Trifluoromethyl Substituted Derivatives of Pyrazoles as Materials for Photovoltaic and Electroluminescent Applications

Abstract

New 6-CF3-1H-pyrazolo[3,4-b]quinolines with a methyl and/or phenyl group attached to the pyrazole core (Molx (x = 1, 2, 3, 4)) were synthesized and characterized in terms of their optoelectronic applications: photovoltaic and electroluminescence. The fluorescence emissions of the investigated phenyl-decorated pyrazoloquinolines is caused by the photoinduced charge transfer p process occurring between the phenyl substituent and the pyrazoloquinoline core, while 1,3-dimethyl-6-CF3-1H-pyrazolo[3,4-b]quinoline exhibits an π,π*-type emission. The number of phenyls and their substitution positions modulate both emission properties and HOMO energy levels. Next, the bulk heterojunction BHJ solar cells based on 1H-pyrazolo[3,4-b] quinoline derivatives with architecture ITO/PEDOT:PSS/PDT + Molx/Al were fabricated. The organic active layer was a blend of Molx and poly(3-decylthiophene-2,5-diyl). The complex refractive index and the layer thickness of the organic solar cells were determined using a spectroscopic ellipsometer Woollam M2000 (J.A. Woollam Co., Inc., Lincoln, NE, USA) and CompleteEASE software. For solar devices with the best value of power efficiency of approximately 0.38%, the thickness of the active layer (Mol3 + PDT) was 111 nm, with a short-circuit current density of JSC = 32.81 μA/cm2 and an open–circuit voltage of VOC = 0.78 V. Finally, we demonstrated double-layer light-emitting diodes with an organic active layer (Molx + PVK) and an electron transporting material layer, ETM (2-[3,5-bis(4-phenyl-2-quinolyl)phenyl]-4-phenylquinoline (Tris-Q). Bright bluish-green light originating from the active layer was observed in the double-layer device, ITO/PEDOT:PSS/active layer/ETM/Ca/A. The active layer was a mixture of PV-doped 1H-pyrazolo[3, 4-b]quinoline dyes. An OLED device was constructed by employing Molx as an emitter, which gave a deep bluish-green emission with the spectra range of 481–506 nm. The best value of the maximum brightness at approximately 1436.0 cd/m2 was achieved for a diode based on Mol3 (1-phenyl-3-phenyl-6-CF3-1H-pyrazolo[3,4-b]quinoline) and [R1 = Ph, R3 = Ph and R6 = CF3]. The current efficiency was up to 1.26 cd/A at 506 nm with a CIE of 0.007, 0.692.

Organic LEDs Based on Bis(8-hydroxyquinoline) Zinc Derivatives with a Styryl Group

“…Finally, a 100 nm thick aluminum (Al) layer was deposited on the ITO/PEDOT:PSS/ZnStq_R:PVK structure via vacuum vapor deposition under medium vacuum conditions (10 −6 bar) [38]. The obtained OLED (ITO/PEDOT:PSS/ZnStq_R:PVK/Al) with an active ZnStq_R:PVK layer of about 24 mm 2 was fabricated as presented in [39].…”

Polyplatinaynes Functionalized with Pyrazoline Derivatives

“…Therefore, the pyrazoline derivatives are expected to be used as a new type of optoelectronic materials in a broader field of applications. On the other hand, the electron-rich pyrazoles are an important class of nitrogencontaining five-membered heterocycles and show a range of applications in medicine, dye-sensitized solar cells and second-order NLO [18][19][20][21][22][23][24][25]. To our knowledge, there are no reports on exploiting pyrazoline and its pyrazole derivatives in the preparation of organometallic polyynes.…”

Efficient Synthesis of Fully Substituted and Diversely Functionalized Pyrazoles through p‐TSA Catalyzed One‐Pot Condensation of Cyclic β‐Diketones, Arylglyoxals and Arylhydrazones

“…Some of the best‐selling pyrazole‐based commercial drugs are celecoxib, [5a] crizotinib, [5b] difenamizole, [5c] ruxolitinib, [5d] cefoselis, [5e] and pyraclostrobin [5f] . Recently, the aryl‐substituted pyrazoles are observed to play crucial role as cannabinoid (CB1) receptor ligand, [6a] antimicrobial agent, [6b] p38 MAP kinase inhibitor, [6c] and photovoltaic and electroluminescent probe [6d] . Moreover, a number of synthesized pyrazole derivatives possess prominent photophysical properties, and are used as important tool for colorimetric and fluorometric detection of heavy metal ions [7] .…”