽  
Elena Ferraguzzi ◽  
Benedetta Carlotti ◽  
Rajneesh Misra
Keyword(s):  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Donor Acceptor

scholarly journals Photoconversion Mechanism at the pn-Homojunction Interface in Single Organic Semiconductor

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1727 ◽  
Author(s):  
Ji-Hyun Lee ◽  
Armand Perrot ◽  
Masahiro Hiramoto ◽  
Seiichiro Izawa
Keyword(s):  
Organic Semiconductors ◽  
Organic Semiconductor ◽  
Energy Structure ◽  
Free Charge ◽  
Charge Generation ◽  
Recombination Processes ◽  
Single Host ◽  
Donor Acceptor ◽  
Doping Technique ◽  
Determining Factor

Clarifying critical differences in free charge generation and recombination processes between inorganic and organic semiconductors is important for developing efficient organic photoconversion devices such as solar cells (SCs) and photodetector. In this study, we analyzed the dependence of doping concentration on the photoconversion process at the organic pn-homojunction interface in a single organic semiconductor using the temperature dependence of J–V characteristics and energy structure measurements. Even though the organic pn-homojunction SC devices were fabricated using a single host material and the doping technique resembling an inorganic pn-homojunction, the charge generation and recombination mechanisms are similar to that of conventional donor/acceptor (D/A) type organic SCs; that is, the charge separation happens from localized exciton and charge transfer (CT) state being separated by the energy offset between adjacent molecules, and the recombination happens from localized charge carrier at two adjacent molecules. The determining factor for photoconversion processes is the localized nature of charges in organic semiconductors. The results demonstrated that controlling the delocalization of the charges is important to realize efficient organic photoconversion devices.

Strategy towards large two-photon absorption cross-sections for diketopyrrolopyrroles

2015 ◽  
Vol 3 (4) ◽  
pp. 742-749 ◽  
Author(s):  
Anna Purc ◽  
Krzysztof Sobczyk ◽  
Yusuke Sakagami ◽  
Akihiro Ando ◽  
Kenji Kamada ◽  
...  
Keyword(s):  
Cross Sections ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Donor Acceptor

Decorating diketopyrrolopyrroles with strongly electron-rich heterocycles led to donor–acceptor–donor architectures possessing two-photon brightness 850–1900 GM.

scholarly journals Long-lived and disorder-free charge transfer states enable endothermic charge separation in efficient non-fullerene organic solar cells

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ture F. Hinrichsen ◽  
Christopher C. S. Chan ◽  
Chao Ma ◽  
David Paleček ◽  
Alexander Gillett ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Organic Solar Cells ◽  
Charge Separation ◽  
Free Charge ◽  
Charge Generation ◽  
Time Resolved ◽  
Thermodynamic Conditions ◽  
Donor Acceptor ◽  
Interfacial Charge

Abstract Organic solar cells based on non-fullerene acceptors can show high charge generation yields despite near-zero donor–acceptor energy offsets to drive charge separation and overcome the mutual Coulomb attraction between electron and hole. Here, we use time-resolved optical spectroscopy to show that free charges in these systems are generated by thermally activated dissociation of interfacial charge-transfer states that occurs over hundreds of picoseconds at room temperature, three orders of magnitude slower than comparable fullerene-based systems. Upon free electron–hole encounters at later times, both charge-transfer states and emissive excitons are regenerated, thus setting up an equilibrium between excitons, charge-transfer states and free charges. Our results suggest that the formation of long-lived and disorder-free charge-transfer states in these systems enables them to operate closely to quasi-thermodynamic conditions with no requirement for energy offsets to drive interfacial charge separation and achieve suppressed non-radiative recombination.

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