Proses Produksi Dan Pengemasan Yoghurtdicv. Cita Nasional Salatiga

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Siloxane-Terminated Side Chain Engineering of Acceptor Polymers Leading to Over 7% Power Conversion Efficiencies in All-Polymer Solar Cells

To investigate the influence of functional pendent groups on acceptor polymers and photovoltaic properties of all-polymer solar cells (all-PSCs), two novel acceptor polymers containing siloxane-terminated side chains are synthesized and characterized. Increasing the content of siloxane-terminated side chains can reduce π–π stacking distance and improve crystalline behavior, yet lead to poorer solubility of the acceptor polymers. By modulating the proper loadings of siloxane-terminated side chains on the acceptor polymers, the PBDB-T:PNDI-Si25 all-PSC attains a maximal power conversion efficiency (PCE) of 7.4% with an outstanding fill factor of 0.68. The results provide new insights for developing high-performance all-PSCs through functional group engineering on the acceptor polymers, to achieve good solubility, polymer miscibility, and blend morphology

5,6-Difluorobenzothiazole-Based Conjugated Polymers with Large Band Gaps and Deep Highest Occupied Molecular Orbital Levels

A 5,6-difluorobenzothiazole-based dibromo monomer was successfully synthesized, from which new fluorinated conjugated polymers PF-ffBTz and PFN-ffBTz were prepared via copolymerizations with two fluorene-based diboronic ester monomers. Twisted fluorene-ffBTz backbones enable PF-ffBTz and PFN-ffBTz with large band gaps up to 3.10 eV and deep-lying highest occupied molecular orbital levels down to −6.2 eV. The chemical structures of PF-ffBTz and PFN-ffBTz impart some new functionalities of fluorinated conjugated polymers. PF-ffBTz can show deep blue electroluminescent emission, with high external quantum efficiency of 3.71%. PFN-ffBTz, with amino-functionalized side chains on the fluorene unit, can serve as an efficient cathode interlayer in inverted polymer solar cells (PSCs), showing better photovoltaic performances if compared with a ZnO interlayer. In addition, it is found that using an optical filter to cut off the short wavelength section (≤380 nm) of incident light can significantly elevate photostability of PSCs under continuous illumination

Temperature-Driven Phase Transition of a Fused Dithienobenzothiadiazole–Tetrathiophene Based Semiconducting Copolymer

A high-molecular-weight donor–acceptor (D–A) copolymer, pDTfBT-4T, poly­(5,8-di­[3-octyl­dodecan­thiopen-5-yl]­dithieno­[3′,2′:3,4:2″,3″:5,6]­benzo­[1,2-<i>c</i>]­[1,2,5]-thiadiazole-<i>alt</i>-2,2′-bithiophene), including alternating dithieno­[3′,2′:3,4;2″,3″:5,6]­benzo­[1,2-<i>c</i>]­[1,2,5]­thiadiazole (DTfBT) and 3-octyl­dodecyl­tetrathiophene (4T) was synthesized by a Stille coupling polymerization. We found that pDTfBT-4T had a molecular number-average weight of 276 kg mol^–1 and formed unexpectedly strong interchain aggregates in dilute solutions at room temperature, which was similar to those in as-spun thin solid films. pDTfBT-4T thin films were spun-cast from a warm dilute chlorobenzene solution on hydrophobic polymer-treated SiO₂ dielectrics. Some were shortly annealed at various temperatures (<i>T</i>) for 10 min to improve π-overlapped structures as charge-carrier transport paths. The ordered domains of pDTfBT-4T in the annealed films could be tuned from one-dimensional nanorods to two-dimensional nanosheets with an increasing in <i>T</i>, which also provided enhanced crystal orientation. Optimizing the conjugated structures of pDTfBT-4T in the annealed films, the polymer based OFETs yielded a hole mobility up to 1.45 cm² V^–1 s^–1 as well as negligible hysteresis and excellent negative bias stability

High Efficiency and High <i>V</i>_oc Inverted Polymer Solar Cells Based on a Low-Lying HOMO Polycarbazole Donor and a Hydrophilic Polycarbazole Interlayer on ITO Cathode

