We report herein a comparison of the photophysics series polythiophenes with ionization potentials ranging from 4.8 to 5.6 eV as pristine films and when blended 5 wt % 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]C61 (PCBM). Three polymers are observed give amorphous films, attributed nonplanar geometry their backbone while other five polymers, including poly(3-hexylthiophene), more crystalline films. Optical excitation is by transient absorption spectroscopy rise polymer triplet formation. For...

The charge generation and recombination dynamics in blend films of a poly(3-hexylthiophene) (P3HT) methanofullerene derivative (PCBM) were comprehensively studied by transient absorption spectroscopy the wavelength region from 450 to 1650 nm under various excitation intensities different wavelengths. In homogeneously mixed regiorandom P3HT (RRa-P3HT) PCBM, virtually all excitons can reach interface RRa-P3HT/PCBM then form bound radical pairs. However, two-thirds them geminately recombine...

The formation dynamics of polaron pairs, polarons, and triplet excitons in regiorandom regioregular poly(3-hexylthiophene) (RRa-P3HT RR-P3HT) films was comprehensively studied by transient absorption spectroscopy over the wide wavelength region from 500 to 1650 nm under various excitation intensities. In both RRa-P3HT RR-P3HT films, pairs were generated not relaxed singlet exciton states but hot on a time scale <100 fs decayed monomolecularly geminate recombination. rapidly picosecond higher...

Abstract A crucial issue facing polymer-based solar cells is how to manage the energetics of polymer/fullerene blends maximize short-circuit current density and open-circuit voltage at same time thus power conversion efficiency. Here we demonstrate that use a naphthobisoxadiazole-based polymer with narrow bandgap 1.52 eV leads high voltages approximately 1 V high-power efficiencies ∼9% in cells, resulting photon energy loss as small ∼0.5 eV, which much smaller than typical systems (0.7–1.0...

The development of semiconducting polymers is imperative to improve the performance polymer-based solar cells (PSCs). In this study, new based on naphtho[1,2-c:5,6-c′]bis[1,2,5]thiadiazole (NTz), PNTz4TF2 and PNTz4TF4, having 3,3′-difluoro-2,2′-bithiophene 3,3′,4,4′-tetrafluoro-2,2′-bithiophene, respectively, are designed synthesized. These possess a deeper HOMO energy level than their counterpart, PNTz4T, which results in higher open-circuit voltages cells. This concequently reduces photon...

Perovskite solar cells exhibit improved photovoltaic parameters with increasing perovskite grain size. The larger photocurrent is due to the enhanced absorption efficiency for thicker layers. open-circuit voltage (VOC) ascribed reduced trap-assisted recombination grains. As a result, power conversion exceeds 19% at best. Further improvement in VOC would be possible if trap density were reduced. service our authors and readers, this journal provides supporting information supplied by authors....

Singlet exciton diffusion plays a central role in the photovoltaic conversion organic photovoltaics (OPVs). Upon light absorption, singlet excitons are promptly generated materials instead of charge carriers because dielectric constant (εr) is small (∼3–4), which sharp contrast to inorganic and perovskite solar cells. In order convert carriers, need diffuse into an interface between electron donor acceptor before deactivating ground state. Therefore, fundamental understanding dynamics one...

A polymer/polymer blend solar cell with an external quantum efficiency approaching 60% and the best power conversion of 5.73% is fabricated. The efficient charge-carrier generation collection, comparable to those polymer/fullerene cells, are found be main reasons for superior device performance.

In this review, we provide an overview of recent progress towards the performance enhancement polymer/polymer blend solar cells.

Abstract The toxicity of lead perovskite hampers the commercialization perovskite-based photovoltaics. While tin is a promising alternative, facile oxidation tin(II) to tin(IV) causes high density defects, resulting in lower solar cell efficiencies. Here, we show that tin(0) nanoparticles precursor solution can scavenge impurities, and demonstrate this treatment leads effectively tin(IV)-free films with strong photoluminescence prolonged decay lifetimes. These are generated by selective...

We examined the mechanisms underlying free carrier generation in a very topical PM6/Y6 organic solar cell. observed slow yet efficient spatial charge dissociation driven by downhill energy relaxation through interfacial cascade.

Enhancement of the light-harvesting efficiency in poly(3-hexylthiophene)/fullerene derivative (P3HT/PCBM) bulk heterojunction solar cells has been demonstrated by introduction near-infrared phthalocyanine molecules as third component at P3HT/PCBM interface. The silicon (SiPc) increased short-circuit current density and hence improved overall power conversion 20%, compared to control device. For P3HT/PCBM/SiPc devices, two distinct external quantum (EQE) peaks were observed wavelengths for...

