All-polymer phototransistors with bulk heterojunction sensing layers of thiophene-based electron-donating and thienopyrroledione-based electron-accepting polymers

All-polymer phototransistors consisting of bulk heterojunction (BHJ) nanolayers of electron-donating (p-type) and electron-accepting (n-type) polymers are attractive candidates for applications such as light-sensing and light-switching devices. Here, we report efficient green-light-sensing all-polymer phototransistors based on BHJ layers of poly(3-hexylthiophene) (P3HT) and poly[(4,8-bis(2-ethylhexyloxy)-benzo[1,2-b:4,5-b]-dithiophene)-2,6-diyl-alt-(N-2-ethylhexylthieno[3,4-c]pyrrole-4,6-dione)-2,6-diyl]] (PBDTTPD) polymers. To understand the phototransistor characteristics, all devices were exposed to a green monochromatic light (555 nm) with different incident power intensities. The results showed that the P3HT:PBDTTPD (80:20) layer are more advantageous than the pristine P3HT layers in terms of efficient charge separation and transport. The responsivity value of devices with the P3HT:PBDTTPD (80:20) layers reached 33.3 A/W, which is 25 and 28 times higher than those obtained with pristine the pristine P3HT or P3HT:PBDTTPD (60:40) layers. The enhanced device performance of the P3HT:PBDTTPD (80:20) phototransistors is attributable to an efficient charge separation, prevalent edge-on chain orientation, and relatively smoother surface morphology, which might facilitate improved charge transport in the lateral direction.     

Effects of solution-processed polymer interlayers on hole injection and device performance of polymer light-emitting diodes

We present studies of current density and photometric efficiency using three well known, commercially available polyphenylenevinylene and polyfluorene based light-emitting polymers (LEPs) with different interlayers. The thin, spin-coated interlayers of poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine) (TFB) and poly[9,9-dioctyl-fluorene-co-(bis-N,N′-(3-carboxyphenyl)-bis-N,N′-phenylbenzidine)] (BFA) are placed between the poly(3,4-ethylenedioxythiophene)/polystyrenesulphonic acid (PEDOT:PSS) anode and the LEP. It is found that despite having very similar HOMO levels (±0.1 eV) to the LEPs, the interlayers alter both the hole injection efficiency and the photometric efficiency of PLED devices. The increase or decrease of these depends on the particular interlayer-LEP combination involved, but there is a strong, general correlation between poorer hole injection resulting in a higher photometric efficiency. We attribute the variation in hole injection to the altered morphology and contact area at the anode interfaces, with the possible involvement of mobility-dependant space-charge effects or charge trapping. The dominant process in improving the photometric efficiency must be better electron-hole current balance, and/or the shift of the recombination zone to a more favourable position with less exciton quenching. The interlayers do not act as electron blocking layers, but hole injection enhancement by electron injection does seem to occur. These results show that interlayers can both increase and decrease device performance, depending on the interlayer-LEP combination involved.     

Stable and efficient blue fluorescent organic light-emitting diode by blade coating with or without electron-transport layer

Multi-layer small-molecule blue fluorescent organic light-emitting diode (OLED) is fabricated by blade coating. The emission layer is based on a mixed host of 1-(7-(9,9′-bianthracen-10-yl)-9,9-dioctyl-9H-fluoren-2-yl)pyrene (PT-404) and electron-transport material 2,7-Bis(diphenylphosphoryl)-9,9′ -spirobifluorene (SPPO13), and the blue guest emitter is 4-4′-(1E,1′E)-2,2′-(naphthalene-2,6-diyl)bis(ethane-2,1-diyl)bis(N,N-bis(4-hexyl- Phenyl) aniline) (Blue D). A hole-transport layer of Poly-(9, 9-dioctylfluorenyl-2, 7-diyl)-co-(4, 4-(N-(4-sec-butylphenyl)) diphenylamine) (TFB) is added on top of PEDOT: PSS anode. The electrons are blocked away from TFB by a layer of pure host emission layer of PT-404 between TFB and the mixed –host emission layer. For the device with the electron transport layer of Tris(8-hydroxyquinolinato)aluminum (Alq₃) blade-coated over the emission layer the efficiency and lifetime at initial brightness of 500 cd m⁻² are 7.5 cd A⁻¹ and 150 h for Alq₃/CsF/Al cathode. When the Alq₃/CsF/Al is replaced by simply CsF/Al over the mixed-host emission layer the efficiency and lifetime are 6.4 cd A⁻¹ and 300 h (2 times longer than that of the Alq₃/CsF/Al cathode). The lifetime depends on the electron-hole balance tuned by the mixed-host blending ratio as well as the electron injection from the cathode. This work shows good stability is possible for all-solution-processed blue OLED.     

