Impact of Aryl End Group Engineering of Donor Polymers on the Morphology and Efficiency of Halogen-Free Solvent-Processed Nonfullerene Organic Solar Cells

End group engineering on the side chain of π-conjugated donor polymers is explored as an effective way to develop efficient photovoltaic devices. In this work, we designed and synthesized three new π-conjugated polymers (PBDT-BZ-1, PBDT-S-BZ, and PBDT-BZ-F) with terminal aryl end groups on the side chain of chlorine-substituted benzo­[1,2-b:4,5b′]­dithiophene (BDT). End group modifications showed notable changes in energy levels, dipole moments, exciton lifetimes, energy losses, and charge transport properties. Remarkably, the three new polymers paired with IT-4F (halogen-free solvent processed/toluene:DPE) displayed high power conversion efficiencies (PCEs) compared to a polymer (PBDT-Al-5) without a terminal end group (PCE of 7.32%). Interestingly, PBDT-S-BZ:IT-4F (PCE of 13.73%) showed a higher PCE than the benchmark PM7:IT-4F. The improved performance of PBDT-S-BZ well correlates with its improved charge mobility, well-interdigitated surface morphology, and high miscibility with a low Flory–Huggins interaction parameter (1.253). Thus, we successfully established a correlation between the end group engineering and bulk properties of the new polymers for realizing the high performance of halogen-free nonfullerene organic solar cells

Olfactory receptor expression levels in olfactory marker protein-positive non-olfactory tissues using RT-qPCR analyses.

<p>*Values are mean fM of mRNA ± SEM. Quantitative real-time RT-PCR was used to analyze the levels of mRNA of 11 olfactory receptors (ORs) in mouse tissues. Olfactory bulb was used as a positive control for OR expression.</p><p>*OR mRNA was quantified in reference to the <i>p</i>CI-rho-olfr544 plasmid standard and normalized to eEF-2 RNA, n = 3 independent mice.</p><p>Olfactory receptor expression levels in olfactory marker protein-positive non-olfactory tissues using RT-qPCR analyses.</p

Identification of OMP (+) cells in non-olfactory tissues such as bladder and thyroid.

<p>Olfactory marker protein (OMP) expression (red in b and f) is superimposed with each marker using double-labeling immunohistochemical techniques. A representative image is shown for each antibody combination. The left panels show each marker protein with Dylight 488-conjugated anti-rabbit IgG green fluorescence (a, e), the middle panels show OMP with Cy3-conjugated anti-goat IgG red fluorescence (b, f), and the right panels are the merged images of the two individual images in the corresponding rows (c, g). C-kit (green in a), a marker for the bladder (BL in <b>A</b>), stains interstitial cells of Cajal (ICC). Calcitonin (green in e) is a marker for parafollicular cells (also known as C cells) of the thyroid (TR in <b>B</b>). OMP is expressed in each cell type of mouse tissue as evidenced by colocalization with c-kit (yellow in c) and calcitonin (yellow in g). C-kit/OMP (d) and calcitonin/OMP (h) colocalization was supported by quantitative analysis. ***, <i>P</i> < 0.0001 using an unpaired <i>t</i>-test; ##, <i>P</i> = 0.0004, and ###, <i>P</i> = 0.0001 using a Mann—Whitney <i>U</i> test OMP + c-kit, or calcitonin versus marker or OMP alone. Results are the means ± SEM of three or four independent areas (n = 3–5 mice). Scale bar: 10 μm.</p

Protein expression profiles of OMP in various mouse tissues.

<p>Double immunoassay for olfactory marker protein (OMP). <b>(A)</b> In all tissues except for kidney (KD), the results of double immunoassays demonstrate the presence of OMP. Total mouse tissue extract (100 μg for olfactory epithelium [OE] and 20 mg for KD, skeletal muscle [SM], and thymus [TM]) was immunoprecipitated (IP) with goat anti-OMP antibodies and immunoblotted with rabbit anti-OMP antibody (double immunoassay). The apparent molecular mass of OMP (arrow) is 19 kDa in OE, SM, and TM [OMP (-)], and this band is completely blocked by preincubating the OMP antibody with purified recombinant OMP [OMP (+)]. <b>(B)</b> Mouse tissue survey for OMP expression. Total tissue extract (100 μg for OE as a positive control, 3 mg for thyroid (TR), and 20 mg for all other tissues) was used for IP. * indicates immunoglobulin. LV, liver; BL, bladder; PC, pancreas; ST, stomach; DD, duodenum; TT, testis; SP, spleen; HT, heart; LG, lung.</p

Immunohistochemical detection of OMP in mouse non-olfactory tissues.

