Low conductivity and hole mobility in the pristine metal phthalocyanines greatly limit their application in perovskite solar cells (PSCs) as the hole‐transporting materials (HTMs). Here, we prepare a Ni phthalocyanine (NiPc) decorated by four methoxyethoxy units as HTMs. In NiPc, the two oxygen atoms in peripheral substituent have a modified effect on the dipole direction, while the central Ni atom contributes more electron to phthalocyanine ring, thus efficiently increasing the intramolecular dipole. Calculation analyses reveal the extracted holes within NiPc are mainly concentrated on the phthalocyanine core induced by the intramolecular electric field, and further to be transferred by π‐π stacking space channel between NiPc molecules. Finally, the best efficiency of PSCs with NiPc as dopant‐free HTMs realizes a record value of 21.23 % (certified 21.03 %). The PSCs also exhibit the good moisture, heating and light stabilities. This work provides a novel way to improve the performance of PSCs with free‐doped metal phthalocyanines as HTMs.
We
provide a visualization method to observe the photoinduced charge
transfer and electron–hole coherence in the two-photon absorption
(TPA), especially including the optical properties in the “hidden”
intermediate states in TPA. A new method for analyzing the characteristics
of two-photon excitation is proposed using a two-step process, which
is closest to the physical reality process. These visualization methods
include transition density matrix, charge density difference, and
transition dipole moment in TPA involving both ground and excited
state wavefunctions and the transition dipole moments among electric
transitions from ground to intermediate and to final excited states.
Our visualization method of photoinduced CT and electron–hole
coherence in TPA can promote deeper understanding and design molecules
with large cross sections in TPA.
Grain boundary management is critical to the performance and stability of polycrystalline perovskite solar cells (PSCs), especially large-area devices. However, typical passivators are insulating in nature and limit carrier transport. Here, we design a supramolecular binder for grain boundaries to simultaneously passivate defects and promote hole transport across perovskite grain boundaries. By doping the monoamine porphyrins (MPs, M = Co, Ni, Cu, Zn, or H) into perovskite films, MPs self-assemble into supramolecules at grain boundaries. Organic cations in perovskites protonate MPs in supramolecules to form ammonium porphyrins bound on the perovskite grain surface, to passivate defects and extract holes from the perovskite lattice. Periodic polarons in supramolecules (especially NiP-supramolecule) promote the transport of extracted holes across boundaries, reducing nonradiative carrier recombination. The NiP-doped PSCs reveal a certified efficiency of 22.1% for an active area of 1.0 cm 2 with the remarkably improved open-circuit voltage and fill factor. The unencapsulated device retained over 80% initial performance under AM 1.5G solar light continuous illumination or heating at 85 °C over 3000 h.
The multi-scale computational method of combining the first-principles calculation and finite element electromagnetic simulations is used to study the plasmon-enhanced interlayer charge transfer (CT) exciton of 2D lateral and van der Waals MoS2/WS2 heterostructures with the 2H phase. The weak interlayer CT excitons are observed in the 2H lateral and van der Waals MoS2/WS2 heterostructures. Theoretical results reveal the physical principle of plexcitons resulting from the strong coupling between plasmons and interlayer CT excitons. The weak CT excitons can be strongly enhanced by a metal plasmon, which provides a way to observe the weak CT excitons. Our results can promote a deeper understanding of the plexciton resulting from strong coupling interaction between the plasmon and the exciton of lateral and van der Waals heterostructures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.