Solvent-dependent morphology of thermally converted copper phthalocyanine for solution-processed small molecule organic photovoltaic devices

We fabricated copper phthalocyanine (CuPc)-based organic photovoltaic (OPV) devices via a solution process. CuPc was obtained through thermal conversion of its precursor CuPc(OMe)₂, which has excellent solubility in various organic solvents, on a substrate. Solvent-dependent performance of the resulting devices was observed, which could be explained by considering film morphology. Using a 1:2 (wt/wt) mixture of chlorobenzene and chloroform produced a p–n type OPV device with a power conversion efficiency of 1.35% under 1 sun simulated AM1.5G solar illumination.     

Electronic structure and carrier transport at laminated polymer homojunctions

Soft contact lamination, whereby films prepared separately from solution are brought into contact to form a single device, was used here to form homojunctions comprising two identical layers of poly(3-hexylthiophene) (P3HT) or two layers of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′-3}-thiadiazole)] (F8BT). Using ultraviolet photoemission spectroscopy (UPS), Kelvin Probe Force Microscopy (KPFM), and current–voltage (I–V) measurements, the electronic structure of, and carrier transport across, these homojunctions were investigated. UPS and KPFM show that lamination does not introduce any significant offset in the molecular levels across the interface. The I–V characteristics confirm this result by showing that transport across the film is largely unaffected by the presence of the laminated interface. This important result means that lamination could become a versatile tool for constructing multi-layer polymer devices.     

Efficient ternary organic solar cells based on immiscible blends

Organic photovoltaic cells based on ternary blends of materials with complementary properties represent an approach to improve the photon-absorption and/or charge transport within the devices. However, the more complex nature of the ternary system, i.e. in diversity of materials' properties and morphological features, complicates the understanding of the processes behind such optimizations. Here, organic photovoltaic cells with wider absorption spectrum composed of two electron-donor polymers, F8T2, poly(9,9-dioctylfluorene-alt-bithiophene), and PTB7, poly([4,8-bis[(2′-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2′-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]), mixed with [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) are investigated. We demonstrate an improvement of 25% in power conversion efficiency in comparison with the most efficient binary blend control devices. The active layers of these ternary cells exhibit gross phase separation, as determined by Atomic Force Microscopy (AFM) and Synchrotron-based Scanning Transmission X-ray Microscopy (STXM).     

Influences of charge of conjugated polymer electrolytes cathode interlayer for bulk-heterojunction polymer solar cells

Two fluorene-based conjugated polymer electrolyte (CPE) poly[(9,9-bis(6′-(N,N,N-trimethylammonium)hexyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFNBr) and poly[9,9-bis(4′-sulfonatobutyl)fluorene-alt-2,7-(9,9-dioctylfluorene)] sodium salt (PFSO₃Na), bearing amine groups and anionic sulfonate groups on side chains respectively, are synthesized and applied as cathode interlayer in polymer solar cells. Both of the hydrophilic CPEs can well modify the interfacial properties and allow ohomic contact between the activelayer and cathode. The opposite charges exert great influence on the effective work function of cathode and interfacial interaction through the orientation of the interfacial dipole at the active layer/metal electrode interface, subsequently influence the resulting device performance. Compared with the cationic PFNBr, PFSO₃Na with anionic sulfonate groups can dramatically reduce the work function of Al by accumulation of the polar groups at the PFSO₃Na/Al interface to induce more favorable the interfacial dipole. The better energy alignment for electron extraction and transportation at active layer/Al interface is confirmed by a significant enhancement of V_OC. The better wettability and morphology of PFSO₃Na on the active layer and the more effective motion of sodium counterion further modify the barrier to facilitate electron extraction and transportation. Moreover, 14% and 22% performance enhancement can also be achieved respectively, when PFNBr and PFSO₃Na are used as interlayers for low bandgap poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT)-based solar cells.     

