With the continuous advancement of organic photovoltaic (OPV) technology, it has unlocked boundless opportunities for industrial development. In terms of OPV industrialization, the use of inverted device architecture combined with all-solution coating remains the most effective approach to simultaneously meet the dual demands of low-cost and high-throughput production. However, this approach also highlights a long-standing challenge in the OPV industry, the poor adhesion between hydrophilic hole transport layers (HTLs), such as poly(3,4-ethylenedioxythiophene) (PEDOT)-based colloids, and the hydrophobic bulk heterojunction (BHJ) layers. This adhesion issue often leads to delamination, posing reliability risks, particularly for flexible devices. To address this challenge, our study proposes a method that utilizes alignment cloth to rub the surface of the BHJ layer, thereby increasing the contact area and enhancing adhesion with the PEDOT-based colloid HTL. This technique significantly improves the adhesion between the hydrophilic HTL and hydrophobic BHJ layer, enhancing the flexibility and reliability of the devices while maintaining high efficiency. This process offers significant insights for the OPV industry and production methods, potentially serving as a revolutionary approach for future module manufacturing is believed.

Two series of electroactive poly(amide-imide)s (PAIs) were synthesized using the phosphorylation polyamidation technique, employing various imide ring-preformed dicarboxylic acids in combination with two triphenylamine (TPA)-based diamine monomers: 4,4’-diamino-4”-methoxytriphenylamine (MeO-TPA-2NH2) and N, N’-di(4-aminophenyl)-N, N’-di(4-methoxyphenyl)-1,4-phenylenediamine [(MeO)2-TPPA-2NH2]. All PAIs demonstrated excellent solubility in polar organic solvents and could be processed into strong, flexible films via solution casting. The fully aromatic PAIs exhibited high glass transition temperatures (Tg) exceeding 300 °C and did not show significant decomposition until reaching 500 °C. The incorporation of methylene units into the PAI main chain resulted in decreased Tg and thermal stability. The PAIs derived from the diamine monomer MeO-TPA-2NH2 displayed reversible redox processes, changing color from colorless to green upon oxidation. In contrast, the PAIs based on the diamine monomer (MeO)2-TPPA-2NH2 revealed two reversible redox processes, accompanied by color changes from colorless in the neutral state to green and blue in the oxidized states. Both series of PAIs exhibited remarkably high electrochemical and electrochromic switching stability.

To address the upcoming large-scale production demands of organic photodetectors (OPDs) and image sensors, there is a growing need to develop interfacial materials that balance cost-effectiveness, performance, and stability. In this work, we systematically investigated the characteristics of a solution-processed cobalt(II) acetate (Co(OAc)2) hole transport layer (HTL) in the OPDs. The work included a detailed analysis of the suitability in both conventional and inverted device architectures, the choice of the solvent system for the precursor solution, reaction conditions, and thickness optimization. We also evaluated the performance of a Co(OAc)2 HTL in a top-illuminated device architecture to assess potential applications in image sensors. The results indicated that the device composed of a Co(OAc)2 HTL exhibited lower noise current compared to the device with vacuum-based MoO3 HTLs, and the device also demonstrated excellent stability in an unencapsulated condition. Consequently, in a top-illuminated architecture composed of a short-wave infrared (SWIR) photoactive layer, the device using Co(OAc)2 as the HTL achieved a dark current density of 1.44 x 10-5 A/cm2 and a detectivity of 1.25 x 108 Jones in the SWIR region at 1260 nm, outperforming the MoO3-based device, which exhibited a dark current density of 2.47 x 10-5 A/cm2 and a detectivity of 4.73 x 107 Jones. This solution-processed HTL meets the industrial demands for performance, stability, and cost efficiency. The Co(OAc)2 HTL has the potential to become a crucial interfacial technology in OPD development, contributing to advancements in the organic image sensor industry.

