A 9.16% Power Conversion Efficiency Organic Solar Cell with a Porphyrin Conjugated Polymer Using a Nonfullerene Acceptor (original) (raw)
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Dyes and Pigments, 2015
Two new conjugated acceptor-donor-acceptor (A--D--A) compounds having a Znporphyrin acting as donor and linked by ethynylenes to one or two units of thienylenevinylene and capped by dicyanovinylene groups as acceptor units have been synthesized and their photophysical and electrochemical properties were investigated. These compounds were used as donor materials and PC 61 BM and PC 71 BM were used as acceptors in solution-processed bulkheterojunction (BHJ) organic solar cells and the best photoconversion efficiency (PCE) obtained was 3.21%.
Organic Electronics, 2016
Two new conjugated acceptor-donor-acceptor (A--D--A) molecules with a porphyrin core linked by ethynylene bridges to two thiophene (1a) or thienylenevinylenethiophene (1b) units and both capped by N-ethylrhodanine have been synthesized. These compounds were used as the main electron donor moieties for bulk heterojunction small molecule organic solar cells (BHJ-SMOSC). The optimized devices, with PC71BM as the main electron acceptor molecule, show remarkable short circuit currents, up to 13.2 mA/cm 2 , an open circuit voltage of around 0.85 V, and power conversion efficiencies up to 4.3% under 100 W/cm 2. The External Quantum Efficiency (EQE), Atomic Force Microscopy (AFM), hole mobility, Photo-Induced Charge Extraction (PICE) and Photo-Induced Transient Photo-Voltage (PIT-PV) were analyzed in devices based on 1a and 1b in order to account for differences in the final performance of the two molecules. The PIT-PV decays showed slower recombination kinetics for devices fabricated with 1b. Moreover, the EQE was greater for 1b and this is ascribed to the better nanomorphology, which allows better charge collection before carrier recombination takes place.
New Terthiophene Conjugated Porphyrin Donors for Highly Efficient Organic Solar Cells
ACS applied materials & interfaces, 2016
To mimic the natural photosynthetic systems utilizing chlorophylls to absorb light and store light energy, two new porphyrin-based small molecules of PTTR and PTTCNR have been developed for photovoltaic applications. The highest power conversion efficiency of 8.21% is achieved, corresponding to a short-circuit current of 14.30 mA cm-2, open-circuit voltage of 0.82 V, and fill factor of 70.01%. The excellent device performances can be ascribed to the engineering of molecule structure and film morphology. The horizontal conjugation of 3,3''-dihexyl-terthiophene to porphyrin-core with the vertical aliphatic 2-octylundecyl peripheral substitutions, can not only effectively increase the solar flux coverage between the conventional Soret and Q bands of porphyrin unit, but also optimize molecular packing through polymorphism associated with side-chains and the linear π-conjugated backbones. And the additive of 1,8-diiodooctane and subsequent chloroform solvent vapor annealing facil...
The Journal of Physical Chemistry C, 2014
In this report we describe the use of a novel porphyrin triad (PPT) consisting of two zinc-metalated porphyrin units and one free-base porphyrin unit covalently linked through their peripheral amino-phenyl groups to a central s-triazine unit, in combination with PC 70 BM ([6,6]-phenyl C 70 butyric acid methyl ester), as electron donor and electron acceptors, respectively, for the fabrication of small-molecule based, solution-processed, bulk heterojunction (BHJ) organic solar cells. Photoluminescence studies of PPT:PC 70 BM blend films indicated that charge transfer is possible from PPT to PC 70 BM molecules. The solutionprocessed BHJ organic solar cell with the PPT:PC 70 BM blend in 1:1 weight ratio, processed from THF, was found to exhibit an overall power conversion efficiency (PCE) of 2.85%. When the BHJ active layer of PPT:PC 70 BM was processed from a 5% v/v mixture of 1-chloronaphathalene (CN) in THF, the PCE of the solar cell was increased up to 3.93%. This was attributed to the enhancement of the short circuit current J sc of the solar cell, which was ascribed to a stronger and broader incident photon to current efficiency (IPCE) response and to the higher degree of crystallinity of the active layer of the latter solar cell. The different surface morphologies of the two differently processed active layers result in different electron transport kinetics, and, as shown by electrochemical impedance spectra (EIS) and relaxation time measurements, the device with the active layer with the higher degree of crystallinity results in faster charge transfer process and more efficient exciton dissociation at the PPT/PC 70 BM interface.
Nanoscale, 2016
Two new conjugated acceptor--donor--acceptor (A--D--A) porphyrins have been synthesised using 3-ethylrhodanine (1a) or dicyanovinylene (1b) groups as acceptor units. Their optical and electrochemical properties made these materials excellent electron donor along PC71BM as acceptor for solution-processed bulk heterojunction organic solar cells. The devices based on 1a:PC71BM (1:2) and 1b:PC71BM (1:2) processed with CB showed low power conversion efficiencies (PCE) of 2.30% and 2.80%, respectively. Nonetheless, after processing the active layer using a mixture of 3 v% of pyridine additive in THF, the PCE was enhanced up to 5.14% and 6.06% for 1a:PC71BM and 1b:PC71BM, respectively. Moreover, when we used LiTFSI as chemical additive in pyridine/CB-processed 1b:PC71BM an excellent PCE of 7.63% was recorded. The effects over the film morphology and the device characteristics (Jsc, Voc and FF) by the introduction of LiTFSI are discussed.
Nanoscale, 2016
Two new conjugated acceptor--donor--acceptor (A--D--A) porphyrins have been synthesised using 3-ethylrhodanine (1a) or dicyanovinylene (1b) groups as acceptor units. Their optical and electrochemical properties made these materials excellent electron donor along PC71BM as acceptor for solution-processed bulk heterojunction organic solar cells. The devices based on 1a:PC71BM (1:2) and 1b:PC71BM (1:2) processed with CB showed low power conversion efficiencies (PCE) of 2.30% and 2.80%, respectively. Nonetheless, after processing the active layer using a mixture of 3 v% of pyridine additive in THF, the PCE was enhanced up to 5.14% and 6.06% for 1a:PC71BM and 1b:PC71BM, respectively. Moreover, when we used LiTFSI as chemical additive in pyridine/CB-processed 1b:PC71BM an excellent PCE of 7.63% was recorded. The effects over the film morphology and the device characteristics (Jsc, Voc and FF) by the introduction of LiTFSI are discussed.