New Synthetic Approaches to N-Aryl and π-Expanded Diketopyrrolopyrroles as New Building Blocks for Organic Optoelectronic Materials.

Diketopyrrolopyrrole (DPP) as a building block has been intensively investigated for organic semiconductors and light emitting materials. The synthesis of N-aryl DPPs remains challenging. Herein, we firstly report a new easily handled synthetic method toward N-aryl DPPs through H-DPP with diaryliodonium salt in the presence of CuI, which shows broad reaction scope. Sixteen N-aryl DPPs, including phenyl, furan and thiophene as flanking aromatic groups, were synthesized with yields up to 78 %. These N-aryl DPPs are fluorescent in both solutions and solid states, with quantum yields up to 96 % and 40 %, respectively. Moreover, we show that the reaction between H-DPP and diaryliodonium salt can lead to π-expanded DPPs by using Pd(OAc)2 as catalyst. Nine π-expanded DPPs were obtained in 27-61 % yields. These π-expanded DPPs exhibit good semiconducting properties with hole mobility of 0.71 cm2 V-1 s-1 , demonstrating that they are useful building blocks for high performance organic semiconductors.

Anti-stigmatizing: a collaborative autoethnography on recovery from depression.

Introduction: Despite extensive research on clinical treatments for depression, there remains a significant gap in understanding of the lived experiences and recovery journeys of those with depression. This study sought to explore the recovery process through an "anti-stigmatizing" lens, emphasizing the cultural-psychological mechanisms at play and the importance of personal narratives in shaping the recovery trajectory. Methods: Using a collaborative autoethnographic approach, this report focuses on the first author's journey of depression recovery. This research methodology allows for an in-depth exploration of subjective experiences, with a specific emphasis on the interaction between societal stigma, personal identity, and mental-health challenges. Results: It is found that the depression-recovery experience can be divided into four stages from an anti-stigma perspective: (1) encountering the public stigma of emotions; (2) internalizing the stigma to a self-stigma; (3) "decriminalizing" the expected stigma of a "depressed" identity through diagnosis; and (4) being able to cope with and understanding the public stigma relating to depression when facing it again. Key factors that were found to contribute to recovery were self-awareness, community empowerment, and recognition and acceptance by close friends and family. Discussion: We propose a reconceptualization of depression that incorporates a societal perspective on internalized stigma. Recovery from depression is not merely a medical process; it also pertains to how the patient frees themselves from public stigma. The results strongly indicate the need for a paradigm shift toward a more inclusive and empathetic approach to mental-health care, and we emphasize the importance of personal narratives in depression recovery.

Biomimetic nanocluster photoreceptors for adaptative circular polarization vision.

Nanoclusters with atomically precise structures and discrete energy levels are considered as nanoscale semiconductors for artificial intelligence. However, nanocluster electronic engineering and optoelectronic behavior have remained obscure and unexplored. Hence, we create nanocluster photoreceptors inspired by mantis shrimp visual systems to satisfy the needs of compact but multi-task vision hardware and explore the photo-induced electronic transport. Wafer-scale arrayed photoreceptors are constructed by a nanocluster-conjugated molecule heterostructure. Nanoclusters perform as an in-sensor charge reservoir to tune the conductance levels of artificial photoreceptors by a light valve mechanism. A ligand-assisted charge transfer process takes place at nanocluster interface and it features an integration of spectral-dependent visual adaptation and circular polarization recognition. This approach is further employed for developing concisely structured, multi-task, and compact artificial visual systems and provides valuable guidelines for nanocluster neuromorphic devices.

Organic donor-acceptor heterojunctions for high performance circularly polarized light detection.