The power conversion efficiency (PCE) of organic photovoltaics (OPVs) has significantly improved in recent years owing to advances in material design, highlighting the great potential of this technology. However, for industrialization, the realization of low-cost, large-area OPV modules remains a major challenge, as effective strategies to translate high-efficiency laboratory cells into scalable production are still lacking. To address this gap and emphasize the importance of module-level development, we employed a systematic interface engineering approach to optimize OPV from lab-scale cells to industrial-scale modules. Through careful selection of interlayers, along with optimized thin film thicknesses compatible with printed electrodes, we successfully demonstrated fully printed OPV modules with a PCE of 9.07% and a cell-to-module PCE loss controlled within 15%. To the best of our knowledge, this represents one of the highest efficiencies reported for large-area, fully printed OPV modules to date.

Shortwave infrared (SWIR) plays a pivotal role in shaping the next generation of optical sensing technologies, driving innovation in emerging materials and device architectures. Among the promising candidates, organic photodetectors (OPDs) have garnered considerable attention. However, their development is often hindered by the limited long-wavelength responsiveness and constrained external quantum efficiency (EQE) of organic semiconductors. In this study, an ultranarrow bandgap polymer specifically designed for efficient SWIR absorption is presented. When paired with a nonfullerene acceptor (NFA) to form a bulk-heterojunction (BHJ) blend, and integrated into a resonant microcavity device utilizing a transparent electrode with high SWIR reflectivity, the resulting OPD successfully extended its spectral response beyond 1800 nm while maintaining an exceptional EQE. As the active layer thickness (i.e., cavity length) increases, the device achieved EQEs of 12.6%, 4.2%, and 2.1% at 1620, 1750, and 1800 nm, respectively. To the best of knowledge, these represent the highest performance to date for OPD in the SWIR range beyond 1600 nm. Furthermore, the entire device can be fabricated using cost-effective, solution-processable, and scalable techniques. This breakthrough marks a significant milestone for OPD technology and opens an exciting new chapter in the advancement of organic electronic technologies is believed.

Shortwave infrared (SWIR) image sensors have unique functions in many optical applications, leading to widespread attention in developing next-generation materials and photodetector technologies. Organic photodetectors (OPDs) are highly promising due to their flexibility in molecular design and processability. However, integrating OPDs with silicon readout integrated circuits (ROICs) poses numerous challenges, often resulting in underestimated device performance and limiting technological progress. To address the requirements of integrating top-illuminated OPD with ROICs and to enhance the external quantum efficiency (EQE), optical microcavities are introduced into the OPDs. The EQE in the SWIR region can be effectively enhanced by properly adjusting the thicknesses of the photoactive layer (PAL) and interlayers. Simulations of the optical field distribution further support the active functions of the microcavity structure. The spatial variation of the microcavities allows the spectral response to shift from 1000 to 1400 nm, and the optimized device achieves an EQE of 25.8% at 1260 nm. Finally, the OPDs are integrated with a silicon-based test kit, and the results reveal comparable sensing performance, demonstrating the high potential of microcavity resonance for device integration. This design effectively improves the integration of OPDs with traditional ROICs and advances SWIR-based organic image sensor technology further toward commercialization.

Integrating organic photodetectors (OPDs) with silicon (Si)-based readout integrated circuits presents numerous challenges, particularly due to the degradation of organic semiconductors (OSCs) caused by various stresses. This issue is especially pronounced in narrow bandgap OSCs with shortwave infrared (SWIR) spectral responses, further complicating the development of organic image sensors. To address the issue, we draw inspiration from silicon- and germanium-based sensor technology, proposing a method of first fabricating bottom-illuminated SWIR OPD devices on a glass substrate and then bonding the OPD onto a Si substrate using a poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) glue to form a top-illuminated device. This architecture avoids exposing the OPDs to high temperatures and plasma bombardment during the thin-film deposition, and the glass substrate can also serve as an ideal encapsulation cover, offering a new direction for the integration of OPD-on-Si technology. Eventually, the bonded, top-illuminated device achieves a detectivity of 3.58 x 10(10) Jones at 1290 nm and -2 V bias. This advancement not only enhances the integration completeness of OPDs with Si semiconductors but also preserves the intrinsic performance of OSC materials, further bringing revolutionary changes to the organic sensing industry.

