Bulk heterojunction (BHJ) morphologies are vital to the device performance of organic solar cells (OSCs), including phase separation in lateral and vertical directions. However, the morphology developed from the blend solution is not easily predicted and controlled, especially in the vertical direction, because the BHJ morphology is kinetically frozen during the rapid solvent evaporation process. Here, a simple approach to control BHJ morphologies with optimized phase distribution for small molecule:[6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71 BM) blends by enhancing the substrate temperature during the spin‐coating process. Three molecules with various fluorine atoms in the end acceptor units are selected. The relationship among molecular structures, substrate temperature effects on the morphology, and device performances are symmetrically investigated. Low temperature induces a multiple‐sublayer‐like architecture with significantly varied distributions of composition, morphology, and localized state energy, while high processing temperature induces more uniform film. The short‐circuit current, open‐circuit voltage, and fill factor of the devices are tuned with synergic improvement of efficiency toward over 10% and 11% for conventional and inverted devices. This work reveals the origination of vertical phase segregation, and provides a facile strategy to optimize the hierarchical phase separation for enhancing the performance of OSCs.

Transfer of molecular chirality to supramolecular chirality at nanoscale and microscale by chemical self-assembly has been studied intensively for years. However, how such molecular chirality further transfers to the macroscale along the same path remains elusive. Here we reveal how the chirality from molecular level transfers to macroscopic level via self-assembly. We assemble a macrostripe using enantiomeric camphorsulfonic acid (CSA)-doped polyaniline with hierarchical order. The stripe can twist into a single-handed helical ribbon via helical self-motion. A multi-scale chemo-mechanical model is used to elucidate the mechanism underlying its chirality transfer and induction. The molecular origin of this macroscopic helical chirality is verified. Results provide a comprehensive understanding of hierarchical chirality transfer and helical motion in self-assembled materials and even their natural analogues. The stripe exhibits disparate actuation behaviour under stimuli of enantiomeric amines and integrating such chiral perception with helical self-motion may motivate chiral biomimetic studies of smart materials.

Organic photodetectors that can sensitively convert near‐infrared (NIR) circularly polarized light (CPL) into modulable electrical signals have promising applications in spectroscopy, imaging, and communications. However, the preparation of chiral NIR organic photodetectors with simultaneously high dissymmetry factor, responsivity, detectivity, and response speed is challenging. Here, direct CPL detectors based on the bulk heterojunctions (BHJs) of chiral BTP‐4Cl non‐fullerene acceptor with dilute achiral PM6 donor are constructed, which successfully address these issues. The chiral acceptor‐enriched BHJs with a donor/acceptor ratio of 1/10 achieve an optimal trade‐off between chiroptical properties and optoelectronic performance. The supramolecular chirality from the acceptor aggregates provides the BHJs with a true absorption dissymmetry factor (gabs) of ±0.02 at 830 nm, the highest value among NIR‐sensitive detectors, which endows the photodetector with a photocurrent dissymmetry factor (gsc) of ±0.03. Impressively, the photodetector demonstrates an external quantum efficiency as high as 60%, a responsivity of 0.4 A W−1, a detectivity of 3 × 1011 Jones (based on noise current), and a fast response speed on the microsecond scale with the −3 dB bandwidth over 7000 Hz in the NIR region. This study exhibits a promising strategy for building high‐performing direct NIR CPL detectors by introducing supramolecular chirality into BHJs.

Chiral supramolecular architectures deliver desired properties and functions to artificial systems. The recently developed direct circularly polarized light (CPL) detection is based on electronic devices with chiral active layers that inform photocurrent dissymmetry (g sc ) upon illuminations of opposing CPL. Due to limited absorption dissymmetry (g abs ) in the chiral active layers, exploring the prospect of creating additional g sc in chiral electronic devices is becoming increasingly relevant. In particular, rationalizing the corresponding amplification mechanisms is still challenging. Here, we achieve accurate CPL detection through an amplified g sc from bulk heterojunction (BHJ) small-molecule organic solar cells (OSCs) with supramolecular chirality. The alternating preferential and nonpreferential CPL illuminations cause a difference in maximum absorption position across the chiral active layer, resulting in differences in exciton separation and charge recombination, transport, and collection. These differences contribute to additional difference in photocurrent output and the amplified g sc in the chiral OSCs. From the perspective of device structure, our study likely provides insights into the amplified g sc in chiral electronic devices for direct CPL detection.