Heteroatoms as Rotational Blocking Groups for Non-Fullerene Acceptors in Indoor Organic Solar Cells

Abstract

Organic solar cells are particularly attractive for indoor and low-light applications; however, photocurrents are low under these conditions, and devices are particularly sensitive to the presence of defects and trap states. A rotational blocking group is often added to non-fullerene acceptors to reduce both energetic disorder and the number of defects in the active layer. These blocking groups are most often alkyl chains, which require several synthetic steps to install; this inevitably lowers yields and increases costs. Here we report the addition of heteroatom-based blocking groups to the commonly used non-fullerene acceptor IDIC. These blocking groups are synthetically easy to install and highly effective; bromination leads to significant improvements in the efficiency of PTQ10:IDIC devices under both one-sun and lowlight illumination. In contrast, thioether blocking groups improve efficiency under one-sun illumination but reduce it in dim light, highlighting the need to design and test donor:acceptor systems specifically for indoor applications.

State-of-the-Art of Polymer/Fullerene C60 Nanocomposite Membranes for Water Treatment: Conceptions, Structural Diversity and Topographies

“…It is a hollow ball-like nanostructure having sp 2 hybridized carbon atoms in its architecture [ 24 ]. The carbon atoms in fullerene form a π conjugation system [ 25 , 26 ]. It is made up of unique polygons, i.e., pentagons and hexagons.…”

Design of Dithienopyran-Based Conjugated Polymers for High-Performance Electrochromic Devices

“…The introduction of heteroatoms into the main chain adjusts the electronic properties of conjugated polymers, straightforwardly. − For example, poly­(triarylamine) containing electron-donating methoxy groups (CH 3 O-PTAA) has a higher highest occupied molecular orbital (HOMO) energy level than an oxygen-free polymer film (e.g., CH 3 -PTAA) because of the mesomeric electron-donating ability of methoxy groups at the para positions. This upshifted HOMO energy level of CH 3 O-PTAA promotes its oxidation and doping stability .…”

Systematic Investigation of Core and Endcap Selection on the Development of Functional π-Conjugated Materials

“…21 Generally speaking, improved semiconducting properties are observed in A−D−A systems with an extended π-orbital overlap; this can be achieved by materials that exhibit either a highly planar ring-fused organic backbone or by those that promote conformational locking interactions between heteroatom-containing functional groups in the organic backbone. [1][2][3]22,23 While nearly an infinite number of specialized organic building blocks may be pieced together to make these A−D−A π-conjugated materials, it is important that a reliable, selective, efficient, and atomeconomical synthetic protocol be developed for these materials to ever be produced on the industrial scale. 24,25 With these criteria in mind, the use of direct (hetero)arylation (DHA) to develop these π-conjugated materials has been leveraged as a highly effective cross-coupling method.…”

“…A class of synthetically versatile organic compounds, known as π-conjugated materials, have been extensively used for a number of applications including charge transport/extraction, − light emission, − and even small-molecule catalysis. − Among the numerous π-conjugated material designs, the arrangement of electron-deficient (acceptor) and electron-rich (donor) organic units in an acceptor–donor–acceptor (A–D–A) motif has been popularized owing to the fact that the optical band gap, electron affinity, and/or redox stability can be easily tuned . Generally speaking, improved semiconducting properties are observed in A–D–A systems with an extended π-orbital overlap; this can be achieved by materials that exhibit either a highly planar ring-fused organic backbone or by those that promote conformational locking interactions between heteroatom-containing functional groups in the organic backbone. − ,, While nearly an infinite number of specialized organic building blocks may be pieced together to make these A–D–A π-conjugated materials, it is important that a reliable, selective, efficient, and atom-economical synthetic protocol be developed for these materials to ever be produced on the industrial scale. , With these criteria in mind, the use of direct (hetero)­arylation (DHA) to develop these π-conjugated materials has been leveraged as a highly effective cross-coupling method. Although DHA is highly atom-economic because it avoids the use of organometallic transmetalating groups, it is imperative that organic building blocks are carefully paired to achieve a reliable, efficient, and selective cross-coupling reaction …”