Largely Enhanced Efficiency with a PFN/Al Bilayer Cathode in High Efficiency Bulk Heterojunction Photovoltaic Cells with a Low Bandgap Polycarbazole Donor

Simultaneous Enhancement of Open‐Circuit Voltage, Short‐Circuit Current Density, and Fill Factor in Polymer Solar Cells

“…[18][19] Besides the methods described above, it was reported by our group that alcohol/water-soluble polymer cathode interlayers can enhance V OC of PSCs prepared from polyfl uorene and polycarbazole derivatives. [20][21][22] In parallel, other polyelectrolytes have also been reported to have similar functions, [ 23 , 24 ] and in particular the Bazan group improved the effi ciency of PSCs based on poly[ N -9´´-hepta-decanyl-2,7-carbazole-alt-5,5-(4´,7´-di-2-thienyl-2´,1´,3´-benzothiadiazole) (PCDTBT) to 6.5% via incorporation of a conjugated polyelectrolyte interlayer. [ 25 ] Although it is indispensable to obtain simultaneous enhancement in V OC , J SC , and FF in order to push the PCE of PSCs towards their theoretical limit ( ≈ 10%), [ 26 ] there are few methods so far in the literature that are able to simultaneously improve all three parameters towards realization of the high effi ciency of 10%.…”

Enhanced Open‐Circuit Voltage in High Performance Polymer/Fullerene Bulk‐Heterojunction Solar Cells by Cathode Modification with a C60 Surfactant

“…One method involves deliberate inclusion and/ or tuning of a dipole layer to improve alignment between the Fermi level (E F ) of the contact and the appropriate frontier molecular orbital level of the organic, while another entails insertion of a thin layer of polymer surfactant to reduce contact resistance. [15][16][17][18] In conventional BHJ-based PSCs, the conducting polymer poly(ethylenedioxythiophene):poly(styrenesulf onate) (PEDOT:PSS) is used to modify the surface of the hole-collecting anode. With a work function (WF) closely matching the holetransport level of a wide range of donor polymers, of the order of 5 eV below vacuum, PEDOT:PSS is capable of forming excellent electrical contact with the organic active layer of the device at the anode.…”

Blue photoluminescence N-substituted poly(4H-benzo[def]carbazole)s

“…2,6-Dibrominated ECz (3) was synthesized by reductive ring closure of 2 that was prepared by nitration of 1 according to the procedures reported previously (Scheme 1 see Supporting information ) [19]. Reagents and solvents were purchased from Kanto Chemical, Tokyo Chemical Industry, Aldrich and Nacalai Tesque Inc. Dimethylformamide (DMF) and benzene distilled after drying with CaH2 were stored under an argon atmosphere.…”