<p><b>(A)</b> Olfactory marker protein (OMP) staining in olfactory epithelium (OE) was used as a positive control. In the thyroid (TR), OMP (+) cells are observed between follicles (FL) and are similar to a parafollicular cell-like population. OMP (+) cells of the bladder (BL) are assumed to be in the submucosal layer. In the testis (TT), OMP signals are displayed in Leydig cell-like populations belonging to interstitial tissue (IT), and in the thymus (TM), OMP is detected in the medullary area. The asterisks indicate OMP (+) cells. <b>(B)</b> Each tissue represents samples stained in the absence of primary antibody. MU, mucosa; SML, submucosal layer; ML, muscle layer; ST, seminiferous tubule. Scale bar: 10 μm.</p

Finely Tuned Molecular Packing Realized by a New Rhodanine-Based Acceptor Enabling Excellent Additive-Free Small- and Large-Area Organic Photovoltaic Devices Approaching 19 and 12.20% Efficiencies

A new nonfullerene acceptor (NFA), BTA-ERh, was synthesized and integrated into a PM6:Y7:PC71BM ternary system to regulate the blend film morphology for enhanced device performance. Due to BTA-ERh’s good miscibility with host active blend films, an optimized film morphology was obtained with appropriate phase separation and fine-tuning of film crystallinity, which ultimately resulted in efficient exciton dissociation, charge transport, lower recombination loss, and decreased trap-state density. The resulting additive-free quaternary devices achieved a remarkable efficiency of 18.90%, with a high voltage, fill factor, and current density of 0.87 V, 76.32%, and 28.60 mA cm–2, respectively. By adding less of a new small molecule with high crystallinity, the favorable nanomorphology shape of blend films containing NFAs might be adjusted. Consequently, this strategy can enhance photovoltaic device performance for cutting-edge NFA-based organic solar cells (OSCs). In contrast, the additive-free OSCs exhibited good operational stability. More importantly, large-area modules with the quaternary device showed a remarkable efficiency of 12.20%, with an area as high as 55 cm2 (substrate size, 100 cm2) in an air atmosphere via D-bar coating. These results highlight the enormous research potential for a multicomponent strategy for future additive-free OSC applications

Co-expression of OMP with either ACIII or G_olf in non-olfactory tissues using immunohistochemical analysis.

<p>The distribution of each olfactory signaling-associated molecule, namely, olfactory marker protein (OMP), adenylate cyclase III (ACIII), and olfactory G-protein (G_olf), in non-olfactory tissues shows different expression patterns. In bladder (BL) and thymus (TM), OMP (+) cells are co-expressed with ACIII and G_olf. OMP signals expressed in the thyroid (TR) are colocalized with ACIII, but not with G_olf. In the heart (HT) and testis (TT), OMP signals are displayed alone, which is not coincident with G_olf or ACIII.</p

Validation of commercial antibodies against the olfactory receptor (OR).

<p>A heterologous OR expression system and the endogenous OR expression in olfactory epithelium (OE) was used to validate commercially available OR antibodies against specific ORs. HEK 293 cells were transiently transfected with cDNAs coding for several associated proteins (G_olf, Ric8b, and RTP1S) and ORs (olfr544, olfr1386, olfr558, olfr1496, or OR51E1 [a human olfr558 ortholog]), and immunolabeled using antibodies against both the N-terminal epitope-Rho tag (A, E, I, M, and P) and each OR-specific antibody (B, F, J, N, and Q). The olfr1386 (B) and olfr544 (F) antibody detect Lucy-Flag-Rho-olfr1386- and Rho-olfr544-constructs in the transfected cells, respectively. These results are confirmed using the anti-Rho antibody (A and E; C and G for overlay). As a positive control, both antibodies recognize unique olfactory receptor neuron (ORN) (D and H) in OE. OR51E1 and anti-Rho antibody detect Rho-OR51E1 (J and I) and Rho-olfr558 (N and M) constructs in the transfected cells and ORN (L), which is expected since they share 94% amino acid identity as orthologs. The olfr1496 is detected by anti-Rho antibody (P), but not by commercial olfr1496 antibody (Q; R for overlay), which nonspecifically recognizes all ORN (S) in OE. Scale bar = 10 μm.</p

Identification of OMP (+) cells in thymus.

<p>Olfactory marker protein (OMP) expression was superimposed on each marker using double-labeling immunohistochemical assays. A representative image is shown for each antibody combination. The left panels show each marker protein (CD8 for T cells; CD45R for B cells; Iba-1 for macrophages; and keratin 14 [K14] for medullary epithelial cells). The middle panels show OMP, and the right panels are the merged images of the two individual images in the corresponding rows. OMP is co-labeled the subpopulation of K14-positive cells, but not other cell types, indicating that OMP is within thymic medullary epithelial cells (mTEC).</p