Data for Dopant-induced Energetic Disorder in Conjugated Polymers: Determinant Roles of Polymer-Dopant Distance and Composite Electronic Structures

The data here is the raw data for Figures in the publication Dopant-Induced Energetic Disorder in Conjugated Polymers: Determinant Roles of Polymer−Dopant Distance and Composite Electronic Structures In the Journal of Physical Chemistry C. (https://doi.org/10.1021/acs.jpcc.3c07197)https://scholarworks.umass.edu/data/1195/thumbnail.jp

Persistent radical anion polymers based on naphthalenediimide and a vinylene spacer

Persistent n-doped conjugated polymers were achieved by doping the electron accepting PDNDIV and PFNDIVpolymers with ionic (TBACN) or neutral (TDAE) dopants. The great electron affinities, as indicated by the low LUMO levels of PDNDIV (−4.09 eV) and PFNDIV (−4.27 eV), facilitated the chemical reduction from either TBACN or TDAE. The low-lying LUMOs of the neutral polymers PDNDIV and PFNDIV were achieved by incorporation of vinylene spacers between the electron poor NDI units to increase the conjugation length without the use of an electron donor, and this was lowered further by an electron-withdrawing fluorinated N-substituent on the NDI moiety. The polymer radical anions were found to persist for several days under ambient conditions by EPR spectroscopy. A distinguishing and noteworthy feature of these polymers is that they can be consecutively reduced by up to four electrons in acetonitrile. Conductivity measurements demonstrate the prospective impact of PDNDIV and PFNDIV for organic electronics

High Energy Density in Azobenzene-based Materials for Photo-Thermal Batteries via Controlled Polymer Architecture and Polymer-Solvent Interactions

Energy densities of ~510 J/g (max: 698 J/g) have been achieved in azobenzene-based syndiotactic-rich poly(methacrylate) polymers. The processing solvent and polymer-solvent interactions are important to achieve morphologically optimal structures for high-energy density materials. This work shows that morphological changes of solid-state syndiotactic polymers, driven by different solvent processings play an important role in controlling the activation energy of Z-E isomerization as well as the shape of the DSC exotherm. Thus, this study shows the crucial role of processing solvents and thin film structure in achieving higher energy densities

Tuning charge transport dynamics via clustering of doping in organic semiconductor thin films

A significant challenge in the rational design of organic thermoelectric materials is to realize simultaneously high electrical conductivity and high induced-voltage in response to a thermal gradient, which is represented by the Seebeck coefficient. Conventional wisdom posits that the polymer alone dictates thermoelectric efficiency. Herein, we show that doping — in particular, clustering of dopants within conjugated polymer films — has a profound and predictable influence on their thermoelectric properties. We correlate Seebeck coefficient and electrical conductivity of iodine-doped poly(3-hexylthiophene) and poly[2,5-bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-3,6-diyl)-alt-(2,2′;5′,2′′;5′′,2′′′-quaterthiophen-5,5′′′-diyl)] films with Kelvin probe force microscopy to highlight the role of the spatial distribution of dopants in determining overall charge transport. We fit the experimental data to a phonon-assisted hopping model and found that the distribution of dopants alters the distribution of the density of states and the Kang–Snyder transport parameter. These results highlight the importance of controlling dopant distribution within conjugated polymer films for thermoelectric and other electronic applications

Enabling an Equitable Energy Transition Through Inclusive Research

Comprehensive and meaningful inclusion of marginalized communities within the research enterprise will be critical to ensuring an equitable, technology-informed, clean energy transition. We provide five key action items for government agencies and philanthropic institutions to operationalize the commitment to an equitable energy transition

White paper: Research Challenges at the Intersection of Energy and Equity in the Energy Transition

Summary report from NSF2026: Conference Workshops to Identify Research Challenges at the Intersection of Energy and Equity in the Energy Transitio

A Hole Transport Bilayer for Efficient and Stable Inverted Perov-skite Solar Cells

We demonstrate that a PTAA/CuI bilayer as a hole transport layer (bilayer HTL) leads to efficient and stable inverted, i.e., p-i-n, perovskite solar cells (PSCs). We observed that devices with a single PTAA interlayer have an average power conversion efficiency (PCE) of 18.1%. In contrast, devices with a bilayer show an enhanced average PCE of 19.4%, with a maximum PCE of 20.34%. The XRD and AFM studies show an improved crystallinity and larger grain size of perovskite films on the CuI surface. Data from ultraviolet photoelectron spectroscopy and impedance spectroscopy suggest that devices with bilayer HTL have increased built-in potential within the device with an enhanced upward band bending at the CuI interface. Compared to devices with a single CuI interlayer, the presence of PTAA in the bilayer-based devices leads to significant suppression of current hysteresis and stable current output at the maximum power point. The bilayer-based devices demonstrate remarkable long-term stability in an inert atmosphere

Revisiting Melting Point Alternation in Hydrocarbons Using PIXEL

We revisit the explanations for the alternation in melting points of linear alkanes by calculating the lattice energies using PIXEL. The lattice energies obtained from PIXEL at optimal box radium are in excellent agreement with the enthalpy of sublimation. Partitioning of the lattice energy indicate that arguments based on the gain in dispersion energy is insufficient to explain the alternation in melting points in linear alkanes. Entropy of fusion plays a major role in the explanation for the observed melting point alternation in alkanes