Abstract Selective dye loading at the polymer/fullerene interface was studied for ternary blend bulk heterojunction solar cells, consisting of regioregular poly(3‐hexylthiophene) (RR‐P3HT), a fullerene derivative (PCBM), and silicon phthalocyanine (SiPc) as light‐harvesting dye. The photocurrent density power conversion efficiency cells were most improved by SiPc with content 4.8 wt%. absorption surface energy measurements suggested that is located in disordered P3HT domains RR‐P3HT/PCBM...

Low-bandgap donor/acceptor polymer blend solar cells are fabricated. The device performance is optimized at a donor:acceptor blending ratio of 70:30 wt% to result in short-circuit current density 8.85 mA cm−2, fill factor 0.55, and an open circuit voltage 0.84 V. high PCE , which exceeds 4%, demonstrates the potential polymer/polymer as alternative polymer/fullerene cells.

Ternary blend all-polymer solar cells open a new avenue for accelerating improvement in the efficiency of non-fullerene thin-film organic photovoltaics.

Multi-colored dye-sensitized polymer/fullerene solar cells with two different near-IR dyes, silicon phthalocyanine bis(trihexylsilyl oxide) (SiPc) and naphthalocyanine (SiNc), enhanced power conversion efficiency up to 4.3%, compared that of the individual ternary blend a single dye under AM1.5G illumination.

The highest power conversion efficiency (PCE) of 2.7% has been achieved for all-polymer solar cells made with a blend poly(3-hexylthiophene) (P3HT, electron donor) and poly[2,7-(9,9-didodecylfluorene)-alt-5,5-(4',7'-bis(2-thienyl)-2',1',3'-benzothiadiazole)] (PF12TBT, acceptor). PCE the P3HT/PF12TBT increases from 1.9% to an increase in molecular weight (Mw) PF12TBT 8500 78 000 g mol(-1). In device high-molecular-weight PF12TBT, efficient charge generation is maintained even at high...

Polymer-based solar cells have made great progress during the past decade and consequently are now attracting extensive academic commercial interest because of their potential advantages: lightweight, flexible, low cost, high-throughput production. On other hand, recent in analytical tools has profoundly enhanced our understanding underlying mechanism polymer-based cells, which can provide valuable guidelines for materials design device engineering therefore is essential further improvement...

The bimolecular recombination dynamics in blend films of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) has been studied by transient absorption spectroscopy. On a microsecond time scale, two polaron bands were observed at 700 1000 nm exhibited different dynamics. 700-nm band decayed with time-independent rate 10(-12) cm(3) s(-1). activation energy was as small approximately 0.078 eV independently the carrier density. other hand, 1000-nm time-dependent...

The light-harvesting mechanism in polymer:fullerene:dye ternary blends was comprehensively studied by transient absorption spectroscopy. blend films consist of poly(3-hexylthiophene) (P3HT), a fullerene derivative (PCBM), and silicon phthalocyanine (SiPc) as dye. Upon dye excitation P3HT:PCBM:SiPc blends, P3HT polarons SiPc anions were generated from excitons, then electrons shifted to PCBM, suggesting that molecules are selectively located disordered matrix mixed with PCBM at the P3HT/PCBM...

Singlet exciton dynamics in crystalline domains of regioregular poly(3-hexylthiophene) (P3HT) films was studied by transient absorption spectroscopy. Upon the selective excitation P3HT at edge, no red shift singlet band observed with an elapse time, suggesting relatively homogeneous without downhill relaxation energetic disorder. Even under such conditions, annihilation rate coefficient γ(t) still dependent on ∝ t(-1/2), which is attributed to anisotropic diffusion domains. From coefficient,...

Initial improvement in power conversion efficiency (PCE) during ambient storage is often seen perovskite solar cells (PSCs). In this work, we studied the origin of PCE enhancement by on typical n-i-p PSCs. We found improvements both fill factor and open-circuit voltage first 2 days storage. By analyzing temperature light intensity-dependent VOC, that charge recombination mechanism changed from surface- to bulk-dominated because defect passivation at surface upon addition, improves...

The effects of thermal annealing before and after Al deposition on poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C61 butyric acid methyl ester (PCBM) blend solar cells were investigated by current density-voltage measurements x-ray photoelectron spectroscopy (XPS). Compared to the preannealed device, postannealed device exhibited enhanced open-circuit voltage (VOC), which is ascribed decrease in reverse saturation density J0. XPS demonstrated that P3HT dominant at interface while PCBM instead...