Organic solar cells (OSCs) based on the PM6:Y6 donor-acceptor system have achieved remarkable efficiency. However, further performance enhancement remains constrained by partial exciton utilization, nonradiative recombination losses, and energetic disorder in the active layer. Here, we introduce a noncondensed acceptor, NFA6, as a third component into the PM6:Y6 host binary blend to regulate exciton dynamics and recombination pathways. Spectroscopic investigations including steady-state, time-resolved photoluminescence, and transient absorption under selective excitation reveal pronounced exciton quenching and accelerated charge generation in ternary blends. A significant spectral overlap between emission of NFA6 and absorption of Y6 indicates an efficient energy transfer process, which enhances exciton harvesting and contributes to an increased short-circuit current density (JSC). Incorporation of 20% (w/w) NFA6 optimizes the nanoscale morphology, promoting efficient charge dissociation and transportation while suppressing bimolecular and trap-assisted recombination. Energetic disorder evaluation further reveals reduced nonradiative losses in the ternary system compared with the binary counterpart. Consequently, the optimized inverted PM6:Y6:NFA6 ternary device achieves a power conversion efficiency of 16.72%, significantly exceeding 14.11% efficiency in the binary PM6:Y6 device fabricated fully under open-air conditions. This enhancement is due to increased JSC, fill factor, reduced voltage loss, improved charge carrier mobility, and prolonged carrier lifetime, confirming more efficient exciton dissociation and suppressed recombination in the ternary system. These findings reveal that the noncondensed acceptor functions primarily as an excitonic sensitizer rather than a direct charge-separating component. This work provides new insights into exciton management strategies for minimizing voltage losses and advancing high-performance ternary OSCs.

Semitransparent organic solar cells (ST-OSCs) with functional characteristics demonstrate potential application in agricultural greenhouses, building-integrated photovoltaics, and smart windows. Herein, we report a flexible optical engineering strategy to tailor the transmission spectra of ST-OSCs via rational design of nanophotonic structures (NPSs). By regulating the internal optical field distribution, the NPSs enable application-oriented optimization of device performance without modifying the active layer. A solid additive, 2-bromo-6-methoxynaphthalene, is used to optimize the active-layer morphology and enhance charge transport, providing a robust device foundation for NPS modulation. The champion device employing NPS-1 and anti-reflection coating (ARC) achieves a power conversion efficiency (PCE) of 13.26%, an average visible transmittance (AVT) of 43.8%, and a record light utilization efficiency (LUE) of 5.80%. By tuning the structure of NPS, the transmittance spectra can be adapted for different scenarios: The ARC&NPS-2 configuration yields a high color rendering index of 90.6 with a LUE of 5.00% for building-integrated photovoltaics, while the ARC&NPS-3 configuration delivers a plant growth factor of 36.2% with a LUE of 5.25% for application in agricultural greenhouses. All NPS-integrated ST-OSCs maintain infrared rejection above 88%. These results establish NPSs as a versatile platform for realizing ST-OSCs with tailored functional properties.

The alkyl side chains in the core in the A-D-A nonfused ring nonfullerene acceptors significantly influence the photocurrent generation and overall power conversion efficiency (PCE) in the organic solar cells (OSCs). Here in, we have designed two A-D-pi-D-A unfused NFAs featuring the identical central pi-ethynylene linker and BTA terminal acceptor (A) unit but utilizing dithiophenepyrrole (DTP) with different side chains, i.e., octyldodecyl (OD) (NFA-8) and 2-hexyldecyl (HD) (NFA-9). The investigations were focused on their optical and electrochemical properties. When paired with PBDB-T as the donor, the OSCs utilizing PBDB-T:NFA-8 and PBDB-T:NFA-9 attained PCE of about 9.95 and 13.90%, respectively. The improved PCE for NFA-9-based OSCs is primarily attributed to the increased short circuit current and fill factor (FF). The higher short circuit current and FF in the NFA-9-based OSCs could be attributed to the prolonged exciton lifetime for NFA-9, effective separation of exciton into free charge carriers, and their successive collection in the NFA-9-based OSCs. Due to the absorption spectra of these bulk heterojunction active layers being restricted to 810 nm, these NFAs can have a potential for indoor OSCs and guest acceptors for ternary and front subcells for tandem OSCs.

