Nanofibers (NFs) of poly-3-hexylthiophene (P3HT) assembled in toluene exhibit single-chain J-aggregate character. Absorption, fluorescence emission, and Raman spectroscopy dilute NF dispersions demonstrate that P3HT chains possess long-range intrachain order (planarity) suppresses interchain exciton coupling. We a delicate interplay exists between coupling as revealed through the emission 0–0/0–1 vibronic intensity ratios. Lowering temperature application pressure induces minor perturbations...

Resonance Raman spectroscopic imaging is introduced as a physical probe to identify and spatially map morphology-dependent variations of intra- interchain interactions order in poly-3-hexylthiophene (P3HT) [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) photovoltaic blend thin films. Absorption spectra C=C symmetric stretching modes P3HT/PCBM films show contributions from two distinct species that are assigned aggregated unaggregated P3HT chains with characteristic frequencies...

The effect of the strong electron acceptor, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), on poly(3-hexylthiophene) (P3HT) aggregates is studied. F4-TCNQ commonly used as a dopant for P3HT, however, relatively little currently known about its polymer conformation and packing in presence fullerenes. Resonance Raman optical spectra pristine P3HT or blends with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) doped up to ∼10% w/w show loss pristine-type increasing...

The doping efficiencies of regioregular (r-Re) and regiorandom (r-Ra) poly(3-hexylthiophene) (P3HT) with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) were studied in solution using electron paramagnetic resonance (EPR), (19)F NMR, optical absorption, Raman spectroscopy. EPR spectra doped r-Re P3HT possess significantly larger amounts species than r-Ra similar F4-TCNQ loadings (∼0.1% up to 50%), which is confirmed by corresponding absorption spectra. NMR also show a rapid...

This paper is focused on how the spectroscopic properties of conjugated polymers evolve in size range between single polymer chains and bulk material. The measurements used single-particle spectroscopy techniques include both static dynamic measurements. main observation this work that MEH-PPV rapidly as a function nanoparticle achieve bulk-like for nanoparticles greater than 10 nm size. Nanoparticles were assembled by reprecipitation technique characterized fluorescence emission...

Charge transfer doping efficiencies of π-stacked poly(3-hexylthiophene) (P3HT) aggregate nanofibers are studied using spectroscopic and electron microscopy probes. Solution dispersions self-assembled P3HT doped in the ground electronic state by adding varying amounts (w/w%) strong charge dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ). Careful control self-assembly conditions allows us to select either H- J-aggregate limiting forms, which differ primarily degree purity...

The charge mobility of organic semiconductors are accurately predicted using first principles simulations validated by inelastic neutron scattering experiments.

This study investigates high performance electrochromic windows used on a passive house and residential dwelling to IECC 2021 (i.e., dwelling). In the lab, film switches transmitted solar heat gain coefficient (SHGC) from 0.09 0.7 visible transmittance 0.15 0.82 with power consumption of 1.23 W/m2 during switching times less than 3 minutes. We extrapolate these results window assembly. Building energy models houses were evaluated in Santa Fe, New Mexico. A Monte Carlo analysis for 2020,...

Nanofibers (NFs) of the prototype conjugated polymer, poly(3-hexylthiophene) (P3HT), displaying H- and J-aggregate character are studied using temperature- pressure-dependent photoluminescence (PL) spectroscopy. Single NF spectra show a decrease 0-0/0-1 vibronic intensity ratio from ~2.0 at 300 K to ~1.3 4 K. Temperature-dependent PL line shape parameters (i.e., 0-0 energies ratios) undergo an abrupt change in range ~110-130 suggesting chain packing. Pressure-dependent lifetimes also...

Toward a truly photostable PbSe quantum dot (QD), we apply the thick-shell or "giant" QD structural motif to this notoriously environmentally sensitive nanocrystal system. Namely, using sequential application of two shell-growth techniques-partial-cation exchange and successive ionic layer adsorption reaction (SILAR)-we are able overcoat QDs with sufficiently thick CdSe shells impart new single-QD-level photostability, as evidenced by suppression both photobleaching blinking behavior. We...

Syntheses for a set of new ligands containing one or two carbamoylmethylphosphine oxide (CMPO) fragments appended to pyridine and N-oxide platforms are described. Molecular mechanics analyses gas phase lanthanide-ligand interactions the N-oxides indicate that trifunctional NOPOCO molecules, 2-{[Ph2P(O)][C(O)NEt2]C(H)}C5H4NO (7) 2-{[Ph2P(O)][C(O)NEt2]CHCH2}C5H4NO (8), pentafunctional NOPOP'O'COC'O' 2,6-{[Ph2P(O)][C(O)NEt2]C(H)}2C5H3NO (9) 2,6-{[Ph2P(O)][C(O)NEt2]CHCH2}2C5H3NO (10), should be...

