A water/alcohol-soluble conjugated porphyrin small molecule as a cathode interfacial layer for efficient organic photovoltaics

Abstract

A water/alcohol-soluble conjugated porphyrin small molecule exhibits very good ability as a cathode interfacial material in organic solar cells.

Molecular design of interfacial layers based on conjugated polythiophenes for polymer and hybrid solar cells

“…The BHJ composite is usually deposited from apolar organic solvents; it is therefore advantageous that the IL material is soluble in water or alcohols. Small molecule analogues of chlorophylls, porphyrins and their derivatives have been intensively investigated as IL materials due to their large π‐conjugated planar structures and easy chemical modifications of the peripheries to improve the intramolecular charge transport and electron transfer . For example, Zhang et al developed a CIL based on a water‐soluble conjugated porphyrin, FNEZnP‐OE , in which two amino‐functionalized fluorenes are linked to a porphyrin core by ethynyl linkages (Scheme 2) .…”

“…Small molecule analogues of chlorophylls, porphyrins and their derivatives have been intensively investigated as IL materials due to their large π‐conjugated planar structures and easy chemical modifications of the peripheries to improve the intramolecular charge transport and electron transfer . For example, Zhang et al developed a CIL based on a water‐soluble conjugated porphyrin, FNEZnP‐OE , in which two amino‐functionalized fluorenes are linked to a porphyrin core by ethynyl linkages (Scheme 2) . A conventional device incorporating the CIL and based on a PTB7‐Th : PC 71 BM active layer exhibited a PCE of 9.16%, which was a 41% increase compared to the device with no CIL (6.5%) .…”

“…For example, Zhang et al developed a CIL based on a water‐soluble conjugated porphyrin, FNEZnP‐OE , in which two amino‐functionalized fluorenes are linked to a porphyrin core by ethynyl linkages (Scheme 2) . A conventional device incorporating the CIL and based on a PTB7‐Th : PC 71 BM active layer exhibited a PCE of 9.16%, which was a 41% increase compared to the device with no CIL (6.5%) . The improvement was attributed to a decrease in the WF of the cathode through the surface dipole interaction with the amino‐functionalized polar side groups, with the extended π‐conjugated backbone of FNEZnP‐OE due to the ethynyl linkages thought to be beneficial for enhanced electron transport.…”

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

“…The onset oxidation (E ox ) and reduction (E red ) potentials of (DPP-ZnP-E)2 were 0.66 and À0.94 V vs. Fc/Fc + , respectively ( Fig. 28 The current density-voltage ( J-V) curves of the optimized devices are shown in Fig. Also, the HOMO and LUMO energy levels were estimated to be À4.87 and À3.21 eV for (DPP-ZnP-E)2-2T, and À5.03 and À3.34 eV for (DPP-ZnP-E)2-Ph, respectively.…”

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

“…One original concept in this work is the use of a cathode interlayer, FNEZnP‐OE, which consists of a porphyrin core functionalized by two 9,9‐bis(30‐ N , N ‐dimethylamino)propyl)‐2,7‐fluorene units. This compound was previously described and found to be more efficient as electron transport layer than well‐known PFN . Optimized cells showed PCEs of 4.50, 5.50, and 6.42% for (DPP‐ZnP‐E)2, (DPP‐ZnP‐E)2‐2T, and (DPP‐ZnP‐E)2‐Ph, respectively, using ITO/PEDOT:PSS/donor:PC 61 BM/FNEZnP‐OE/Al structure.…”