A series of fluorinated aromatic poly(ether imide)s (PEIs)(IV) containing bulky fluorene bis(ether anhydride) [(9,9-bis[4-(3,4-dicarboxyphenoxy)-phenyl]fluorene, (I)] with various fluorinated diamines (II) were prepared through polyaddition and chemical, or, thermal imidization two-stage process. The resulting PEIs have inherent viscosities of 0.50–0.58 dL/g and are readily soluble in various organic solvents. Both chemically and thermally imidized PEI films are colorless and highly transparent with cut-off wavelengths below 375 nm and yellowness index ranging from 5.4 to 13.4. They also exhibited excellent thermal stability with glass transition temperatures (Tgs) up to 297 °C and 10% weight loss temperatures (Tds) up to 583 °C in nitrogen atmosphere. Furthermore, the films have tensile strengths of 90–147 MPa and initial modulus of 2.0–2.6 GPa. Meanwhile, all the obtained fluorinated PEIs exhibited low dielectric constant of 2.69–3.19 at 1 MHz and low water uptake of 0.17–0.34%. Finally, the non-fluorinated counterparts derived from similar bis(ether anhydride) (I) with various bis(ether amine)s were prepared and compared. The results demonstrate that the fluorinated PEIs are promising candidates for high-performance films due to the bulky fluorene bis(ether anhydride) and trifluoromethyl substituted along the polymer repeat unit chain.

Balanced high transparency, thermal properties and organosolublility are urgent requirements for preparing polyimides. In this study, a series of fluorinated polyimides (Va-f) containing a multi-ether fluorinated diamine unit were designed. The corresponding PIs were synthesized through traditionally thermally polycondensation with bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]ether (II) and various commercial aromatic dinahydrides (IIIa-f). In particular, there are four rigid benzene rings and three flexible ether linkages in its fluorinated diamine structure (II), which is expected to achieve a balance in organic solubility and thermal properties. Va-f had inherent viscosity ranging from 0.88 to 1.24 dL/g. In addition, these fluorinated PIs exhibited high organo-solubility in common organic solvents and mechanical properties of tensile strengths of 92–116 MPa, tensile moduli of 2.0–42.3 GPa, elongations at break of 10–36

Incorporation of a non-fullerene acceptor (NFA) into an organic bulk-heterojunction currently has realized the extendable spectral response and high photocurrent generation in organic photodiodes. However, to allow these organic materials to be industrially commercialized, the thermal stability which enables the materials to survive under the process integration and operation needs to be considered. Generally, NFA small molecules showed high crystallinity, which aggregated through heating and led to the poor thermal stability. To tackle the thermal stability issue of highly efficient NFAs, two IDIC-based NFA dimers─IDIC-T Dimer and IDIC-TT Dimer─were designed, synthesized, and characterized; the thermal stability of the BHJ layer incorporating these dimer molecules was evaluated and compared with that of the BHJ layer using the monomer, IDIC-4Cl, as acceptors. Eventually, a power conversion efficiency of 9.44% was achieved for organic photovoltaic devices based on the NFA dimer. The dimers also showed remarkable thermal stability than the IDIC-4Cl monomer, which provided a promising direction for the polymer/small-molecule system in organic photodiodes for industrial practicability.

The synthesis and characterization of pendant methyl fluorinated polyimides (5a-f) derived from fluorinated diamine monomer, 2 '-methyl-1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (2) and several aromatic dianhydrides (3a-f) is described. The synthesis of new fluorinated diamine (2) and the precursor fluorinated dinitro compound (1) are also discussed. The presence of trifluoromethyl group in the backbone of the fluorinated polyimide exhibited better optical transparency, organic solubility, dielectric constant, moisture adsorption and maintained mechanical and thermal properties than trifluoromethyl-free analogs (5 ' a-f). The highly fluorinated polyimides 5f via chemical imidization exhibited the best organic solubility, highest optical properties (b* cutoff wavelength = 367 nm). In addition, the highly fluorinated polyimide via thermal imidization also displayed relative lower dielectric constants (3.06 at 1 MHz) and moisture adsorption (0.16%) than most fluorinated polyimides. The t-butyl and phenyl substituted fluorinate diamine analogs and their fluorinated polyimides were also compared and discussed on thermal and mechanical properties.