In this study, we report the synthesis of two A1-D-A2-D-type conjugated polymers P139 and P141 with distinct optical bandgaps, prepared via direct arylation polycondensation. Both polymers incorporate a common wide-bandgap acceptor unit (A1) based on a carbazole-fused dithienoquinoxaline structure and a thiophene donor (D) unit. The key difference lies in their second acceptor unit (A2). P139 contains a diketopyrrolopyrrole-based moiety, while P141 features a difluorobenzotriazole-based fragment. Optical and electrochemical characterizations reveal that P139 exhibits a narrow bandgap of 1.34 eV with HOMO and LUMO energy levels at -5.25 eV and -3.68 eV, respectively. In contrast, P141 shows a wider bandgap of 2.00 eV, with HOMO and LUMO levels at -5.46 eV and -3.47 eV. Binary and ternary organic solar cells (OSCs) were fabricated using these polymers as donor materials in combination with a medium-bandgap non-fullerene acceptor (NFA-5). The optimized ternary device, based on a P139:P141:NFA-5 blend, delivered a power conversion efficiency (PCE) of 16.42%, significantly outperforming the binary devices, which achieved 12.12% (P139:NFA5) and 9.48% (P141:NFA5). The enhanced performance of the ternary OSC is attributed to broadened and complementary absorption, efficient energy transfer from P141 to P139, improved exciton dissociation due to an increased donor-acceptor interfacial area, balanced charge transport, reduced recombination losses, and improved charge extraction.

Semitransparent organic solar cells(ST-OSCs)are promising for building-integrated photovoltaics,offer-ing power generation,transparency and heat insulation.High performance ST-OSCs need sophisticated optical management to balance the competing demands of power conversion efficiency(PCE)and aver-age visible transmittance(AVT)for various applications.Here,a type of aperiodic band-pass filter(ABPF)made from LiF and ZnS are developed to selectively alter visible light transmission and near-infrared(NIR)reflection.This ABPF allows the active layers of ST-OSCs to re-harvest unabsorbed NIR photons,compensating for the loss of photocurrent caused by the high AVT of ST-OSCs.By carefully adjusting the thicknesses of individual layers within ABPFs,we can modulate their photonic bandgaps,enabling ST-OSCs to achieve multifunctional performance.ST-OSCs combined with the ABPF-1 demonstrate a remarkable light utilization efficiency(LUE)of 5.40％,a PCE of 14.21％and an AVT of 38.0％,which repre-sent some of the highest values reported for ST-OSCs.Moreover,the ST-OSCs are equipped with excellent color neutrality and heat insulation functions.The ST-OSCs employing ABPF-2 exhibit a LUE of 4.78％,a color rendering index of 87.5 and an infrared rejection rate of 91.6％.This work offers an effective method for employing ABPFs in the creation of high-performance multifunctional ST-OSCs.

Phenothiazine-based molecules are often used as electron donors in organic solar cells (OSCs). Herein, for the first time, we present the design and synthesis of a coumarin-phenothiazine dyad (AM-3) as a wide-band-gap fullerene-free acceptor (FFA) for OSCs. Most importantly, the molecule was synthesized in a simple and cost-effective two-step condensation reaction. Air-processed binary OSCs, containing AM-3 as an acceptor and PTB7-Th as the donor, yield a power conversion efficiency (PCE) of 12.46% and an open-circuit voltage (VOC) of 0.99 V. Further, an improved PCE of 14.96% is achieved by introducing AM-3 as a third component in the PTB7-Th:NFA-5 blend, marking an enhancement of 40% over its PTB7-Th:NFA-5 binary counterpart (10.66%). Considering the synthetic simplicity and low cost, the obtained PCEs for AM-3 are comparable to those of several high-performance acceptors. We further evaluate the synthetic complexity (SC) and figure of merit (FoM) of AM-3 and compare them with commonly used fused- and nonfused-ring electron acceptors to evaluate its prospects for future applications.