Charge injection and transport studies of poly(2,7-carbazole) copolymer PCDTBT and their relationship to solar cell performance

The charge injection and transport properties of a high performance semiconducting polymer for organic photovoltaic (OPV) applications, poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT), are investigated by time-of-flight (TOF) and dark-injection space-charge-limited current (DI-SCLC) techniques. OPV cells employing PCDTBT are known to possess power conversion efficiency (PCE) exceeding 6% [1], [2]. While TOF probes only the hole mobilities of a thick film, DI-SCLC is shown to be useful down to a sample thickness of ～200 nm, which is comparable to thicknesses used in OPV cells. We show that for pristine PCDTBT, the hole mobilities for both thick used in TOF and thin films for DI-SCLC are essentially the same, and they are in the range of 0.4–3.0 × 10^?4 cm²/Vs at room temperature. Both poly(3,4-ethylene dioxythioplene) doped with poly(strenesulfonate) (PEDOT:PSS) and molybdenum (VI) oxide (MoO₃) form quasi-Ohmic contacts to PCDTBT with better hole injection from MoO₃. Furthermore, the Gaussian Disorder Model (GDM) was employed to analyze the hopping transport of PCDTBT thin films. We show that PCDTBT possesses a relatively large energetic disorder (σ) of ～129 meV, which is significantly higher than the σ of poly(3-hexylthiophene) (P3HT) processed under similar conditions. The correlation between σ and OPV device performance is addressed.     

Polymer Solar Cells Exceeding 10% Efficiency Enabled via a Facile Star‐Shaped Molecular Cathode Interlayer with Variable Counterions

A series of star‐shaped small molecular cathode interlayer materials are synthesized for PTB7:PC₇₁BM based polymer solar cells (PSCs), comprising neutral amino groups, quaternary ammonium ions, amino N‐oxides, and sulfobetaine ions as pendant polar functionalities, respectively. For the first time, the effect of these different pendant functional groups with or without mobile counterions on the cells' photovoltaic properties is investigated in detail. A large improvement in device performance is observed by inserting these cathode interfacial layers (CILs) between the PTB7:PC₇₁BM active layer and the Al electrode. The CILs could effectively lower the work function of the Al cathode, increase the built‐in potential, and decrease the series resistance of the related PSCs. poly(9,9‐dioctylfluorene‐co‐N‐[4‐(3‐methyl‐propyl)]‐diphenylamine) with pendant quaternary ammonium ions shows the best cathode modification ability, giving rise to the highest power conversion efficiency of 10.1%, even better than that of the typical poly[(9,9‐bis(3′‐(N,N‐dimethylamino)propyl)‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctylfluorene)] based device. The design strategy and structure–property relationships concluded in this work will be helpful to develop more efficient cathode interface materials for high‐performance PSCs in the future.     

Optimization of carrier transport layer: A simple but effective approach toward achieving high efficiency all-solution processed InP quantum dot light emitting diodes

High performance quantum dot light emitting diodes (QD-LED) are being considered as a next-generation technology for energy efficient solid-state lighting and displays. In recent years, cadmium (Cd)-based QLEDs have made great progress in performance, which is close to commercial applications. However, the performance of environmentally friendly Cd-free QD-LED still needs to be improved. In this letter, using InP/ZnS quantum dots (QDs), an environmentally friendly red QDs material, as the light emitting layer, low-cost all-solution processed red InP/ZnS QD-LED are fabricated. The optimized device with a hybrid multilayered structure employing an organic double hole transport layer (HTL) with doping small molecules (TFB/PVK:TAPC) and an inorganic ZnMgO nanoparticles (NPs) electron transport layer (ETL), here TFB, PVK and TAPC represent poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4’-(N-(p-butylphenyl))-diphenylamine)], poly (9-vinlycarbazole) and 1,1-bis [4-[N,N′-di (p-tolyl)amino]phenyl]-cyclohexane, respectively. The best device exhibits a peak current efficiency (CE) of 7.58 cd A⁻¹, which is 2.4 times higher than the control device using PVK (HTL) and ZnO (ETL). At the same time, turn-on voltage dropped from 2.8 V (control devices) to 2.4 V. These superb QD-LED performances originate not only from the improved hole injection by the introduction of a double hole layer and the reduced the quenching of excitons by using ZnMgO NPs ETL but also from increasing the hole mobility with doping of small molecule materials in PVK to balance the carrier transportation. This work provides a simple and feasible idea with optimization the carrier transport for realizing high-efficiency QD-LED devices.     

