Narrow bandgap (1.37–1.46 eV) polymers incorporating a head-to-head linkage containing 3-alkoxy-3′-alkyl-2,2′-bithiophene are synthesized. The head-to-head linkage enables polymers with sufficient solubility and the noncovalent sulfur–oxygen interaction affords polymers with high degree of backbone planarity and film ordering. When integrated into polymer solar cells, the polymers show a promising power conversion efficiency approaching 10%.
The Weekly Reader Picks are a new series designed to introduce The Old Reader users to some of the great feeds that we enjoy.
While it’s not always easy to recommend music to people, there are many great feeds that cover a large range of musical tastes and genres. Without further ado, here are our current recommendations for music related feeds.
American Songwriter offers album reviews, artist interviews, recording technology reviews and much more. A core group of regular (but not overly frequent posters) will get you up to speed on great new music from all genres.
NPR Music offers a ton of great music related content. Our favorite is their tiny desk concerts feed, featuring anything from pop to jazz and world music. Artists play live standing behind a desk in the NPR office, usually playing into a single microphone. It’s a great way to see and hear new artists in their purest form.
If you really want to get stay informed on new music, check out the Stereogum feed, which probes every nook and cranny of popular music.
Song Exploder is one of our new favorites. Each episode features a different artist and uncovers the stories behind how one of their songs was written and recorded. It’s inspirational, and the diversity of the guests pretty much guarantees there will be something for everybody.
The Needle Drop’s Anthony Fantano has been turning people on to new music since 2007. The self-proclaimed “Internet’s Busiest Music Nerd” continually posts reviews the best and worst pop, rock, and hip hop.
We hope some of these will make interesting and new additions to your feeds.
The chemical structure of conjugated polymers plays an important role in determining their physical properties that, in turn, dictates their performance in photovoltaic devices. 5-Fluoro-2,1,3-benzothiadiazole, an asymmetric unit, is incorporated into a thiophene-based polymer backbone to generate a hole conducting polymers with controlled regioregularity. A high dipole moment is seen in regioregular polymers, which have a tighter interchain stacking that promotes the formation of a morphology in bulk heterojunction blends with improved power conversion efficiencies. Aliphatic side chain substitution is systematically varied to understand the influence of side chain length and symmetry on the morphology and resultant performance. This side chain modification is found to influence crystal orientation and the phase separated morphology. Using the asymmetric side chain substitution with regioregularity of the main chain, an optimized power conversion efficiency of 9.06% is achieved, with an open circuit voltage of 0.72 V, a short circuit current of 19.63 mA cm−2, and a fill factor over 65%. These results demonstrate that the local chemical environment can dramatically influence the physical properties of the resultant material.
The unidirectional regioregular conjugated polymers using 5-fluoro-2,1,3-benzothiadiazole (FBT) asymmetric unit were synthesized. Compared with the regiorandom control polymers, the regioregular polymers with a unidirectional fluorine atom alignment can lead to a progressive dipole moment along the backbone. The regioregular FBT polymers exhibit tighter interchain stacking and better morphology in bulk heterojunction blends, giving rise to improved power conversion efficiency.
When I was teenager, my stay-at-home mom started her photography career. I remember assisting her on a shoot. Our backyard was filled with baby cousins waddling in every direction, and she had rented a cherry picker (!) to try to capture the scene from above.… Read more
Calyx is a famous, heroic, radical ISP that has been involved in groundbreaking litigation -- they were the first company to ever get a secret Patriot Act warrant unsealed, fighting for 11 years to overturn the gag order. (more…)