Four new donor-acceptor conjugated polymers based on the acceptor block 8,10-bis(2-octyldodecyl)-8H-dithieno[3 ',2 ':5,6;2 '',3 '':7,8]naphtho[2,3-d]imidazole-9(10H)-one and various donor moieties were synthesized. Binary and ternary composites comprising new polymers, PC71BM fullerene and non-fullerene acceptors based on indacenodithiophene, were developed. The mobility of electrons and holes in thin films of the ternary composites is balanced in contrast to that in binary composite films. This is explained by less aggregation in the ternary composite films and good matching of the frontier orbital energy levels of the composite components.

Here in, we have designed two new unfused non-fullerene small molecules using asymmetric benzo[1,2-b:3.4-b', 6,5-b"]trithiophene (BTT) as the central donor core and different terminal units i. e., 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (NFA-4) and 1,3-diethyl-2-thioxodi hydropyrimidine-4,6 (1H,5H)-dione (NFA-5) and examined their optical and electrochemical properties. Using a wide band-gap copolymer D18, organic solar cells (OSCs) based on bulk heterojunction of D18:NFA-4 and D18:NFA-5 showed overall power conversion efficiency (PCE) of about 17.07 % and 11.27 %, respectively. The increased PCE for the NFA-4-based OSC, compared to NFA-5 counterpart, is due higher value of short circuit current (JSC), open circuit voltage (VOC), and fill factor (FF). Following the addition of small amount of NFA-5 to the binary bulk heterojunction D18:NFA-4, the ternary organic solar cells attained a PCE of 18.05 %, surpassing that of the binary counterparts due to the higher values of which is higher than that for the binary counterparts and attributed to the increased values of JSC, FF, and VOC. The higher value of JSC is linked to the efficient use to excitons transferred from NFA-5 to NFA-4 with a greated dipole moment than NFA-5 and subsequently dissociated into a free charge carrier efficiently.

We observed and studied the phenomenon of the redox front propagation in different polyaniline (PAni) deposited samples interfaced with liquid or solid polymeric electrolyte. The front of electrochemical conversion, in which the insulator and the conductor parts of PAni are interfaced, is studied observing the temporal evolution of the conductivity of PAni samples. The propagation of redox front was studied in electrochemically obtained thick (2 µm) and in thin (50 nm) poly-aniline films, obtained using Langmuir-Blodgett (LB) method. In the configuration that we tested, the speed of the red-ox front propagation for the thin LB films was found to be 200 micron/sec opening the way for the manufacturing large neural networks, realized using PAni based memristive devices, in which the memristance can be quickly changed in the programmable manner. The prototypes of the spiking neuron connections were manufactured on the basis of lithographically developed gold contacts, bridged by electrochemically grown polyaniline and placed under polymer electrolyte layer with only one counter electrode (gate) for the whole manifold of pseudo-two-terminal memristor bridges. The spike propagation was studied in such gold-polyaniline systems. The research opens the possibility of miniature spike or rate-based neural network circuits manufacture, based on metal pads and polyaniline.

