Trifluoromethylation Enables a 3D Interpenetrated Low-Band-Gap Acceptor for Efficient Organic Solar Cells

Abstract

Herein, trifluoromethylation has proven to be an effective strategy for ultra-narrow band-gap NFAs. A PCE of 15.59% is achieved from BTIC-CF 3 -g-based devices, which is the highest value in reported ultra-narrow band-gap acceptors. A ternary device with 16.50% efficiency is also obtained, resulting from its red-shifted absorption. Meanwhile, the single-crystal structure of BTIC-CF 3 -g has been successfully presented, which gives a deep understanding of the solid-state molecular packings in these highly efficient acceptors.

Delocalization of exciton and electron wavefunction in non-fullerene acceptor molecules enables efficient organic solar cells

“…Although these material and device engineering strategies are effective in improving Y6-based OSCs, there were few research efforts that focused on revealing the origin of the remarkable performances enabled by this molecular design 34 . It has been proposed that studies of the single-crystal structure of Y6-based molecules could be useful in revealing the intrinsic properties of the acceptor 25 , 35 . However, to better evaluate the structure-property relationship of the OSCs, the molecular packing of the acceptor in the BHJ film and how such packing can affect the electronic processes at the acceptor/donor interface need to be studied in order to provide better understanding on the origin of the high-performance devices.…”

Crystal Engineering in Organic Photovoltaic Acceptors: A 3D Network Approach

“…[ 37 ] In this review, we have summarized the chemical structures of FREAs including PDI‐type acceptors, [ 36,38 ] A‐D‐A‐type [ 37,39–53 ] and A‐DAD‐A‐type acceptors. [ 54–57 ] The relationships among molecular design, packing structures and corresponding properties are discussed in details. Ordered J‐aggregate arrangements induced by chlorination are revealed [ 40 ] and the influences of the substituted position and numbers of halogen atoms on the molecular packing are summarized.…”

“…[ 37,48 ] The effects of alkyl chains, core size, and molecular shape on the aggregation states is explored, [ 44,46,47,51,53 ] and the isomerization of PDIs on molecular packing arrangements and its photovoltaic effects are reviewed. [ 38 ] The differences of packing structures in the A‐D‐A and A‐DAD‐A type acceptors are noted [ 57 ] and several different intermolecular interactions including Cl∙∙∙S, Cl∙∙∙π, Br∙∙∙S, N∙∙∙F and N∙∙∙S are also described. [ 54–55,57 ] More importantly, the 3D network packing which was first reported by our group [ 37 ] in a Cl‐substituted isomers system.…”

“…[ 38 ] The differences of packing structures in the A‐D‐A and A‐DAD‐A type acceptors are noted [ 57 ] and several different intermolecular interactions including Cl∙∙∙S, Cl∙∙∙π, Br∙∙∙S, N∙∙∙F and N∙∙∙S are also described. [ 54–55,57 ] More importantly, the 3D network packing which was first reported by our group [ 37 ] in a Cl‐substituted isomers system. In organic semiconductors, the charge transfer between two adjacent molecules was usually realized by the ππ hopping due to the overlap of π‐orbitals.…”

Boron(iii) β-diketonate-based small molecules for functional non-fullerene polymer solar cells and organic resistive memory devices

“…2f), in which isotropic electron transport could be envisaged. [49][50][51] The single crystal structure of compound 1 and its packing not only suggest the favorable packing motif for the potential application of the BF 2 bdk-based acceptor moiety in constructing A-D-A type NFAs, but also provide for the rst time molecular geometry insights into A-D-A type NFAs with a central tricyclic donor moiety.…”