Fully solution-processed and multilayer blue organic light-emitting diodes based on efficient small molecule emissive layer and intergrated interlayer optimization

Efficient and fully solution-processed blue organic light-emitting diodes (OLEDs) based on fluorescent small-molecule and methanol/water soluble conjugated polymer as electron-injection material are reported. The emitting layer is 3,6-bis(9,9,9′,9′-tetrakis (6-(9H-carbazol-9-yl)hexyl)-9H,9′H-[2,2′-bifluoren]-7-yl)dib-nzo[b, d]thiophene 5, 5-dioxide (OCSoC) with a blue-fluorescent small-molecule, and a methanol/water soluble polymer poly[(9,9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyl-fluorene)] (PFN) acted as electron-injection layer (EIL). All the organic layers are spin-coated from solution. The multilayer device structure with emitting layer/electron-injection layer is achieved by solution-processed method without the dissolution problem between layers. The performances of the devices show that the maximum luminous efficiency of the multilayer device is increased about 43%, compared to the single-layer device. PFN acting as the EIL material plays a key role in the improvement of the device performance when used in solution-processed small-molecule OLEDs.     

Elucidating the role of current injection on the influence of open-circuit voltage in small-molecule organic photovoltaic devices: From the aspects of charge transfer and electroluminescent spectrum

We demonstrate that the open-circuit voltage (V_OC) of organic photovoltaic (OPV) devices composed of rubrene and C₆₀ can be considerably different when the anode and active layer are changed. Two types of anodes and active layers were compared. In plasma-treated indium-tin-oxide (ITO) OPV devices, the parameter V_OC exhibits an improvement from 0.68 V to 0.76 V when the device structure is varied from a bilayer to a mixed structure. However, in the OPV devices that use ITO/MoO₃ as the anode, a similar V_OC is observed regardless of the device structure. A series of temperature-dependent measurements are conducted to investigate these results. The calculation of barrier height at the rubrene/C₆₀ (or rubrene:C₆₀) interface yields the prediction of V_OC, suggesting that an excess energetic loss occurs in the mixed structures. The electroluminescent (EL) spectra of these devices show that the mixed structure can completely quench the EL of rubrene single layer. A broad band of the charge transfer (CT) emission is observed clearly. A temperature-dependent measurement for the extracting injection barrier is conducted and shows that the mixed structure is favorable for the hole current injection. The CT properties are obtained using the external quantum efficiency and EL spectra of the OPV devices. We find that the nonradiative recombination loss is highly correlated with the injected current; the lower the injection barrier induced the less the nonradiative recombination loss. Therefore, the parameter V_OC can be improved when the injected current is increased.     

Correlating Emissive Non‐Geminate Charge Recombination with Photocurrent Generation Efficiency in Polymer/Perylene Diimide Organic Photovoltaic Blend Films

Evidence for a correlation between the dynamics of emissive non‐geminate charge recombination within organic photovoltaic (OPV) blend films and the photocurrent generation efficiency of the corresponding blend‐based solar cells is presented. Two model OPV systems that consist of binary blends of electron acceptor N′‐bis(1‐ethylpropyl)‐3,4,9,10‐perylene tetracarboxy diimide (PDI) with either poly(9,9‐dioctylfluorene‐co‐benzothiadiazole) (F8BT) or poly(9,9‐dioctylindenofluorene‐co‐benzothiadiazole) (PIF8BT) as electron donor are studied. For the F8BT:PDI and PIF8BT:PDI devices photocurrent generation efficiency is shown to be related to the PDI crystallinity. In contrast to the F8BT:PDI system, thermal annealing of the PIF8BT:PDI layer at 90 °C has a positive impact on the photocurrent generation efficiency and yields a corresponding increase in PL quenching. The devices of both blends have a strongly reduced photocurrent on higher temperature annealing at 120 °C. Delayed luminescence spectroscopy suggests that the improved efficiency of photocurrent generation for the 90 °C annealed PIF8BT:PDI layer is a result of optimized transport of the photogenerated charge‐carriers as well as of enhanced PL quenching due to the maintenance of optimized polymer/PDI interfaces. The studies propose that charge transport in the blend films can be indirectly monitored from the recombination dynamics of free carriers that cause the delayed luminescence. For the F8BT:PDI and PIF8BT:PDI blend films these dynamics are best described by a power‐law decay function and are found to be temperature dependent.     

