Extending Long‐lived Charge Separation Between Donor and Acceptor Blocks in Novel Copolymer Architectures Featuring a Sensitizer Core

Schroot, Robert; Schlotthauer, Tina; Dietzek, Benjamin; Jäger, Michael; Schubert, Ulrich S.

doi:10.1002/chem.201704180

Cited by 19 publications

(18 citation statements)

References 38 publications

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“…UV/vis absorption and emission measurement. UV/vis absorption and emission spectra of PPV, Ru1, Ru2, PPV-Ru1 and PPV-Ru2 were measured in CHCl 3 using a Varian-Cary UV-Vis-NIR spectrometer and FLS980 photoluminescence spectrometer (Edinburg Instrument), respectively 71 . Spectroelectrochemical measurements.…”

Section: Methodsmentioning

confidence: 99%

Photocathodes beyond NiO: charge transfer dynamics in a π-conjugated polymer functionalized with Ru photosensitizers

Wahyuono

Seidler

Bold

et al. 2021

Sci Rep

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A conductive polymer (poly(p-phenylenevinylene), PPV) was covalently modified with RuII complexes to develop an all-polymer photocathode as a conceptual alternative to dye-sensitized NiO, which is the current state-of-the-art photocathode in solar fuels research. Photocathodes require efficient light-induced charge-transfer processes and we investigated these processes within our photocathodes using spectroscopic and spectro-electrochemical techniques. Ultrafast hole-injection dynamics in the polymer were investigated by transient absorption spectroscopy and charge transfer at the electrode–electrolyte interface was examined with chopped-light chronoamperometry. Light-induced hole injection from the photosensitizers into the PPV backbone was observed within 10 ps and the resulting charge-separated state (CSS) recombined within ~ 5 ns. This is comparable to CSS lifetimes of conventional NiO-photocathodes. Chopped-light chronoamperometry indicates enhanced charge-transfer at the electrode–electrolyte interface upon sensitization of the PPV with the RuII complexes and p-type behavior of the photocathode. The results presented here show that the polymer backbone behaves like classical molecularly sensitized NiO photocathodes and operates as a hole accepting semiconductor. This in turn demonstrates the feasibility of all-polymer photocathodes for application in solar energy conversion.

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Section: Methodsmentioning

confidence: 99%

Photocathodes beyond NiO: charge transfer dynamics in a π-conjugated polymer functionalized with Ru photosensitizers

Wahyuono

Seidler

Bold

et al. 2021

Sci Rep

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“…Numerous prior studies investigated the distance dependence of electron transfer rates (k ET ) and the role of the intervening medium between the donor and the acceptor. 1 Rigid rod-like donor-bridge-acceptor compounds, [2][3][4][5][6][7][8][9][10][11][12][13] properly folded proteins or DNA equipped with suitable photosensitizers are particularly useful for investigations in which the donor-acceptor distance (r DA ) must be kept constant on the timescale of an electron transfer event. 1,[14][15][16][17] Saturated hydrocarbon bridges or protein backbone typically enable long-range electron transfer via tunneling, 18,19 whereas conjugated bridges or DNA can give rise to hopping.…”

Section: Introductionmentioning

confidence: 99%

Fundamentally Different Distance Dependences of Electron-Transfer Rates for Low and High Driving Forces

Neumann

Wenger

2018

Inorg. Chem.

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The distance dependences of electron transfer rates (k ET) in three homologous series of donor-bridge-acceptor compounds with reaction free energies (G ET 0) of ca.-1.2,-1.6, and-2.0 eV for thermal charge recombination after initial photoinduced charge-separation were studied by transient absorption spectroscopy. In the series with low driving-force, the distance dependence is normal and k ET decreases upon donoracceptor distance (r DA) elongation. In the two series with higher driving-forces, k ET increases with increasing distance over a certain range. This counter-intuitive behavior can be explained by a weakly distance dependent electronic donor-acceptor coupling (H DA) in combination with an increasing reorganization energy (). Our study shows that highly exergonic electron transfers can have distance dependences that differ drastically from those of the more commonly investigated weakly exergonic reactions.

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“…Block copolymers (BCPs) are able to form defined phase-separated structures that are tunable by molecular weight, volume fraction, and intermolecular interactions. , Such complex polymeric architectures are ideal for the precise positioning of functions at the BCP interface to modulate electronic processes. , Conjugated BCPs can somewhat differ in chemical structure and phase behavior due to not only the mostly rigid nature of the conjugated segments but also challenges in chemical synthesis leading to partially ill-defined systems with larger dispersity. − Single reports have demonstrated that classical diblock copolymer morphologies can be achieved also with conjugated D–A BCPs, if the synthetic approach is highly optimized …”

Section: Introductionmentioning

confidence: 99%

Block Junction-Functionalized All-Conjugated Donor–Acceptor Block Copolymers

Nübling

Hopper

Kuei³

et al. 2018

ACS Appl. Mater. Interfaces

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Junction-functionalized donor-acceptor (D-A) block copolymers (BCPs) enable spatial and electronic control over interfacial charge dynamics in excitonic devices such as solar cells. Here we present the design, synthesis, morphology and electronic characterization of block junctionfunctionalized, all-conjugated, all-crystalline D-A BCPs. Poly(3-hexylthiophene) (P3HT), a single thienylated diketopyrrolopyrrole (Th x DPPTh x , x=1 or 2) unit and poly{[N,N'-bis(2octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (PNDIT2) is used as donor, interfacial unit and acceptor, respectively. Almost all C-C coupling steps are accomplished by virtue of C-H activation. Synthesis of the macroreagent H-P3HT-Th x DPPTh x , with x determining its C-H reactivity, is key to the synthesis of various BCPs of type H-P3HT-Th x DPPTh x -block-PNDIT2. Remarkable morphological behavior is determined from a combination of calorimetry, transmission electron microscopy (TEM) and thin film scattering. Block copolymer crystallinity of P3HT and PNDIT2 is reduced indicating frustrated crystallization. A long period l p , is invisible from TEM, but shows up in resonant soft X-ray scattering experiments on a length scale of l p ~60 nm. Charge transfer photoluminescence of H-P3HT-Th x DPPTh x indicates efficient transfer of the excitation energy to the DPP chain end, but is quenched in BCP films. Transient absorption and pump-push-photocurrent spectroscopies reveal geminate recombination (GR) as the main loss channel in as-prepared BCP films independent of junction functionalization. Melt-annealing increases GR as a result of the low degree of crystallinity and poorly defined interfaces, and additionally changes backbone orientation of PNDIT2 from face-on to edge-on. These morphological effects dominate solar cell performance and cause an insensitivity to the presence of the block junction.

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Extending Long‐lived Charge Separation Between Donor and Acceptor Blocks in Novel Copolymer Architectures Featuring a Sensitizer Core

Cited by 19 publications

References 38 publications

Photocathodes beyond NiO: charge transfer dynamics in a π-conjugated polymer functionalized with Ru photosensitizers

Photocathodes beyond NiO: charge transfer dynamics in a π-conjugated polymer functionalized with Ru photosensitizers

Fundamentally Different Distance Dependences of Electron-Transfer Rates for Low and High Driving Forces

Block Junction-Functionalized All-Conjugated Donor–Acceptor Block Copolymers

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