Two donor–acceptor (D–A) backbone copolymers with different fused ring acceptors, i.e., dithieno [2,3‐e:3′,2′‐g]isoindole‐7,9(8 H)‐dione (DTID) and dithieno[3′,2′:5,6;2″,3″:7,8]naphtho[2,3‐d]imidazol‐9(10 H)‐one (DTNID) and same benzo[1,2‐b:4,5‐b′]dithiophene with alkylated aromatic side as side chains (BDTT) donor, denoted as P133 and P135 are synthesized and used as donor along with narrow bandgap nonfullerene Y6 acceptor for the preparation of polymer solar cells (PSCs). The dielectric constant of P135 :Y6 is higher than that of P133 :Y6 due to the strong electron deficient ability of DTNID compared to DTID, which fostered exciton dissociation and charge transport, constrained charge recombination, and ultimately boosted the power conversion efficiency of P135 :Y6 to 15.11%, which is higher than P133 :Y6 (10.24%). Therefore, these investigations confirm the pronounced potential of fused ring DTNID as an acceptor unit for emerging D–A copolymers for PSCs with high efficiency.

The power conversion efficiency of the ternary PSCs (16.32%) is higher than that for binary counterparts, i.e., 13.16% and 12.62% for P(DTB-BDD):DBTBT-IC and P(DTB-BDD):Y6, respectively.

A [3 + 2] cycloaddition reaction using dialkyne and diazide comonomers, both bearing explosophoric groups, to synthesize energetic polymers containing furazan and 1,2,3-triazole ring as well as nitramine group in the polymer chain have been described. The developed solvent- and catalyst-free approach is methodologically simple and effective, the comonomers used are easily available, and the resulting polymer does not need any purification. All this makes it a promising tool for the synthesis of energetic polymers. The protocol was utilized to generate multigram quantities of the target polymer, which has been comprehensively investigated. The resulting polymer was fully characterized by spectral and physico-chemical methods. Compatibility with energetic plasticizers, thermochemical characteristics, and combustion features indicate the prospects of this polymer as a binder base for energetic materials. The polymer of this study surpasses the benchmark energetic polymer, nitrocellulose (NC), in a number of properties.

We have designed a new medium bandgap non-fullerene small-molecule acceptor consisting of an IDT donor core flanked with 2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]-thiophene-4-ylidene) malononitrile (TC) acceptor terminal groups (IDT-TC) and compared its optical and electrochemical properties with the IDT-IC acceptor. IDT-TC showed an absorption profile from 300 to 760 nm, and it has an optical bandgap of 1.65 eV and HOMO and LUMO energy levels of -5.55 and -3.83 eV, respectively. In contrast to IDT-IC, IDT-TC has an upshifted LUMO energy level, which is advantageous for achieving high open-circuit voltage. Moreover, IDT-TC showed higher crystallinity and high electron mobility than IDT-IC. Using a wide bandgap D-A copolymer P as the donor, we compared the photovoltaic performance of IDT-TC, IDT-IC, and IDT-IC-Cl nonfullerene acceptors (NFAs). Polymer solar cells (PSCs) using P: IDT-TC, P: IDT-IC, and P:IDT-IC-Cl active layers achieved a power conversion efficiency (PCE) of 14.26, 11.56, and 13.34%, respectively. As the absorption profiles of IDT-IC-Cl and IDT-TC are complementary to each other, we have incorporated IDT-TC as the guest acceptor in the P: IDT-IC-Cl active layer to fabricate the ternary (P:IDT-TC: IDT-IC-Cl) PSC, demonstrating a PCE of 16.44%, which is significantly higher than that of the binary BHJ devices. The improvement in PCE for ternary PSCs is attributed to the efficient exploitation of excitons via energy transfer from IDT-TC to IDT-IC-Cl, suitable nanoscale phase separation, compact stacking distance, and more evenly distributed charge transport.