In this work, poly­[<i>N</i>-9′-heptadecanyl-2,7-carbazole-<i>alt</i>-5,5-(4,7-di-2-thienyl-5,6-bis­(dodecyloxy)-2,1,3-benzothiadiazole)] (PCDTBT12) was synthesized as the polymer donor for photovoltaic application. PCDTBT12 possesses a band gap of 1.99 eV, a low-lying HOMO of −5.6 eV, and good hole mobility up to 4.1 × 10^–3 cm² V^–1 s^–1. With ZnO as the interlayer on an ITO cathode, a PCDTBT12-based inverted solar cell showed a high open-circuit voltage of 0.98 V and a good power conversion efficiency (PCE) of 5.53%, suggesting that PCDTBT12 would be a promising donor material in the fabrication of a subcell for shorter wavelength absorption in a tandem solar cell. Using PC-P, a homopolymer of 2,7-carbazole with hydrophilic phosphonate side chains, as an interlayer polymer on the ITO cathode could further elevate the efficiency to 6.04% because of increased current (higher efficiency of 6.2% was achieved for a smaller cell area of 0.045 cm²). The efficiencies are the highest ones so far reported for an inverted solar cell with an organic cathode interlayer. It was proposed that the hydrophilic side chains of PC-P supplied a subgap state for electron transport. The two devices showed comparable air stability, and retained over 96% of their initial PCEs after storage in air for more than 1 month. Therefore, a hydrophilic conjugated polymer as the cathode interlayer, already shown in outstanding cathode modifications in conventional polymer solar cells, will play an important role in the future development of high efficiency and air-stable inverted solar cells

A Highly Crystalline Wide-Band-Gap Conjugated Polymer toward High-Performance As-Cast Nonfullerene Polymer Solar Cells

A new wide-band-gap conjugated polymer PBODT was successfully synthesized that showed high crystallinity and was utilized as the active material in nonfullerene bulk-heterojunction polymer solar cells (PSCs). The photovoltaic devices based on the as-cast blend films of PBODT with ITIC and IDIC acceptors showed notable power conversion efficiencies (PCEs) of 7.06% and 9.09%, with high open-circuit voltages of 1.00 and 0.93 V that correspond to low energy losses of 0.59 and 0.69 eV, respectively. In the case of PBODT:ITIC, lower exciton quenching efficiency and monomolecular recombination are found for devices with small driving force. On the other hand, the relatively higher driving force and suppressed monomolecular recombination for PBODT:IDIC devices are identified to be the reason for their higher short-circuit current density (<i>J</i>_sc) and higher PCEs. In addition, when processed with the nonchlorinated solvent 1,2,4-trimethylbenzene, a good PCE of 8.19% was still achieved for the IDIC-based device. Our work shows that such wide-band-gap polymers have great potential for the environmentally friendly fabrication of highly efficient PSCs

Donor–Acceptor Copolymers Based on Thermally Cleavable Indigo, Isoindigo, and DPP Units: Synthesis, Field Effect Transistors, and Polymer Solar Cells

A series of donor–acceptor type of π-conjugated copolymers based on <i>tert</i>-butoxycarbonyl (<i>t</i>-Boc) substituted indigo, isoindigo or diketopyrrolopyrrole as the acceptor unit and a benzodithiophene derivative as the donor unit was designed and synthesized. These copolymers can be readily dissolved in organic solvents and can produce uniform films by solution deposition. Thermal treatment of copolymer films at 200 °C for 10 min resulted in elimination of <i>t</i>-Boc side groups in nearly quantitative yield as suggested by thermogravimetric analysis and Fourier transform infrared spectroscopy. The elimination of the bulky <i>t</i>-Boc side groups resulted in the emergence of N–H···OC hydrogen bonding interactions by virtue of the lactam structures of the indigo, isoindigo and diketopyrrolopyrrole units. Of particular interests is the distinctly increased field-effect mobility of these copolymers after thermal treatment, which may arise from the enhanced coplanarity and intermolecular ordering of the indigo, isoindigo or diketopyrrolopyrrole units after elimination of the bulky <i>t</i>-Boc side groups. These results demonstrate that the incorporation of latent side groups provides a viable strategy to construct conjugated polymers that can attain more ordered intermolecular stacking by simple thermal treatments. On the other hand, despite the thermal cleavage of <i>t</i>-Boc groups can also lead to increased ordering of polymer chains when blending with [6,6]-phenyl C71 butyric acid methyl ester, the photovoltaic performances of the resulting bulk heterojunction solar cells did not obviously increase due to the serious phase separation and coarsening of the film morphology