Solution‐processed organic photovoltaics (OPVs) have continued to show their potential as a low‐cost power generation technology; however, there has been a significant gap between device efficiencies fabricated with lab‐scale techniques—i.e., spin coating—and scalable deposition methods. Herein, temperature‐controlled slot die deposition is developed for the photoactive layer of OPVs. The influence of solution and substrate temperatures on photoactive films and their effects on power conversion efficiency (PCE) in slot die coated OPVs using a 3D printer‐based slot die coater are studied on the basis of device performance, molecular structure, film morphology, and carrier transport behavior. These studies clearly demonstrate that both substrate and solution temperatures during slot die coating can influence device performance, and the combination of hot substrate (120 °C) and hot solution (90 °C) conditions result in mechanically robust films with PCE values up to 10.0% using this scalable deposition method in air. The efficiency is close to that of state‐of‐the‐art devices fabricated by spin coating. The deposition condition is translated to roll‐to‐roll processing without further modification and results in flexible OPVs with PCE values above 7%. The results underscore the promising potential of temperature‐controlled slot die coating for roll‐to‐roll manufacturing of high performance OPVs.

A regioregular D1-A-D2-A terpolymer PDTST­TBDT incorporating dithieno­[3,2-b:2′,3′-d]­silole (DTS, D1) and benzo­[1,2-b:4,5-b]­dithiophene (BDT, D2) units with perfectly controlled thieno­[3,4-b]­thiophene (TT, A) orientation was synthesized for the first time. The thermal, optical, and electrochemical properties of the regioregular PDTSTTBDT were characterized and compared with the random PDTSTTBDT without structural regioregularity. The regioregular PDTSTTBDT showed ideal optical bandgap (1.45 eV), lower lying HOMO energy level, and higher degree of crystallinity compared to the random PDTST­TBDT. Moreover, it exhibited excellent solubility in nonhalogenated solvents as well as halogenated solvents. The inverted bulk-heterojunction polymer solar cells (PSCs) based on the regioregular PDTST­TBDT and o-xylene process solvent showed a power conversion efficiency as high as 6.14%, which is 500% higher than the random PDTST­TBDT-based PSCs. It was found that the remarkable enhancement of photovoltaic performance in regioregular PDTST­TBDT-based PSCs is mainly due to improved light absorption, effective polymer ordering, and high charge carrier mobility.

High-performance transparent pressure sensors have been successfully fabricated using sea-urchin shaped metal nanoparticles and polyurethane microdome arrays for real-time monitoring.

We synthesized and characterized two kinds of regioregular polymers that were based on thieno [3,4-b]thiophene as an electron-accepting unit and benzo [1,2-b:4,5-b′]dithiophene as the electron-donating unit with different side chain, alkylthio and alkyl thiophenes, named rr-PTBS and rr-PTB7-Th, respectively. Because of the partial introduction of the alkylthio thiophene side chain, rr-PTBS showed red-shifted absorption and a deeper HOMO level compared to those of rr-PTB7-Th. In addition, both rr-PTBS:PC 71 BM and rr-PTB7-Th:PC 71 BM blended films showed face-on orientations stronger than those of regiorandom PTB7-Th. However, the rr-PTB7-Th:PC 71 BM blended film showed a peak in the outof-plane direction much weaker than those of rr-PTBS:PC 71 BM and PTB7-Th:PC 71 BM blended films. Moreover, the rr-PTBS:PC 71 BM blended film exhibited charge carrier mobility (μ e /μ h ∼ 1.01) much more balanced than that of the rr-PTB7-Th:PC 71 BM blended film (μ e /μ h ∼ 1.23). The bulkheterojunction organic photovoltaic (OPV) device based on rr-PTBS and the 1,8-diiodooctane additive showed a high power conversion efficiency (PCE) of 8.68%, while the OPV device based on rr-PTB7-Th and the 1,8-diiodooctane additive showed a PCE of 7.04%. Finally, an OPV device using rr-PTBS, the diphenyl ether additive, and Micro Lens Film exhibited a short-circuit current (J sc ) of 19.72 mA/cm 2 , an open-circuit voltage (V oc ) of 0.82 V, and a fill factor (FF) of 63.82%, thus resulting in a PCE of 10.31%.

In this Article, low-bandgap pTTDPP-BT polymers based on electron-accepting pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) and benzothiadiazole (BT) and electron-donating thienothiophene (TT) moieties were synthesized. Phototransistors have been fabricated using ambipolar-behaving pTTDPP-BT polymers as active channel materials. The electrical and photoresponsive properties of the pTTDPP-BT phototransistors were strongly dependent on the film annealing temperature. As-spun pTTDPP-BT phototransistors exhibited a low hole mobility of 0.007 cm/(V·s) and a low electron mobility of 0.005 cm/(V·s), which resulted in low photocurrent detection due to the limited transport of the charge carriers. Thermal treatment of the polymer thin films led to a significant enhancement in the carrier mobilities (hole and electron mobilities of 0.066 and 0.115 cm/(V·s), respectively, for 200 °C annealing) and thus significantly improved photoresponsive properties. The 200 °C-annealed phototransistors showed a wide-range wavelength (405-850 nm) of photoresponse, and a high photocurrent/dark-current ratio of 150 with a fast photoswitching speed of less than 100 ms. This work demonstrates that a dual acceptor-containing low band gap polymer can be an important class of material in broadband photoresponsive transistors, and the crystallinity of the semiconducting polymer layer has a significant effect on the photoresponse characteristics.