A new acceptor unit anthra[1,2-b: 4,3-b': 6,7-c'']trithiophene-8,12-dione (А3Т) (A2) is synthesized and used to design D-A1 -D-A2 medium bandgap donor copolymers with same thiophene (D) and A2 units but different A1, i.e., fluorinated benzothiadiazole (F-BTz) and benzothiadiazole (BTz) denoted as P130 and P131, respectively. Their detailed optical and electrochemical properties are examined. The copolymers show good solubility in common organic solvents, broad absorption in the visible spectral region from 300 to 700 nm, and deeper HOMO levels of -5.45 and -5.34 eV for P130 and P131, respectively. Finally, an optimized polymer solar cell (PSC) based on P131 as the donor and narrow bandgap non-fullerene small molecule acceptor Y6 demonstrated a power conversion efficiency (PCE) of >11.13%. To further improve the efficiency of the non-fullerene PSC, the P130 is optimized by introducing a fluorine atom into the BTz unit, F-BTz acceptor unit, and PCE PSC based on P130: Y6 active layer increased to >15.28%, which is higher than that for the non-fluorinated analog P131:Y6. The increase in the PCE for former PSC is attributed to the more crystalline nature and compact π-π stacking distance, leading to more balanced charge transport and reduced charge recombination. These remarkable results demonstrate that A3T-based copolymer P130 with F-BTz as the second acceptor is a promising donor material for high-performance PSCs.

We have achieved a power conversion efficiency of 16.44% for the ternary polymer solar cell using a wide bandgap copolymer and two non-fullerene acceptors.

A simple synthesis of highly planar extended π ‐electron molecules is of particular interest for the development of efficient nonfullerene acceptors in organic solar cells with high light absorption and high mobility. Herein, two small‐molecule acceptors ( MPU7 and MPU8 ) with a diketopyrrolopyrrole core connected to CPTCN end‐capping groups (A 2 ) via thienylethynylselenophene ( MPU7 ) or thienylethynylthiophene ( MPU8 ) linkers are conceived and synthesized. Planarity of the conjugated skeleton is achieved in both molecules, thanks to the existence of four (Se⋯O or S⋯O) noncovalent, through‐space intramolecular interactions. Both nonfullerene small‐molecule acceptors show broad absorption in the visible and near‐infrared region (up to 930 nm). As a result, the binary solar cells constructed together with a polymer donor (P) display power conversion efficiencies as high as 14.12%. Devices built with MPU7 (containing the selenophene) show better film morphology, electron mobility, and higher efficiency than those containing thiophene ( MPU8 ).

Two D-A copolymers consisting of fused ring pyrrolo-dithieno-quinoxaline acceptors are synthesized with different donor units, i.e., benzodithiophene (BDT) with alkylthienyl (P134) and 2-ethylhexyloxy (P117) side chains. These copolymers are used as donors and a narrow bandgap acceptor Y6 to fabricate bulk heterojunction polymer solar cell devices. Owing to the strong electron-deficient fused ring pyrrolo-bithieno-quinoxaline and weak alkyl thienyl side chains in BDT, the polymer solar cells (PSCs) based on P134:Y6 attain the power conversion efficiency (PCE) of 15.42%, which is higher than the P117:Y6 counterpart (12.14%). The superior value of PCE for P134:Y6 can be associated with more well-adjusted charge transport, weak charge recombination, proficient exciton generation, and dissociation into free charge carriers and their subsequent charge collection owing to the dense π-π stacking distance and more considerable crystal coherence length for the P134:Y6 thin films. This investigation confirms the great potential of a strong acceptor-weak donor tactic for developing efficient D-A copolymers consists of quinoxaline acceptor for PSCs.

