Highly efficient and thermally stable fullerene-free organic solar cells based on a small molecule donor and acceptor

Abstract

We studied fullerene-free organic solar cells using rhodanine-terminated BDT3TR and O-IDTBR.

A Halogenation Strategy for over 12% Efficiency Nonfullerene Organic Solar Cells

“…To date, NFAs with A–D–A structure have earned great success and PCEs over 13% have been achieved . The design strategies of A–D–A‐type NFAs are focused on two aspects: the donor core units and the acceptor end‐groups, aiming to tune the energy levels, absorption, and even packing modes in the active layers. In contrast to the various core units for the A–D–A‐type NFAs, only a few end‐groups such as 2‐(2,3‐dihydro‐3‐oxo‐1H‐inden‐1‐ylidene)propanedinitrile (INCN) and rhodanine and their derivatives have been reported .…”

“…The design strategies of A–D–A‐type NFAs are focused on two aspects: the donor core units and the acceptor end‐groups, aiming to tune the energy levels, absorption, and even packing modes in the active layers. In contrast to the various core units for the A–D–A‐type NFAs, only a few end‐groups such as 2‐(2,3‐dihydro‐3‐oxo‐1H‐inden‐1‐ylidene)propanedinitrile (INCN) and rhodanine and their derivatives have been reported . The optimization of end‐groups, especially delicate modification of the successful end‐group INCN has been proved to exert great influence not only on the energy levels, but also on the intra‐ and intermolecular packing states of the NFAs …”

All-Small-Molecule Organic Solar Cells Based on a Fluorinated Small Molecule Donor With High Open-Circuit Voltage of 1.07 V

“…Using polymer donor materials, both single junction and tandem OSCs have achieved the impressive power conversion efficiencies (PCEs) of 15-18% (Meng et al, 2018;An et al, 2019;Fan et al, 2019;Lin et al, 2019;Wu Y. et al, 2019;Xiong et al, 2019;Yan et al, 2019). So far, all-small-molecule OSCs (ASM-OSCs), i.e., devices based on both small molecule donor and acceptor, have shown relatively lower performance compared with that of polymer donor based devices (Zhang Q. et al, 2014;Kan et al, 2015;Badgujar et al, 2016;Yang et al, 2017;Privado et al, 2018;Wang et al, 2018a;Duan et al, 2019). Nevertheless, with the advantages of versatile molecules design, less variation among different batches and thus easiness of property control for small molecules, ASM-OSCs are strongly believed to have the potential to achieve and even surpass the performance of polymer donor counterparts (Chen et al, 2013).…”

Efficient Organic Solar Cells with Non‐Fullerene Acceptors

“…Currently, the most popular strategy is to construct A‐D‐A (Acceptor‐Donor–acceptor) planar molecular structures, which is first developed by Zhan et al through employing the fused ladder type donor moieties with 2‐(3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (IC) acceptor . It opens up the flexible design of new electron acceptors with good optoelectronic tunabilities . At present, the best performing fullerene‐free OSCs (with efficiencies over 10%) are generally achieved with A‐D‐A type small molecules, and the highest efficiencies are beyond 12% .…”