A series of fluorinated poly (ether imide)s (PEIs) were prepared from asymmetry, bulky featured of 1,2-bis(3,4-dicarboxyphenoxy)-4-tert-butylbenzene dianhydride and various trifluoromethyl-based bis(ether amine)s via conventional thermal (H) or chemical (C) imidization. All fluorinated PEIs exhibited flexible, good mechanical properties and excellent solubility in a variety of organic solvents. In addition, the chemical imidization based PEI thin films showed cut-off wavelengths of UV-vis absorptions below 380 nm with very low yellowness index (b* < 5.5). They also exhibited high thermal stability with the 10 % weight loss temperature from 486 to 550 °C of in nitrogen or air atmosphere. Compared with the corresponding PEIs based on non-fluorinated bis(ether amine)s, fluorinated PEIs not only showed higher optical transparency, lower dielectric constants and water absorptions but also maintained thermal and mechanical properties.

A series of new fluorinated aromatic poly(ether imide)s (PEIs) were prepared from highly contorted 2,2′-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride and various trifluoromethyl-containing bis(ether amine)s via chemical or thermal imidization. All the PEIs showed good solubility in a variety of organic solvents and could afford flexible, colorless, and transparent thin films via solution-casting. They showed cut-off wavelengths of Uv-vis absorptions below 380 nm and very low yellowness index (b* < 7.0). They also showed high thermal stability with the 10% weight loss temperature from 503 to 585 °C of in nitrogen or air atmosphere. The glass transition temperatures (T gs) are recorded in the range of 194–254 °C by DSC. For a comparative study, another series of non-fluorinated PEIs derived from the same biphenyl-2,2′-diol bis(ether anhydride) with various bis(ether amine)s without the trifluoromethyl substituents were also synthesized and characterized.

Indium phosphide (InP) quantum dots (QDs) with luminescence tunable over the entire visible spectrum were prepared by the conventional hot injection method. InP QDs are considered alternatives to Cadmium containing QDs for application in light-emitting devices because of showing similar optical properties to those containing toxic heavy metals. The multishell coating was shown to improve the photoluminescence quantum yield (QY) of InP QDs more strongly than the conventional ZnS shell coating. QY values were more than 60% along with FWHM of 41-73 nm can be routinely achieved, making the optical performance of InP/ZnS/ZnS or InP/ZnS/SiO 2 QDs comparable to that of InP/ZnS QDs. These QDs and the polymer dissolved in the appropriate solvent and deposited by casting to give homogeneous films and showed a good level of dispersion of the QDs within the polymer.

An anti-reflection thin film with a mesoporous structure is demonstrated to improve the light-collection and photocurrent-generation abilities of organic photovoltaic cells. The mesoporous film was prepared by sol–gel-derived silica with an excimer ultraviolet-radiation removable self-assembling triblock copolymer as the nanostructured template. The method for fabricating this film was much easier than conventional processes used to prepare anti-reflection materials as they involve vacuum or high-temperature conditions. By using this mesoporous film as an anti-reflection coating on the glass side of an indium tin oxide-coated glass substrate, an enhancement of about 6% in the photocurrent generation could be achieved in a device with a poly(3-hexylthiophene):(6,6)-phenyl-C61-butyric acid methyl ester bulk-heterojunction layer. A glass substrate with a coating of the mesoporous anti-reflection film showed an obvious improvement in transmittance for wavelengths extending from the visible-light region to the near-infrared region. The result also indicates that the prepared anti-reflection material is not only compatible with the photoactive materials with wide band gaps but works very well with semiconductors with small band gaps as well, e.g. thieno(3,4-b)-thiophene/benzodithiophene copolymer (PTB7). In this work, ~3.6% photocurrent enhancement can also be obtained in PTB7-based solar cells, indicating the wide compatibility of thus-prepared mesoporous film.