Novel cationic water-soluble polyfluorene derivatives with ion-transporting side groups for efficient electron injection in PLEDs

Synthesis of cationic water-soluble polyfluorene derivatives with various side groups, which are used as electron injecting layers in polymer light emitting diodes, is described. Neutral polyfluorene derivatives containing bromo-alkyl terminal groups were synthesized by a palladium catalyzed Suzuki coupling reaction. The bromo-alkyl terminal groups in the neutral polyfluorenes were quaternized by treatment with a trimethyl amine solution. When a high work-function metal such as Ag is used as a cathode in a light emitting diode with an ITO/PEDOT:PSS/MEH-PPV/water-soluble polyfluorene/Ag configuration, effects of these water-soluble polyfluorenes on the device performance were investigated. In the case of poly[(9,9-bis((6′-(N,N,N-trimethylammonium) hexyl)-2,7-fluorene))-alt-(9,9-bis(2-(2-methoxyethoxy)ethyl)-fluorene)] Dibromide (WPF-oxy-F) containing ethylene oxide groups as the electron injecting layer, the electroluminescence efficiency of light emitting devices was significantly enhanced by about two orders of magnitude compared to that of a device without an electron injecting layer because migration of bromide ions via the ethylene oxide side groups led to large space charge. As a result, the injection barrier could be reduced between the emitting layer and Ag cathode resulting high electroluminescence efficiency.     

Efficient organic photovoltaics using solution-processed,annealing-free TiO2 nanocrystalline particles as an interface modification layer

A solution-processed, annealing-free TiO₂ nanocrystalline particles (TiO₂ NPs) as an interface modification layer was inserted in organic photovoltaics (OPVs), in which the widely used polymer poly (3-hexyl thiophene) (P3HT), a low band gap alkoxylphenyl substituted [1,2-b:4,5-b′] dithiophene-based polymer (PBDTPO-DTBO), and a soluble small molecule benzodithiophene derivative (TIBDT) were used as the donor material, respectively. The annealing-free TiO₂ NPs could be easily spin-coated upon the surface of organic active layers, and showed comparable properties to thermal-annealed ones. The power conversion efficiencies (PCEs) of OPV devices could be enhanced dramatically with inserting an annealing-free TiO₂ NPs layer. The PCEs of OPV devices based on P3HT:PC₆₁BM, PBDTPO-DTBO:PC₇₁BM and TIBDT:PC₆₁BM bulk heterojunctions were improved by 28%, 15% and 27%, respectively, with an annealing-free TiO₂ NPs layer, in which the highest PCE of 5.76% was achieved in PBDTPO-DTBO:PC₇₁BM OPVs. The solution-processed, annealing-free TiO₂ NPs thin films show great potential applications in the fabrication of large-area OPVs by printing or coating techniques on flexible polymer substrates. In particularly, it would promote to fabricate solution-processed, annealing-free OPV devices with suitable hole transport layer and organic/polymer active materials.     

Small molecule tandem organic photovoltaic cells incorporating an α-NPD optical spacer layer

We report an improvement in power conversion efficiency in a small molecule tandem organic photovoltaic (OPV) device by the optimisation of current balancing of the sub-cells using an optical spacer layer. A co-deposited layer of N,N’-bis(1-naphthyl)-N,N′-diphenyl-1,1’-biphenyl-4,4’-diamine (α-NPD) and molybdenum oxide was used as the optical spacer layer and provided a highly transparent and conductive layer. Optical simulations showed the addition of the optical spacer in a boron subphthalocyanine (SubPc)/C₆₀ based tandem OPV device increased the SubPc absorption in the front sub-cell and resulted in current balancing through the device. Fabricated tandem OPV devices showed similar trends, with the power conversion efficiency increasing from 2.3% to 4.2% with the addition of an optimised optical spacer thickness. External quantum efficiency and total absorption efficiency measurements back up the optical model data which attribute the increased performance to improved SubPc absorption in the front sub-cell, balancing the photocurrents of the two sub-cells.     

