Narrow-Band-Gap Conjugated Polymers Based on 2,7-Dioctyl-Substituted Dibenzo[a,c]phenazine Derivatives for Polymer Solar Cells

Abstract

A series of new 2,7-dioctyl-substituted dibenzo[a,c]phenazine (BPz) derivatives were designed and synthesized as electron-deficient units, which were copolymerized with an electron-rich indacenodithiophene (IDT) to construct narrow-bandgap copolymers PIDT−OHBPz, PIDT−OFBPz, and PIDT−OBPQ via Stille polycondensation. The 2,7-dioctyl substituents enhanced solubility and offered a new approach for developing various BPz derivatives. All copolymers showed high hole mobilities above 0.01 cm 2 V −1 s −1 as measured by field effect transistors. The best performance of polymer solar cell was achieved based on PIDT−OFBPz with inverted device structure of ITO/ZnO/PFN/polymer:PC 61 BM/MoO 3 /Al, which showed an opencircuit voltage (V oc ) of 0.97 V, a short-circuit current (J sc ) of 8.96 mA/cm 2 , and a fill factor (FF) of 58.99%, leading to a high power conversion efficiency (PCE) of 5.13%. These results indicate that 2,7-alkyl-substituted BPz derivatives can be used as an excellent electron-deficient building block for the construction of high-performance organic electronic materials.

Soluble fluorescent polymeric nanoparticles based on pyrrole derivatives: synthesis, characterization and their structure dependent sensing properties

“…Fig. 43,44 N-substituted PPys are among the most studied derivatives of PPy. The results of size and molecular weight for PPy nanoparticles have been summarized in Table 1.…”

A Novel Alkylated Indacenodithieno[3,2‐b]thiophene‐Based Polymer for High‐Performance Field‐Effect Transistors

“…However, further improvement of the field‐effect mobility of IDT polymers by structure modification remains elusive thus far. For example, changing the alkyl side‐chains on the IDT to phenyl alkyl groups reduced the reported charge carrier mobility, whilst retaining the linear alkyl side‐chains and varying the comonomer has also reduced charge carrier mobility in all reported examples . Changing the bridging atoms on the IDT unit from carbon to silicon or germanium also resulted in a reduction of the reported charge carrier mobility …”

Impact of the Catalytic System on the Formation of Structural Defects for the Synthesis of Well‐Defined Donor–Acceptor Semiconducting Polymers

“…In this work, we study the effect of the most commonly used catalytic systems, such as Pd 2 (dba) 3 in combination with the organic ligands of tri( o ‐tolyl)phosphine [( o ‐CH 3 Ph) 3 P] or triphenylphosphine (PPh 3 ) and the ligand‐free catalyst Pd(PPh 3 ) 4 , on the synthesis of D–A conjugated polymers consisting of the indacenodithiophene (IDT) as the electron donating unit and the bis(3‐octyloxy)phenyl)quinoxaline (Qx) derivative as electron withdrawing moiety, through Stille cross‐coupling reaction ( Figure ). The selection of this particular polymeric system was made due to the fact that the D–A conjugated polymers based on IDT and Qx derivatives have demonstrated great promise as p ‐type polymers in organic photovoltaics as they considered desirable components for ternary or tandem solar cells due to their high power conversion efficiency (PCEs) . Moreover, this particular combination of IDT and Qx offers clear and distinguished nuclear magnetic resonance (NMR) chemical shifts at ≈3.7 ppm, assigned to the (CH 2 O) alkoxy side chains protons of Qx and at ≈2.5 ppm, assigned to the (CH 2 ) aliphatic protons next to the phenyl substituents of IDT (please see the Results and Discussion section in the text), which enable us to calculate the composition ratio of the D and A moieties in the polymer backbone and to visualize other NMR chemical shift signals of low intensity which can be attributed to structural defects (homocoupling) among the macromolecular main chain.…”