Efficiency improvement using bis(trifluoromethane) sulfonamide lithium salt as a chemical additive in porphyrin based organic solar cells

Abstract

Two new conjugated acceptor-π-donor-π-acceptor (A-π-D-π-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 donors along with PCBM as the acceptor for solution-processed bulk heterojunction organic solar cells. The devices based on 1a:PCBM (1 : 2) and 1b:PCBM (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 vol% of a pyridine additive in THF, the PCE was enhanced up to 5.14% and 6.06% for 1a:PCBM and 1b:PCBM, respectively. Moreover, when we used LiTFSI as the chemical additive in pyridine/CB-processed 1b:PCBM an excellent PCE of 7.63% was recorded. The effects over the film morphology and the device characteristics (J, V and FF) due to the introduction of LiTFSI are discussed.

Conjugated D–A porphyrin dimers for solution-processed bulk-heterojunction organic solar cells

“…[3][4][5][6][7] Since chlorophylls (porphyrin analogues) are natural light-harvesting materials involving photo to energy transfer processes, the study of porphyrins and their analogues on OSCs has been one of the hottest topics since the very early reports on OSC studies. [13][14][15][16][17][18] Also, we still believe that porphyrin-based small molecules should play more roles in OSCs with reasonable structure optimization. 11,12 In recent years, there has been an increasing interest in solution-processed BHJ OSCs using porphyrin derivatives as electron donor materials since we reported conjugated donor-acceptor (D-A) porphyrin donor materials with enhanced PCEs from less than 1% to 9%.…”

Porphyrins and BODIPY as Building Blocks for Efficient Donor Materials in Bulk Heterojunction Solar Cells

“…By using pyridine solvent additive during spin‐casting of the active layer and CuSCN, a quite unusual hole transport layer, instead of common PEDOT:PSS, PCEs of 6.59% and 7.24% were reached for Moran‐1 and Moran‐2, respectively. Few months later, the syntheses of Arrechea‐1 and Arrechea‐2 were described . The first one is an analog to previous Moran‐2 in which thiophene groups in meso position has been substituted with long chain alkoxyphenyl, whereas Arrechea‐2 has dicyanovinylene acceptor unit instead of 3‐ethylrhodanine.…”

“…Few months later, the syntheses of Arrechea-1 and Arrechea-2 were described. [93] The first one is an analog to previous Moran-2 in which thiophene groups in meso position has been substituted with long chain alkoxyphenyl, whereas Arrechea-2 has dicyanovinylene acceptor unit instead of 3-ethylrhodanine. For ITO/PEDOT:PSS/donor:PC 71 BM/Al devices structure, PCEs of 5.14 and 6.06% were measured for Arrechea-1 and Arrechea-2.…”

o,p‐Dimethoxybiphenyl Arylamine Substituted Porphyrins as Hole‐Transport Materials: Electrochemical, Photophysical, and Carrier Mobility Characterization

“…[7] Moreover, their optical properties such as high molecular absorption extinction coefficient (over 10 5 in M -1 cm -1 ) mark porphyrins as excellent candidates for photovoltaic applications. [9] In the latter case, the charge mobility is also a key factor for efficient solar cells together with the superior light harvesting efficiency of porphyrins. Upon addition of chemical dopants, the mobility values increased to 8.8 ± 0.5 × 10 -4 cm 2 /V s, for the zinc porphyrin, and 5.2 ± 0.5 × 10 -4 cm 2 /V s for the free base porphyrin.…”

“…tained very good light-to-energy conversion efficiencies in solar cells such as TiO 2 dye sensitized [8] (also known as Grätzel cells) and/or organic solar cells. [9] In the latter case, the charge mobility is also a key factor for efficient solar cells together with the superior light harvesting efficiency of porphyrins.…”