Comparison of dimethyl sulfoxide treated highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) electrodes for use in indium tin oxide-free organic electronic photovoltaic devices

Indium tin oxide (ITO)-free organic photovoltaic (OPV) devices were fabricated using highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the transparent conductive electrode (TCE). The intrinsic conductivity of the PEDOT:PSS films was improved by two different dimethyl sulfoxide (DMSO) treatments – (i) DMSO was added directly to the PEDOT:PSS solution (PEDOT:PSS_ADD) and (ii) a pre-formed PEDOT:PSS film was immersed in DMSO (PEDOT:PSS_IMM). X-ray photoelectron spectroscopy (XPS) and conductive atomic force microscopy (CAFM) studies showed a large amount of PSS was removed from the PEDOT:PSS_IMM electrode surface. OPV devices based on a poly(3-hexylthiophene):[6,6]-phenyl-C₆₁-butyric acid methyl ester (P3HT:PCBM) bulk hetrojunction showed that the PEDOT:PSS_IMM electrode out-performed the PEDOT:PSS_ADD electrode, primarily due to an increase in short circuit current density from 6.62 mA cm⁻² to 7.15 mA cm⁻². The results highlight the importance of optimising the treatment of PEDOT:PSS electrodes and demonstrate their potential as an alternative TCE for rapid processing and low-cost OPV and other organic electronic devices.     

Influence of aluminium electrode preparation on PCE values of polymeric solar cells based on P3HT and PCBM

The main goal of the paper was investigation of influence of aluminum electrode preparation via thermal evaporation (TE) and the magnetron sputtering (MS) on power conversion efficiency (PCE) of polymeric solar cells. The photovoltaic properties of such three kinds devices based on poly(3-hexylthiophene-2,5-diyl) (P3HT) as ITO/P3HT/Al, ITO/P3HT:PCBM (1:1, w/w)/Al and ITO/PEDOT:PSS/P3HT:PCBM (1:1, w/w)/Al were investigated. For the constructed devices impedance spectroscopy were analyzed. For devices lack of PEDOT:PSS layer or lack of PCBM, photovoltaic parameters were very low and similar to the parameters obtained for device with Al electrode prepared by magnetron sputtering. The devices comprising PEDOT:PSS with P3HT:PCBM showed the best photovoltaic parameters such as a V_OC of 0.60 V, J_SC of 4.61 mA/cm², FF of 0.21, and PCE of 5.7 × 10^?1%.     

Highly efficient near-infrared thermally activated delayed fluorescence material based on a spirobifluorene decorated donor

The development of red/near-infrared (NIR) thermally activated delayed fluorescence (TADF) emitters are relatively lagging due to the spin statistics and energy gap law. Herein, we designed and synthesized a new NIR TADF emitter, 3-(4-(9,9′-spirobi[fluorene]-3-yl(phenyl)amino)phenyl)acenaphtho[1,2-b]pyrazine-8,9-dicarboni-trile (SDPA-APDC), by incorporating a spiro-type electron-donating moiety N,N-diphenyl-9,9′-spirobi[fluorene]-2-amine (SDPA) to an electron-withdrawing unit acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile (APDC). The photophysical, electrochemical and thermal properties of SDPA-APDC have been systematically explored. Consequently, the emitter was found high photoluminescence quantum yield (PLQY), narrow bandgap, small singlet-triplet energy gap (ΔE_ST) and excellent thermal stability. Furthermore, SDPA-APDC was developed for electroluminescence devices. The doped devices of SDPA-APDC achieved a red emission peak at 696 nm with a maximum external quantum efficiency (EQE) of 10.75%. And the non-doped device exhibited a NIR emission peak at 782 nm with a maximum EQE of 2.55%