Development of highly efficient and stable lateral organic circularly polarized light photodetector is a fundamental prerequisite for realization of circularly polarized light integrated applications. However, chiral semiconductors with helical structure are usually found with intrinsically low field-effect mobilities, which becomes a bottleneck for high-performance and multi-wavelength circularly polarized light detection. To address this problem, here we demonstrate a novel strategy to fabricate multi-wavelength circularly polarized light photodetector based on the donor-acceptor heterojunction, where efficient exciton separation enables chiral acceptor layer to provide differentiated concentration of holes to the channel of organic field-effect transistors. Benefitting from the low defect density at the semiconductor/dielectric interface, the photodetectors exhibit excellent stability, enabling current roll-off of about 3-4% over 500 cycles. The photocurrent dissymmetry value and responsivity for circularly polarized light photodetector in air are 0.24 and 0.28 A W-1, respectively. We further demonstrate circularly polarized light communication based on a real-time circularly polarized light detector by decoding the light signal. As the proof-of-concept, the results hold the promise of large-scale circularly polarized light integrated photonic applications.

Chlorinated Spiroconjugated Fused Extended Aromatics for Multifunctional Organic Electronics.

The synthesis of a new molecule, SFIC-Cl, is reported, which features enhanced π-electron delocalization by spiroconjugation and narrowed bandgap by chlorination. SFIC-Cl is integrated into a single-crystal transistor (OFET) and organic light-emitting diode (OLED). The material demonstrates remarkable transport abilities across various solution-processed OFETs and retains efficient radiance in a near-infrared OLED emitting light at 700 nm. Furthermore, the intermolecular multi-dimensional connection of SFIC-Cl enables the fabrication of a single-component large-area (2 × 2 cm2 ) near-infrared OLED by spin-coating. The SFIC-Cl-acceptor-based solar cell shows excellent power conversion efficiency of 10.16% resulting from the broadened and strong absorption and well-matched energy levels. The study demonstrates that chlorinated spiroconjugated fused systems offer a novel direction toward the development of high-performance organic semiconductor materials for hybrid organic electronic devices.

New fused conjugated molecules with fused thiophene and pyran units for organic electronic materials.

Rigid and planar conjugated molecules have substantial significance due to their potential applications in organic electronics. Herein we report two highly fused ladder type conjugated molecules, TTCTTC and TTTCTTTC, with up to 10 fused rings in which the fused-thiophene rings are fused to the chromeno[6,5,4-def]chromene unit. Both molecules show high HOMO levels and accordingly they can be oxidized into their radical cations with absorptions extending to 1300 nm in the presence of trifluoroacetic acid. Thin films of TTCTTC and TTTCTTTC exhibit p-type semiconductor properties with hole mobilities up to 0.39 cm2 V-1 s-1. Moreover, TTCTTC shows a high fluorescence quantum yield of up to 16.5% in the solid state.

Efficient Nonfullerene Organic Solar Cells with Small Driving Forces for Both Hole and Electron Transfer.

State-of-the-art organic solar cells (OSCs) typically suffer from large voltage loss (Vloss ) compared to their inorganic and perovskite counterparts. There are some successful attempts to reduce the Vloss by decreasing the energy offsets between the donor and acceptor materials, and the OSC community has demonstrated efficient systems with either small highest occupied molecular orbital (HOMO) offset or negligible lowest unoccupied molecular orbital (LUMO) offset between donors and acceptors. However, efficient OSCs based on a donor/acceptor system with both small HOMO and LUMO offsets have not been demonstrated simultaneously. In this work, an efficient nonfullerene OSC is reported based on a donor polymer named PffBT2T-TT and a small-molecular acceptor (O-IDTBR), which have identical bandgaps and close energy levels. The Fourier-transform photocurrent spectroscopy external quantum efficiency (FTPS-EQE) spectrum of the blend overlaps with those of neat PffBT2T-TT and O-IDTBR, indicating the small driving forces for both hole and electron transfer. Meanwhile, the OSCs exhibit a high electroluminescence quantum efficiency (EQEEL ) of ≈1 × 10-4 , which leads to a significantly minimized nonradiative Vloss of 0.24 V. Despite the small driving forces and a low Vloss , a maximum EQE of 67% and a high power conversion efficiency of 10.4% can still be achieved.