Related papers: Highly-Efficient Charge Separation and Polaron Del…
Earlier reports demonstrated that ternary organic solar cells (OSC) made of donor polymers (D) blended with different mixtures of fullerene acceptors (A:A) performed very similarly. This finding is surprising, as the corresponding fullerene…
The separation of photogenerated polaron pairs in organic bulk heterojunction solar cells is the intermediate but crucial step between exciton dissociation and charge transport to the electrodes. In state-of-the-art devices, above 80% of…
We investigated photogeneration yield and recombination dynamics in blends of poly(3-hexyl thiophene) (P3HT) and poly[2-methoxy-5-(30,70-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) with [6,6]- phenyl-C61 butyric acid methyl ester…
We studied the recombination dynamics of charge carriers in organic bulk heterojunction solar cells made of the blend system poly(2,5-bis(3-dodecyl thiophen-2-yl) thieno[2,3-b]thiophene) (pBTCT-C12):[6,6]-phenyl-C61-butyric acid methyl…
Charged polarons in thin films of polymer-fullerene composites are investigated by light-induced electron paramagnetic resonance (EPR) at 9.5 GHz (X-band) and 130 GHz (D-band). The materials studied were poly(3-hexylthiophene) (PHT),…
The unique properties of organic semiconductors make them versatile base materials for many applications ranging from light emitting diodes to transistors. The low spin-orbit coupling typical for carbon-based materials and the resulting…
Inclusion of heavy metal atoms in a polymer backbone allows transitions between the singlet and triplet manifolds. Interfacial dissociation of triplet excitons constitutes a viable mechanism for enhancing photovoltaic (PV) efficiencies in…
The mechanism of electron-hole separation in organic solar cells is currently hotly debated. Recent experimental work suggests that these charges can separate on extremely short timescales (<100 fs). This can be understood in terms of…
We investigated the photocurrent in poly(3-hexylthiophene-2,5-diyl) (P3HT):[6,6]-phenyl-C$_{61}$ butyric acid methyl ester (PCBM) solar cells by applying a pulsed measurement technique. For annealed samples, a point of optimal symmetry…
In organic solar cells, photogenerated singlet excitons form charge transfer (CT) complexes, which subsequently split into free charge carriers. Here, we consider the contributions of excess energy and molecular quadrupole moments to the…
We report transient electron paramagnetic resonance (trEPR) measurements with sub-microsecond time resolution performed on a P3HT:PCBM blend at low temperature. The trEPR spectrum immediately following photoexcitation reveals signatures of…
Resonance Raman experiments on doped and photoexcited single crystals of mixed-halide $MX$ complexes ($M$=Pt; $X$=Cl,Br) clearly indicate charge separation: electron polarons preferentially locate on PtBr segments while hole polarons are…
In polymer:fullerene solar cells, the origin of the losses in the field-dependent photocurrent is still controversially debated. We contribute to the ongoing discussion by performing photo-induced charge extraction measurements on…
In polymeric semiconductors, charge carriers are polarons, which means that the excess charge deforms the molecular structure of the polymer chain that hosts it. This effect results in distinctive signatures in the vibrational modes of the…
Charge carrier recombination is studied in operational organic solar cells made from the polymer:fullerene system PCDTBT:PC71BM (poly[N-9"-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] :…
The major loss mechanism of photogenerated polarons was investigated in P3HT:PCBM solar cells by the photo-CELIV technique. For pristine and annealed devices, we find that the experimental data can be explained by a bimolecular…
Organic solar cells must separate strongly bound electron-hole pairs into free charges. This is achieved at interfaces between electron donor and acceptor organic semiconductors. The most popular electron acceptor is the fullerene…
Hybrid conjugated polymer/fullerene filaments based on MEH-PPV/PVP/PCBM are prepared by electrospinning, and their properties assessed by scanning electron, atomic and lateral force, tunnelling, and confocal microscopy, as well as by…
All-organic-based photovoltaic solar cells have attracted considerable attention because of their low-cost processing and short energy payback time. In such systems the primary dissociation of an optical excitation into a pair of…
All-polymer solar cells gained substantial achievements in recent years, offering numerous unsettled subjects for mechanical researchers. Based on the Su-Schrieffer-Heeger model, we then simulate the ultrafast dynamics of charge-transfer…