We have designed and synthesized two wide bandgap new donor-acceptor (D-A) copolymers consisting of the same alkylthiazole-substituted benzo[1,2-b;4,5-b ']dithiophene (BDTTz) donor unit and but different acceptor units, i.e., thiazolo[5,4-d]thiazole (TTZ) (P122) and 1,3,-4 thiadiazole (TDz) (P123) and investigated their optical and electrochemical properties. We have employed these copolymers as donor and fullerene (PC71BM) and narrow bandgap non-fullerene (Y6) as acceptor, to fabricate binary and ternary bulk heterojunction polymer solar cells (PSCs). The overall power conversion efficiency (PCE) of optimized binary bulk heterojunction PSCs based on P122:Y6 and P123:Y6 is 12.60% and 13.16%, respectively. The higher PCE for PSCs based on P123 than P122 counterparts may be associated with the broader absorption profile of the P123 and more charge carrier mobilities than that for the P122 active layer. With the incorporation of small amount of PC71BM into either P122:Y6 or P123:Y6 binary blend, the corresponding ternary PSCs showed an overall PCE of 14.89% and 15.52%, respectively, which is higher than the binary counterparts using either Y6 or PC71BM as acceptor. Incorporating the PC71BM in the binary host blend increases the absorption in the 300-500 nm wavelength region, generating more excitons in the active ternary layer and helping to dissociate the excitons into free charge carriers more effectively. The more appropriate nanoscale phase separation in the active ternary layer than the binary counterpart may be one of the reasons for higher PCE.

Three new donor-acceptor conjugated polymers incorporating same dithieno [2,3-e;3 ' 2 '-g]isoindole-7,9 (8H) (DTID) as medium acceptor and different donors, i.e., dithienosilole (DTS) PDTID-DTS (P1), dithieno-benzene (DTB) PDTID-DTB (P2) and dibenzothiophene (BDT) PDTID-BDT (P3) as a donor have been synthesized and explored for non-fullerene based BHJ polymer solar cells (PSCs). These copolymers had optical band gaps of 1.83-2.07 eV and HOMO energy levels of -5.37 to -5.67 eV. The P2 consists of a DTB donor unit that results in a deeper HOMO level of -5.67 eV, which may be due to the weak electron-donating nature of DTB. Pairing with the narrow bandgap non-fullerene acceptor BThIND-Cl, the P1, P2, and P3-based PSCs showed overall power conversion efficiency of 14.76 %, 7.22 % and 13.13 %, respectively. The PSCs based on P2 and P1 showed the highest and lowest values of open-circuit voltage, respectively, consistent with their HOMO energy levels. The lowest value of PCE for P2 may be associated with the negative HOMO offset between the P2 and BThIND-Cl, which hamper the hole transfer from the HOMO of BThIND-Cl to P2, resulting in a low value of short circuit current and fill factor. The higher value of PCE of 14.76 % for P1 may be related to the broader absorption profile of the active layer and balanced charge transport, more appropriate nanoscale phase separation, and compact 7C-7C stacking distance, leading to the high value of short circuit current and fill factor.

An electron acceptor in a bulk heterojunction (BHJ) is one of the significant factors for the performance of organic solar cells (OSCs). Acceptors are required to possess an appropriate energy level to be well fitted with donors and a complementary absorption profile in the near-infrared (NIR) region of solar spectra. Herein, two novel star-shaped electron acceptors TBT-1 and TBT-2 denoted as 3a and 3b, respectively, based on a planar truxene core conjugated with three 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) units were designed. Both 3a and 3b show strong absorption in both visible and NIR regions in solution and in films. Due to the strong electron-donating capability of the dimethylamino group and a good pi-conjugative effect, 3a displays a slightly higher highest occupied molecular orbital (HOMO) level (-5.40 eV) and a deeper lowest unoccupied molecular orbital (LUMO) level (-3.96 eV) compared to 3b (HOMO = -5.52 eV and LUMO = -3.94 eV), resulting in red-shifted absorption, showing a narrower optical band gap of 1.44 eV than that of 3b (1.58 eV). When blended with a donor polymer P, the OSCs based on P:3a and P:3b exhibit a superior short-circuit current density (J(sc)), high electron mobility, and open-circuit voltage (V-oc). OSCs based on optimized P:3a and P:3b exhibit the best power conversion efficiency (PCE) values of 13.41 and 11.75%, respectively. To the best of our knowledge, this is among the best values for OSCs with a non-fullerene small-molecule acceptor (NFSMA) based on BODIPY derivatives. These outcomes suggest that integrating extended conjugation into a star-shaped building block encourages designing high-performance NFSMAs for application in OSCs.