A series of novel fluorinated polynaphthalimides (PNIs) (2a–g) were synthesized from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) and trifluoromethyl (CF3)-substituted aromatic bis(ether amine)s (1a–g) by high-temperature solution polycondensation in m-cresol using isoquinoline as catalyst. Almost all the PNIs were readily soluble in polar solvents such as N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc) and could be solution-cast to transparent and tough films with high tensile strengths. The PNIs exhibited high thermal stability, with glass-transition temperatures of 262–383°C, 10% weight loss temperatures above 528°C in nitrogen or air, and char yields at 800°C in nitrogen higher than 50%. In comparison with analogous PNIs without the –CF3 substituents, these fluorinated PNIs revealed an enhanced solubility and better film-forming capability.

AbstractA series of novel fluorinated poly(ether imide)s (PEIs) IVa-h were synthesized from 4,4’-(2,5-tolylenedioxy)diphthalic anhydride (I) and various trifluoromethyl-substituted aromatic bis(ether amine)s (IIa-h) via a conventional two-step method with thermal or chemical imidization of the precursor poly(amic acid)s. These PEIs were readily soluble in a variety of organic solvents; they were soluble with a concentration higher than 10% in amide-type polar solvents, ether type solvents, and chlorinated hydrocarbons. The solution-cast films showed a high optical transparency and low color intensity, with an ultraviolet-visible absorption edge of 371- 377 nm and low b* values (a yellowness index) of 4.9-7.5. These films were strong and tough with tensile strength of 90-103 MPa. They exhibited glass-transition temperatures (Tg) in the range of 207-293oC, with 10% weight loss temperature in excess of 500oC in air or nitrogen atmosphere. They also showed low-dielectric constants (2.95-3.37 at 1 MHz) and low moisture absorption (0.20- 0.67 wt %).

A series of polyimide precursors, poly(amic acid)s, containing propyltrimethoxysliane at two chain ends were prepared from 4,4 '-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (1) with six commercially available dianhydrides, followed by end-capping with 3-ammopropyltrimethoxysilane (APrTMOS). A new class of fluorine-containing polyimide /silica composite films (III) with chemical bonds between the fluorinated polyimide backbone and the silica network has been synthesized from the APrTMOS-terminated precursors with tetramethoxysilane via the sol-gel process and thermal cyclodehydration. The resultant hybrid films were light-colored, flexible, and tough. They had high levels of thermal stability associated with high glass-transition temperatures (> 251 degrees C), 10% weight-loss temperatures in excess of 527 degrees C, and char yields at 800 degrees C in nitrogen higher than 60%. For a comparative study, the analogous nonfluorinated polyimide/silica hybrid films (III '), based on 4,4 '-bis (4-aminophenoxy)biphenyl (I ') and the neat fluorinated polyimide films (IV), based on diamine I, were also synthesized and characterized. The hybrid films of the fluorinated series III showed a higher transparency and less color intensity when compared with the nonfluorinated III ' analogs. They also revealed a lower refraction index and birefringence than pure polyimides (IV). (C) 2007 Wiley Periodicals, Inc.

A novel bis(ether amine) monomer, 5,5′-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]-4,7-methanohexahydroindan (2), was synthesized through the nucleophilic aromatic substitution reaction of 5,5′-bis-(4-hydroxyphenyl)-4,7-methanohexahydroindan with 2-chloro-5-nitrobenzotrifluoride to yield the intermediate dinitro compound, followed by catalytic reduction with hydrazine and Pd/C. A series of polyimides were synthesized from 2 and various aromatic dianhydrides using a standard two-stage process with chemical or thermal imidization of poly(amic acid). All of these polymer films were soluble in amide-type solvents above 10% w/v, had tensile strengths of 97–117 MPa, and the 10% weight loss temperature was above 464 °C with their residues exceeding 46% at 800 °C in nitrogen. Compared with the non-fluorinated polyimides, the fluorinated series were observed to have lower dielectric constants (2.92–3.28 at 1 MHz) and lower moisture absorptions (0.15–0.43 wt%) as well as lower color intensity and better solubility. Copyright © 2006 Society of Chemical Industry