Surface crystallinity enhancement in organic solar cells induced by spinodal demixing of acceptors and additives

Abstract

Although non-volatile additives like 1,8-diiodooctane (DIO) and 1-chloronaphthalene (CN) are beneficial to improve power conversion efficiency (PCE) of organic solar cells (OSCs), the effects of such additives on phase evolution...

Additive-assisted strategy for high-efficiency organic solar cells

“…2). 75 They found that a highly ordered surface formed in the 1st sub-layer (top surface) of PBDB-T:ITIC with DIO, which didn’t appear in PM6:Y6 with 1-CN. They attributed this to different demixing modes between acceptors and additives.…”

Halogenation Strategy of Thiophene Derived Solvent Additives Enables Optimized Morphology for Organic Solar Cells with 19.17% Efficiency

“…[41,42] For instance, incorporating a minute amount of high boiling-point liquid additive into the primary solvent can induce various beneficial effects. These include the enhancement of molecular crystallinity and packing within active layer materials, leading to red-shifted absorption and superior energy organization, [43] heightened domain purity coupled with precisely modulated phase separation for improved exciton dissociation and charge transfer properties, [44,45] and potentially the fine-tuned vertical phase distribution of components to optimized charge transport and collection. [46] Typically, the liquid additives employed in efficient OSCs based on Y-SMAs can be classified into the three primary categories: i) dual-halogenated alkanes (e.g., diiodomethane [47] and 1,8-diiodooctane [48] ), ii) multi-halogenated benzene derivatives (e.g., 1,3-diiodobenzene ether and 1,3-dibromobenzene [49,50] ), and iii) mono-halogenated naphthalene derivatives (e.g., 1fluoronaphthalene and 1-chloronaphthalene [51] ).…”

Synergistically optimizing the optoelectronic properties and morphology using a photo-active solid additive for high-performance binary organic photovoltaics

“…Among these, additive engineering is a simple and effective method to optimize the morphology of the active layer. 23–25 Initially, liquid additives, such as 1,8-diiodooctane (DIO) 26 and 1-chloronaphthalene (1-CN), 27 were proposed, which became a prevailing strategy to modulate the phase-separation process and achieve an ideal morphology and high efficiency. Recently, significant attention has been focused on solid additives, which are more efficient in manipulating phase separation and crystallization kinetics.…”