Cu and Zn based phthalocyanines with 4-tert-octylphenoxy-substituted functional groups were synthesized and showed high solubility in a range of organic solvents, they were integrated in perovskite solar cells.

Dopant-free metal phthalocyanines are viable alternatives to the classical Spiro-OMeTAD in perovskite solar cells (PSCs), due to their appealing optoelectrical properties and chemical stability. However, low carrier concentration, transportability, and narrow bandgap limit their application. Here, we designed and investigated six innovative asymmetrically substituted metal phthalocyanines (MPcs, M = Zn or Cu), and established the correlation between electronic structure, charge carrier transfer parameter, and core metal/substitutions in MPcs by transient absorbance spectroscopy and electronic paramagnetic resonance. We probed the charge transport properties of ZnPcs including carrier lifetime, diffusion coefficient, and diffusion length by transient absorbance spectroscopy. We noted, ZnPcAE presents a longer diffusion length (1.94 nm) than of control ZnPcTB4 (0.80 nm), which is advantageous for reducing charge recombination and gave higher power conversion efficiency in the fabricated PSCs. Importantly, the devices with MPcs yielded improved stability under multi-stress conditions. Our work provides a molecular guideline for designing MPcs and their application as dopant-free hole-transporting materials for perovskite solar cells fabrication.

Fluorinated zinc and copper metallophthalocyanines MPcF 48 are synthesized and incorporated as third component small molecules in ternary organic solar cells (TOSCs). To enable the high performance of TOSCs, maximizing short-circuit current density (J SC ) is crucial. Ternary bulk heterojunction blends, consisting of a polymer donor PTB7-Th, fullerene acceptors PC 70 BM, and a third component MPcF 48 , are formulated to fabricate TOSCs with a device architecture of ITO/PFN/active layer/V 2 O 5 /Ag. Employing copper as metal atom substitution in the third component of TOSCs enhances J SC as a result of complementary absorption spectra in the near-infrared region. In combination with J SC enhancement, suppressed charge recombination, improved exciton dissociation and charge carrier collection efficiency, and better morphology lead to a slightly improved fill factor (FF), resulting in a 7% enhancement of PCE than those of binary OSCs. In addition to the increased PCE, the photostability of TOSCs has also been improved by the appropriate addition of CuPcF 48 . Detailed studies imply that metal atom substitution in phthalocyanines is an effective way to improve J SC , FF, and thus the performance and photostability of TOSCs.

A supramolecular triad composed of a fused zinc phthalocyanine‐free‐base porphyrin dyad (ZnPc‐H2P) coordinated to phenylimidazole functionalized C60 via metal‐ligand axial coordination was assembled, as a photosynthetic antenna‐reaction centre mimic. The process of self‐assembly resulting into the formation of C60Im:ZnPc‐H2P supramolecular triad was probed by proton NMR, UV‐Visible and fluorescence experiments at ambient temperature. The geometry and electronic structures were deduced from DFT calculations performed at the B3LYP/6‐31G(dp) level. Electrochemical studies revealed ZnPc to be a better electron donor compared to H2P, and C60 to be the terminal electron acceptor. Fluorescence studies of the ZnPc‐H2P dyad revealed excitation energy transfer from 1H2P* to ZnPc within the fused dyad and was confirmed by femtosecond transient absorption studies. Similar to that reported earlier for the fused ZnPc‐ZnP dyad, the energy transfer rate constant, kENT was in the order of 1012 s−1 in the ZnPc‐H2P dyad indicating an efficient process as a consequence of direct fusion of the two π‐systems. In the presence of C60Im bound to ZnPc, photoinduced electron transfer leading to H2P‐ZnPc.+:ImC60.− charge separated state was observed either by selective excitation of ZnPc or H2P. The latter excitation involved an energy transfer followed by electron transfer mechanism. Nanosecond transient absorption studies revealed that the lifetime of charge separated state persists for about 120 ns indicating charge stabilization in the triad.

A new zinc phthalocyanine-zinc porphyrin dyad (ZnPc-ZnP) fused through a pyrazine ring has been synthesized as a receptor for imidazole-substituted C (CIm) electron acceptor. Self-assembly via metal-ligand axial coordination and the pertinent association constants in solution were determined by H-NMR, UV-Vis and fluorescence titration experiments at room temperature. The designed host was able to bind up to two CIm electron acceptor guest molecules to yield CIm:ZnPc-ZnP:ImC donor-acceptor supramolecular complex. The spectral data showed that the two binding sites behave independently with binding constants similar in magnitude. Steady-state fluorescence studies were indicative of an efficient singlet-singlet energy transfer from zinc porphyrin to zinc phthalocyanine within the fused dyad. Accordingly, the transient absorption studies covering a wide timescale of femto-to-milli seconds revealed ultrafast energy transfer from ZnP* to ZnPc (k ∼ 10 s) in the fused dyad. Further, a photo induced electron transfer was observed in the supramolecularly assembled CIm:ZnPc-ZnP:ImC donor-acceptor complex leading to charge separated states, which persisted for about 200 ns.