Helical Polycyclic Heteroaromatic as Hole Transport Material for Perovskite Solar Cell: Remarkable Impact of Alkyl Substitution Position

Abstract

Polycyclic aromatic hydrocarbons play a critical role in the development of organic semiconductors. This study unravels the impact of alkyl substitution position on the molecular energy level, glass transition temperature, diffusion of external species, and hole transport of a pyrrole‐rich, helical polycyclic heteroaromatic, that is TBPC. Compared to terminal substitution, internal hexyl substitution results in steric repulsion with TBPC, weakening π─π stacking and therefore improving thin film morphology. Internal substitution also reduces energy disorder, lowers reorganization energy, and increases intermolecular transfer integrals, leading to enhanced hole mobility. Notably, the organic semiconductor with internal hexyl substitution (TBPC‐611) exhibits a higher molecular packing density, resulting in a markedly higher glass transition temperature and slower diffusion of external species. Using TBPC‐611 as the hole transport material, this work successfully fabricates perovskite solar cells with an average power conversion efficiency above 24%, showing good photostability and thermostability. These findings contribute new insights to the development of high‐performance organic semiconductors.

Recent Advances in Domino Synthesis of Fused Polycyclic N‐Heterocycles Based on Intramolecular Alkyne Hydroamination under Copper Catalysis

“…[14c] In the past 15 years, some series of interesting and potentially useful fused polycyclic N-heterocycles have also been synthesized through domino reactions where copper-catalyzed A 3 coupling meets intramolecular alkyne hydroamination. [18][19][21][22][24][25][26][27][28][29][31][32] Indole moieties are frequently found in natural products, bioactive synthetic molecules and functional materials. [15] The facile and efficient methods for accessing indole-containing N-heterocyclic compounds have aroused great concern.…”

“…In 2009, the Fujii and Ohno group developed a novel copper(I)-catalyzed four-component domino reaction for the assembly of 3-(aminomethyl)isoquinoline-fused polycycic compounds (Scheme 4). [22] A variety of isoquinoline-fused polycyclic N-heterocycles including imidazo[2,1-a]isoquinolines and pyrimido[2,1-a]isoquinolines, which might possess biological effects, were conveniently synthesized through the multi-component reactions of various o-ethynylbenzaldehydes, paraformaldehyde, secondary amines and diamines. Generally, the cyclization/oxidation step could be facilitated under an oxygen atmosphere.…”

Donor engineering of a benzothiadiazole-based D–A–D-type molecular semiconductor for perovskite solar cells: a theoretical study

“…Rational regulation of the components of perovskite materials, surface defect passivation, and the design of new electron- and hole-transporting materials (HTMs) are the main strategies to promote the efficiency and operational stability of the PSCs. 4–6 Among the various HTMs, small molecule HTMs have been largely synthesized to construct durable and cost-effective cell devices. 7–14…”

Tailoring p-Type Charge-Transfer-Doped Hole Transport Layer for All-Inorganic CsPbBr3 Perovskite Solar Cells

“…The photoelectric conversion efficiency (PCE) of organic–inorganic hybrid PSCs has rapidly increased from 3.8 to 26.1% in just a few years due to optimization of the light absorption layer, continuous exploration, and innovation in materials for the hole transport and electron transport layers (ETL) in PSC devices. This achievement brings them closer to the theoretical value and places them on par with leading silicon solar cells. − Unfortunately, hybrid perovskites still suffer from inevitable degradation under air and light induced by the destruction of high polar covalent bonding between the monovalent organic cation and octahedral PbI 2 . − Replacing organic cations in the organic–inorganic hybrid PSCs with inorganic Cs + to generate all-inorganic CsPbX 3 perovskites may improve the stability under environmental pressure. − Among all-inorganic CsPbX 3 perovskites, CsPbI 3 possesses a proper bandgap of 1.73 eV, achieving a high efficiency of approximately 21.75% . However, despite the optimum bandgap, black phase CsPbI 3 still suffers from an imperfect tolerant element triggering a metastable stage steadiness, leading to quick and easy degradation to a nonphotoactive yellow stage with an extensive bandgap of 2.82 eV under an ambient environment …”