Photoluminescence (PL) of single poly(3-hexylthiophene) (P3HT) J-aggregate nanofibers (NFs) exhibits strong quenching under intensity-modulated pulsed excitation. Initial PL intensities (I0) decay to steady-state levels (ISS) typically within ∼1–10 μs, and large depths (I0/ISS >2) are observed for ∼70% these NFs. Similar studies polymorphic, H-aggregate type P3HT NFs show much smaller ≤1.2). chains in J-type NF π-stacks possess high intrachain order, which has been shown previously promote...

We fabricate poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) thin film solar cells of variable weight/weight (w/w) compositions (i.e., 1:1 to 1:4) systematically perturb polymer packing (aggregation) properties assess their impact on local electronic structure photocurrent generation efficiency. A combination absorption spectroscopy resonance Raman spectroscopic imaging techniques are used quantify spatially map morphology-dependent cofacial, π−π...

Resonance Raman−photocurrent imaging (RRPI) is introduced to spatially map the morphology-dependent polymer aggregation state local photocurrent generation efficiency in poly-(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend thin film photovoltaic devices. The C═C symmetric stretching mode of P3HT decomposed into contributions from aggregated (IC═Cagg, ∼1450 cm−1) unaggregated (IC═Cun, ∼1470 chains, ratios their integrated intensities (IC═Cagg/IC═Cun, R)...

We report a spontaneous and hierarchical self-assembly mechanism of carbon dots prepared from citric acid urea into nanowire structures with large aspect ratios (>50). Scattering-type scanning near-field optical microscopy (s-SNOM) broadly tunable mid-IR excitation was used to interrogate details the process by generating nanoscopic chemical maps local wire morphology composition. s-SNOM images capture evolution formation complex interplay between different constituents directing assembly...

Resonance Raman spectroscopy was used to identify ordered and disordered conformers of poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) blended with the electron acceptor [6,6]-phenyl C61 butyric acid methyl ester (PCBM) in bulk heterojunction (BHJ) solar cells where PCBM intercalates into PBTTT side groups. We show that thiophene ring symmetric C=C stretching mode consists contributions from (ℏωC=C = 1489 cm-1, fwhm ∼ 15 cm-1) 1500 25 components their relative amounts...

Fluorescence emission spectra were recorded for isolated polymer chains of the polyfluorene copolymer, F8BT [poly(9,9-di-n-octylfluorene-alt-benzothiadiazole)], at 298 and 20 K two molecular weights (chain lengths). For long-chain K, observed distribution single-molecule maxima G(Emax) is bimodal, with peaks ∼2.35 eV ("blue") ∼2.25 ("red"). Previously, red forms have been assigned to that possess intrachain contacts, which lowers local singlet exciton energy. At ∼20 collapses into a single...

Resonance Raman spectroscopy reveals conformation and morphology dependent electronic localization in push–pull donor–acceptor co-polymers.

The pathways and dynamics of converting spin-allowed (S = 0) singlet excitons to spin-forbidden 1) triplets have significant implications in determining performance metrics conjugated polymers optoelectronic devices. We study the effect structural ordering factors on triplet formation self-assembled aggregate π-stacked chains poly(3-hexylthiophene) (P3HT) using single-molecule time-resolved intensity modulation electric-field-dependent photoluminescence (PL) spectroscopy. Triplet generation...

We report poly(diphenylamine) thin films with exceptional optical clarity (Tvis ≥ 0.80) and electrochromic solar modulating ability (ΔTsol 0.60). Electropolymerizing diphenylamine in the presence of a polyanionic acid dopant is critical to achieving high macroscale uniformity smoothness, which minimizes scattering maximizes response throughout visible (>400 nm) near-infrared (>700 spectral ranges. then use combinations near- far-field spectroscopies their imaging modes elucidate roles...

Self-assembly of polymers driven by intermolecular and intramolecular interactions leads to rich structural variations in thin films polymer blends. In this work, ordering poly(3-hexylthiophene-2,5-diyl) (P3HT) form nanoparticles (NPs) the self-assembly pattern NPs poly(4-vinylpyridine) (P4VP) matrix are revealed using scattering-type scanning near-field optical microscopy (s-SNOM). The P3HT formed spontaneously when P3HT/P4VP/chloroform solution is spin-cast on unpatterned silicon wafer at...

The luminescence properties of thiocyanate and selenocyanate platinum(II) palladium(II) complexes show strong variations with temperature pressure. d-d band maxima for [Pt(SCN)(4)](PPh(4))(2) (1), [Pt(SCN)(4)](n-Bu(4)N)(2) (2), [Pt(SeCN)(4)](n-Bu(4)N)(2) (4) are centered at ca. 14500 cm(-1) whereas those the [Pd(SCN)(4)](n-Bu(4)N)(2) (3) [Pd(SeCN)(4)](n-Bu(4)N)(2) (5) approximately 2000 lower in energy. Low-temperature spectra from single-crystal samples have broad bands highly resolved...